Package 'reservr'

Title: Fit Distributions and Neural Networks to Censored and Truncated Data
Description: Define distribution families and fit them to interval-censored and interval-truncated data, where the truncation bounds may depend on the individual observation. The defined distributions feature density, probability, sampling and fitting methods as well as efficient implementations of the log-density log f(x) and log-probability log P(x0 <= X <= x1) for use in 'TensorFlow' neural networks via the 'tensorflow' package. Allows training parametric neural networks on interval-censored and interval-truncated data with flexible parameterization. Applications include Claims Development in Non-Life Insurance, e.g. modelling reporting delay distributions from incomplete data, see Bücher, Rosenstock (2022) <doi:10.1007/s13385-022-00314-4>.
Authors: Alexander Rosenstock [aut, cre, cph]
Maintainer: Alexander Rosenstock <[email protected]>
License: GPL
Version: 0.0.3.9000
Built: 2024-11-22 05:10:19 UTC
Source: https://github.com/ashesitr/reservr

Help Index

Convert TensorFlow tensors to distribution parameters recursively

Description

Convert TensorFlow tensors to distribution parameters recursively

Usage

as_params(x)

Arguments

x

possibly nested list structure of tensorflow.tensors

Value

A nested list of vectors suitable as distribution parameters

Examples

if (interactive()) {
  tf_params <- list(
    probs = k_matrix(t(c(0.5, 0.3, 0.2))),
    shapes = k_matrix(t(c(1L, 2L, 3L)), dtype = "int32"),
    scale = keras3::as_tensor(1.0, keras3::config_floatx())
  )
  params <- as_params(tf_params)
  dist <- dist_erlangmix(vector("list", 3L))
  dist$sample(10L, with_params = params)
}

Transition functions for blended distributions

Description

Transition functions for blended distributions

Usage

blended_transition(x, u, eps, .gradient = FALSE, .extend_na = FALSE)

blended_transition_inv(x, u, eps, .component)

Arguments

x

Points to evaluate at
u

Sorted vector of blending thresholds, or rowwise sorted matrix of blending thresholds
eps

Corresponding vector or matrix of blending bandwidths. Must be positive and the same dimensions as u, or scalar. No rowwise blending regions (u - eps, u + eps) may overlap.
.gradient

Also evaluate the gradient with respect to x?
.extend_na

Extend out-of range transitions by the last in-range value (i.e. the corresponding u) or by NA?
.component

Component index (up to length(u) + 1) to invert.

Value

blended_transition returns a matrix with length(x) rows and length(u) + 1 columns containing the transformed values for each of the blending components. If .gradient is TRUE, an attribute "gradient" is attached with the same dimensions, containing the derivative of the respective transition component with respect to x.

blended_transition_inv returns a vector with length(x) values containing the inverse of the transformed values for the .componentth blending component.

Examples

library(ggplot2)
xx <- seq(from = 0, to = 20, length.out = 101)
blend_mat <- blended_transition(xx, u = 10, eps = 3, .gradient = TRUE)
ggplot(
  data.frame(
    x = rep(xx, 2L),
    fun = rep(c("p", "q"), each = length(xx)),
    y = as.numeric(blend_mat),
    relevant = c(xx <= 13, xx >= 7)
  ),
  aes(x = x, y = y, color = fun, linetype = relevant)
) %+%
  geom_line() %+%
  theme_bw() %+%
  theme(
    legend.position = "bottom", legend.box = "horizontal"
  ) %+%
  guides(color = guide_legend(direction = "horizontal", title = ""), linetype = guide_none()) %+%
  scale_linetype_manual(values = c("TRUE" = 1, "FALSE" = 3))

ggplot(
  data.frame(
    x = rep(xx, 2L),
    fun = rep(c("p'", "q'"), each = length(xx)),
    y = as.numeric(attr(blend_mat, "gradient")),
    relevant = c(xx <= 13, xx >= 7)
  ),
  aes(x = x, y = y, color = fun, linetype = relevant)
) %+%
  geom_line() %+%
  theme_bw() %+%
  theme(
    legend.position = "bottom", legend.box = "horizontal"
  ) %+%
  guides(color = guide_legend(direction = "horizontal", title = ""), linetype = guide_none()) %+%
  scale_linetype_manual(values = c("TRUE" = 1, "FALSE" = 3))

Keras Callback for adaptive learning rate with weight restoration

Description

Provides a keras callback similar to keras3::callback_reduce_lr_on_plateau() but which also restores the weights to the best seen so far whenever a learning rate reduction occurs, and with slightly more restrictive improvement detection.

Usage

callback_adaptive_lr(
  monitor = "val_loss",
  factor = 0.1,
  patience = 10L,
  verbose = 0L,
  mode = c("auto", "min", "max"),
  delta_abs = 1e-04,
  delta_rel = 0,
  cooldown = 0L,
  min_lr = 0,
  restore_weights = TRUE
)

Arguments

monitor

quantity to be monitored.
factor

factor by which the learning rate will be reduced. new_lr = old_lr * factor.
patience

number of epochs with no significant improvement after which the learning rate will be reduced.
verbose

integer. Set to 1 to receive update messages.
mode

Optimisation mode. "auto" detects the mode from the name of monitor. "min" monitors for decreasing metrics. "max" monitors for increasing metrics.
delta_abs

Minimum absolute metric improvement per epoch. The learning rate will be reduced if the average improvement is less than delta_abs per epoch for patience epochs.
delta_rel

Minimum relative metric improvement per epoch. The learning rate will be reduced if the average improvement is less than ⁠|metric| * delta_rel⁠ per epoch for patience epochs.
cooldown

number of epochs to wait before resuming normal operation after learning rate has been reduced. The minimum number of epochs between two learning rate reductions is patience + cooldown.
min_lr

lower bound for the learning rate. If a learning rate reduction would lower the learning rate below min_lr, it will be clipped at min_lr instead and no further reductions will be performed.
restore_weights

Bool. If TRUE, the best weights will be restored at each learning rate reduction. This is very useful if the metric oscillates.

Details

Note that while keras3::callback_reduce_lr_on_plateau() automatically logs the learning rate as a metric 'lr', this is currently impossible from R. Thus, if you want to also log the learning rate, you should add keras3::callback_reduce_lr_on_plateau() with a high min_lr to effectively disable the callback but still monitor the learning rate.

Value

A KerasCallback suitable for passing to keras3::fit().

Examples

dist <- dist_exponential()
group <- sample(c(0, 1), size = 100, replace = TRUE)
x <- dist$sample(100, with_params = list(rate = group + 1))
global_fit <- fit(dist, x)

if (interactive()) {
  library(keras3)
  l_in <- layer_input(shape = 1L)
  mod <- tf_compile_model(
    inputs = list(l_in),
    intermediate_output = l_in,
    dist = dist,
    optimizer = optimizer_adam(),
    censoring = FALSE,
    truncation = FALSE
  )
  tf_initialise_model(mod, global_fit$params)
  fit_history <- fit(
    mod,
    x = as_tensor(group, config_floatx()),
    y = as_trunc_obs(x),
    epochs = 20L,
    callbacks = list(
      callback_adaptive_lr("loss", factor = 0.5, patience = 2L, verbose = 1L, min_lr = 1.0e-4),
      callback_reduce_lr_on_plateau("loss", min_lr = 1.0) # to track lr
    )
  )

  plot(fit_history)

  predicted_means <- predict(mod, data = as_tensor(c(0, 1), config_floatx()))
}

Callback to monitor likelihood gradient components

Description

Provides a keras callback to monitor the individual components of the censored and truncated likelihood. Useful for debugging TensorFlow implementations of Distributions.

Usage

callback_debug_dist_gradients(
  object,
  data,
  obs,
  keep_grads = FALSE,
  stop_on_na = TRUE,
  verbose = TRUE
)

Arguments

object

A reservr_keras_model created by tf_compile_model().
data

Input data for the model.
obs

Observations associated to data.
keep_grads

Log actual gradients? (memory hungry!)
stop_on_na

Stop if any likelihood component as NaN in its gradients?
verbose

Print a message if training is halted? The Message will contain information about which likelihood components have NaN in their gradients.

Value

A KerasCallback suitable for passing to keras3::fit().

Examples

dist <- dist_exponential()
group <- sample(c(0, 1), size = 100, replace = TRUE)
x <- dist$sample(100, with_params = list(rate = group + 1))
global_fit <- fit(dist, x)

if (interactive()) {
  library(keras3)
  l_in <- layer_input(shape = 1L)
  mod <- tf_compile_model(
    inputs = list(l_in),
    intermediate_output = l_in,
    dist = dist,
    optimizer = optimizer_adam(),
    censoring = FALSE,
    truncation = FALSE
  )
  tf_initialise_model(mod, global_fit$params)
  gradient_tracker <- callback_debug_dist_gradients(
    mod,
    as_tensor(group, config_floatx()),
    x,
    keep_grads = TRUE
  )
  fit_history <- fit(
    mod,
    x = as_tensor(group, config_floatx()),
    y = x,
    epochs = 20L,
    callbacks = list(
      callback_adaptive_lr("loss", factor = 0.5, patience = 2L, verbose = 1L, min_lr = 1.0e-4),
      gradient_tracker,
      callback_reduce_lr_on_plateau("loss", min_lr = 1.0) # to track lr
    )
  )
  gradient_tracker$gradient_logs[[20]]$dens

  plot(fit_history)

  predicted_means <- predict(mod, data = as_tensor(c(0, 1), config_floatx()))
}

Construct a BDEGP-Family

Description

Constructs a BDEGP-Family distribution with fixed number of components and blending interval.

Usage

dist_bdegp(n, m, u, epsilon)

Arguments

n

Number of dirac components, starting with a point mass at 0.
m

Number of erlang components, translated by n - 0.5.
u

Blending cut-off, must be a positive real.
epsilon

Blending radius, must be a positive real less than u. The blending interval will be ⁠u - epsilon < x < u + epsilon⁠.

Value

  • A MixtureDistribution of

    • n DiracDistributions at 0 .. n - 1 and

    • a BlendedDistribution object with child Distributions

      • a TranslatedDistribution with offset n - 0.5 of an ErlangMixtureDistribution with m shapes

      • and a GeneralizedParetoDistribution with shape parameter restricted to [0, 1] and location parameter fixed at u With break u and bandwidth epsilon.

See Also

Other Distributions: Distribution, dist_beta(), dist_binomial(), dist_blended(), dist_dirac(), dist_discrete(), dist_empirical(), dist_erlangmix(), dist_exponential(), dist_gamma(), dist_genpareto(), dist_lognormal(), dist_mixture(), dist_negbinomial(), dist_normal(), dist_pareto(), dist_poisson(), dist_translate(), dist_trunc(), dist_uniform(), dist_weibull()

Examples

dist <- dist_bdegp(n = 1, m = 2, u = 10, epsilon = 3)
params <- list(
  dists = list(
    list(),
    list(
      dists = list(
        list(
          dist = list(
            shapes = list(1L, 2L),
            scale = 1.0,
            probs = list(0.7, 0.3)
          )
        ),
        list(
          sigmau = 1.0,
          xi = 0.1
        )
      ),
      probs = list(0.1, 0.9)
    )
  ),
  probs = list(0.95, 0.05)
)
x <- dist$sample(100, with_params = params)

plot_distributions(
  theoretical = dist,
  empirical = dist_empirical(x),
  .x = seq(0, 20, length.out = 101),
  with_params = list(theoretical = params)
)

Beta Distribution

Description

See stats::Beta

Usage

dist_beta(shape1 = NULL, shape2 = NULL, ncp = NULL)

Arguments

shape1

First scalar shape parameter, or NULL as a placeholder.
shape2

Second scalar shape parameter, or NULL as a placeholder.
ncp

Scalar non-centrality parameter, or NULL as a placeholder.

Details

All parameters can be overridden with with_params = list(shape = ..., scale = ...).

Value

A BetaDistribution object.

See Also

Other Distributions: Distribution, dist_bdegp(), dist_binomial(), dist_blended(), dist_dirac(), dist_discrete(), dist_empirical(), dist_erlangmix(), dist_exponential(), dist_gamma(), dist_genpareto(), dist_lognormal(), dist_mixture(), dist_negbinomial(), dist_normal(), dist_pareto(), dist_poisson(), dist_translate(), dist_trunc(), dist_uniform(), dist_weibull()

Examples

d_beta <- dist_beta(shape1 = 2, shape2 = 2, ncp = 0)
x <- d_beta$sample(100)
d_emp <- dist_empirical(x)

plot_distributions(
  empirical = d_emp,
  theoretical = d_beta,
  estimated = d_beta,
  with_params = list(
    estimated = inflate_params(
      fitdistrplus::fitdist(x, distr = "beta")$estimate
    )
  ),
  .x = seq(0, 2, length.out = 100)
)

Binomial Distribution

Description

See stats::Binomial

Usage

dist_binomial(size = NULL, prob = NULL)

Arguments

size

Number of trials parameter (integer), or NULL as a placeholder.
prob

Success probability parameter, or NULL as a placeholder.

Details

Both parameters can be overridden with with_params = list(size = ..., prob = ...).

Value

A BinomialDistribution object.

See Also

Other Distributions: Distribution, dist_bdegp(), dist_beta(), dist_blended(), dist_dirac(), dist_discrete(), dist_empirical(), dist_erlangmix(), dist_exponential(), dist_gamma(), dist_genpareto(), dist_lognormal(), dist_mixture(), dist_negbinomial(), dist_normal(), dist_pareto(), dist_poisson(), dist_translate(), dist_trunc(), dist_uniform(), dist_weibull()

Examples

d_binom <- dist_binomial(size = 10, prob = 0.5)
x <- d_binom$sample(100)
d_emp <- dist_empirical(x)

plot_distributions(
  empirical = d_emp,
  theoretical = d_binom,
  estimated = d_binom,
  with_params = list(
    estimated = list(
      size = max(x),
      prob = mean(x) / max(x)
    )
  ),
  .x = 0:max(x)
)

Blended distribution

Description

Blended distribution

Usage

dist_blended(dists, probs = NULL, breaks = NULL, bandwidths = NULL)

Arguments

dists

A list of k >= 2 component Distributions.
probs

k Mixture weight parameters
breaks

k - 1 Centers of the blending zones. dists[i] will blend into dists[i + 1] around breaks[i].
bandwidths

k - 1 Radii of the blending zones. The i-th blending zone will begin at breaks[i] - bandwidths[i] and end at breaks[i] + bandwidths[i]. A bandwidth of 0 corresponds to a hard cut-off, i.e. a jump discontinuity in the density of the blended Distribution.

Value

A BlendedDistribution object.

See Also

Other Distributions: Distribution, dist_bdegp(), dist_beta(), dist_binomial(), dist_dirac(), dist_discrete(), dist_empirical(), dist_erlangmix(), dist_exponential(), dist_gamma(), dist_genpareto(), dist_lognormal(), dist_mixture(), dist_negbinomial(), dist_normal(), dist_pareto(), dist_poisson(), dist_translate(), dist_trunc(), dist_uniform(), dist_weibull()

Examples

bd <- dist_blended(
  list(
    dist_normal(mean = 0.0, sd = 1.0),
    dist_genpareto(u = 3.0, sigmau = 1.0, xi = 3.0)
  ),
  breaks = list(3.0),
  bandwidths = list(0.5),
  probs = list(0.9, 0.1)
)

plot_distributions(
  bd,
  .x = seq(-3, 10, length.out = 100),
  plots = c("d", "p")
)

Dirac (degenerate point) Distribution

Description

A degenerate distribution with all mass at a single point.

Usage

dist_dirac(point = NULL)

Arguments

point

The point with probability mass 1.

Details

The parameter can be overridden with with_params = list(point = ...).

Value

A DiracDistribution object.

See Also

Other Distributions: Distribution, dist_bdegp(), dist_beta(), dist_binomial(), dist_blended(), dist_discrete(), dist_empirical(), dist_erlangmix(), dist_exponential(), dist_gamma(), dist_genpareto(), dist_lognormal(), dist_mixture(), dist_negbinomial(), dist_normal(), dist_pareto(), dist_poisson(), dist_translate(), dist_trunc(), dist_uniform(), dist_weibull()

Examples

d_dirac <- dist_dirac(1.5)
d_dirac$sample(2L)
d_dirac$sample(2L, list(point = 42.0))

Discrete Distribution

Description

A full-flexibility discrete distribution with values from 1 to size.

Usage

dist_discrete(size = NULL, probs = NULL)

Arguments

size

Number of classes parameter (integer). Required if probs is NULL.
probs

Vector of probabilties parameter, or NULL as a placeholder.

Details

Parameters can be overridden with with_params = list(probs = ...).

Value

A DiscreteDistribution object.

See Also

Other Distributions: Distribution, dist_bdegp(), dist_beta(), dist_binomial(), dist_blended(), dist_dirac(), dist_empirical(), dist_erlangmix(), dist_exponential(), dist_gamma(), dist_genpareto(), dist_lognormal(), dist_mixture(), dist_negbinomial(), dist_normal(), dist_pareto(), dist_poisson(), dist_translate(), dist_trunc(), dist_uniform(), dist_weibull()

Examples

d_discrete <- dist_discrete(probs = list(0.5, 0.25, 0.15, 0.1))
x <- d_discrete$sample(100)
d_emp <- dist_empirical(x)

plot_distributions(
  empirical = d_emp,
  theoretical = d_discrete,
  estimated = d_discrete,
  with_params = list(
    estimated = list(
      size = max(x),
      probs = as.list(unname(table(x)) / 100)
    )
  ),
  .x = 0:max(x)
)

Empirical distribution

Description

Creates an empirical distribution object from a sample. Assumes iid. samples. with_params should not be used with this distribution because estimation of the relevant indicators happens during construction.

Usage

dist_empirical(sample, positive = FALSE, bw = "nrd0")

Arguments

sample

Sample to build the empirical distribution from
positive

Is the underlying distribution known to be positive? This will effect the density estimation procedure. positive = FALSE uses a kernel density estimate produced by density(), positive = TRUE uses a log-kernel density estimate produced by logKDE::logdensity_fft(). The latter can improve density estimation near zero.
bw

Bandwidth parameter for density estimation. Passed to the density estimation function selected by positive.

Details

  • sample() samples iid. from sample. This approach is similar to bootstrapping.

  • density() evaluates a kernel density estimate, approximating with zero outside of the known support. This estimate is either obtained using stats::density or logKDE::logdensity_fft, depending on positive.

  • probability() evaluates the empirical cumulative density function obtained by stats::ecdf.

  • quantile() evaluates the empirical quantiles using stats::quantile

  • hazard() estimates the hazard rate using the density estimate and the empirical cumulative density function: h(t) = df(t) / (1 - cdf(t)).

Value

An EmpiricalDistribution object.

See Also

Other Distributions: Distribution, dist_bdegp(), dist_beta(), dist_binomial(), dist_blended(), dist_dirac(), dist_discrete(), dist_erlangmix(), dist_exponential(), dist_gamma(), dist_genpareto(), dist_lognormal(), dist_mixture(), dist_negbinomial(), dist_normal(), dist_pareto(), dist_poisson(), dist_translate(), dist_trunc(), dist_uniform(), dist_weibull()

Examples

x <- rexp(20, rate = 1)
dx <- dist_empirical(sample = x, positive = TRUE)

y <- rnorm(20)
dy <- dist_empirical(sample = y)

plot_distributions(
  exponential = dx,
  normal = dy,
  .x = seq(-3, 3, length.out = 100)
)

Erlang Mixture distribution

Description

Erlang Mixture distribution

Usage

dist_erlangmix(shapes, scale = NULL, probs = NULL)

Arguments

shapes

Shape parameters, a trunc_erlangmix fit, or NULL as a placeholder.
scale

Common scale parameter, or NULL as a placeholder.
probs

Mixing probabilities, or NULL as a placeholder.

Value

An ErlangMixtureDistribution object.

See Also

Other Distributions: Distribution, dist_bdegp(), dist_beta(), dist_binomial(), dist_blended(), dist_dirac(), dist_discrete(), dist_empirical(), dist_exponential(), dist_gamma(), dist_genpareto(), dist_lognormal(), dist_mixture(), dist_negbinomial(), dist_normal(), dist_pareto(), dist_poisson(), dist_translate(), dist_trunc(), dist_uniform(), dist_weibull()

Examples

params <- list(scale = 1.0, probs = list(0.5, 0.3, 0.2), shapes = list(1L, 2L, 3L))
dist <- dist_erlangmix(vector("list", 3L))
x <- dist$sample(20, with_params = params)
d_emp <- dist_empirical(x, positive = TRUE)

plot_distributions(
  empirical = d_emp,
  theoretical = dist,
  with_params = list(
    theoretical = params
  ),
  .x = seq(1e-4, 5, length.out = 100)
)

Exponential distribution

Description

See stats::Exponential.

Usage

dist_exponential(rate = NULL)

Arguments

rate

Scalar rate parameter, or NULL as a placeholder.

Details

The parameter can be overridden with with_params = list(rate = ...).

Value

An ExponentialDistribution object.

See Also

Other Distributions: Distribution, dist_bdegp(), dist_beta(), dist_binomial(), dist_blended(), dist_dirac(), dist_discrete(), dist_empirical(), dist_erlangmix(), dist_gamma(), dist_genpareto(), dist_lognormal(), dist_mixture(), dist_negbinomial(), dist_normal(), dist_pareto(), dist_poisson(), dist_translate(), dist_trunc(), dist_uniform(), dist_weibull()

Examples

rate <- 1
d_exp <- dist_exponential()
x <- d_exp$sample(20, with_params = list(rate = rate))
d_emp <- dist_empirical(x, positive = TRUE)

plot_distributions(
  empirical = d_emp,
  theoretical = d_exp,
  estimated = d_exp,
  with_params = list(
    theoretical = list(rate = rate),
    estimated = list(rate = 1 / mean(x))
  ),
  .x = seq(1e-4, 5, length.out = 100)
)

Gamma distribution

Description

See stats::GammaDist.

Usage

dist_gamma(shape = NULL, rate = NULL)

Arguments

shape

Scalar shape parameter, or NULL as a placeholder.
rate

Scalar rate parameter, or NULL as a placeholder.

Details

Both parameters can be overridden with with_params = list(shape = ..., rate = ...).

Value

A GammaDistribution object.

See Also

Other Distributions: Distribution, dist_bdegp(), dist_beta(), dist_binomial(), dist_blended(), dist_dirac(), dist_discrete(), dist_empirical(), dist_erlangmix(), dist_exponential(), dist_genpareto(), dist_lognormal(), dist_mixture(), dist_negbinomial(), dist_normal(), dist_pareto(), dist_poisson(), dist_translate(), dist_trunc(), dist_uniform(), dist_weibull()

Examples

alpha <- 2
beta <- 2

d_gamma <- dist_gamma(shape = alpha, rate = beta)
x <- d_gamma$sample(100)
d_emp <- dist_empirical(x, positive = TRUE)

plot_distributions(
  empirical = d_emp,
  theoretical = d_gamma,
  estimated = d_gamma,
  with_params = list(
    estimated = inflate_params(
      fitdistrplus::fitdist(x, distr = "gamma")$estimate
    )
  ),
  .x = seq(1e-3, max(x), length.out = 100)
)

Generalized Pareto Distribution

Description

See evmix::gpd

Usage

dist_genpareto(u = NULL, sigmau = NULL, xi = NULL)

dist_genpareto1(u = NULL, sigmau = NULL, xi = NULL)

Arguments

u

Scalar location parameter, or NULL as a placeholder.
sigmau

Scalar scale parameter, or NULL as a placeholder.
xi

Scalar shape parameter, or NULL as a placeholder.

Details

All parameters can be overridden with with_params = list(u = ..., sigmau = ..., xi = ...).

dist_genpareto1 is equivalent to dist_genpareto but enforces bound constraints on xi to ⁠[0, 1]⁠. This ensures unboundedness and finite expected value unless xi == 1.0.

Value

A GeneralizedParetoDistribution object.

See Also

Other Distributions: Distribution, dist_bdegp(), dist_beta(), dist_binomial(), dist_blended(), dist_dirac(), dist_discrete(), dist_empirical(), dist_erlangmix(), dist_exponential(), dist_gamma(), dist_lognormal(), dist_mixture(), dist_negbinomial(), dist_normal(), dist_pareto(), dist_poisson(), dist_translate(), dist_trunc(), dist_uniform(), dist_weibull()

Examples

d_genpareto <- dist_genpareto(u = 0, sigmau = 1, xi = 1)
x <- d_genpareto$sample(100)
d_emp <- dist_empirical(x)

d_genpareto$export_functions("gpd") # so fitdistrplus finds it

plot_distributions(
  empirical = d_emp,
  theoretical = d_genpareto,
  estimated = d_genpareto,
  with_params = list(
    estimated = fit(dist_genpareto(), x)$params
  ),
  .x = seq(0, 5, length.out = 100)
)

Log Normal distribution

Description

See stats::Lognormal.

Usage

dist_lognormal(meanlog = NULL, sdlog = NULL)

Arguments

meanlog

Scalar mean parameter on the log scale, or NULL as a placeholder.
sdlog

Scalar standard deviation parameter on the log scale, or NULL as a placeholder.

Details

Both parameters can be overridden with with_params = list(meanlog = ..., sdlog = ...).

Value

A LognormalDistribution object.

See Also

Other Distributions: Distribution, dist_bdegp(), dist_beta(), dist_binomial(), dist_blended(), dist_dirac(), dist_discrete(), dist_empirical(), dist_erlangmix(), dist_exponential(), dist_gamma(), dist_genpareto(), dist_mixture(), dist_negbinomial(), dist_normal(), dist_pareto(), dist_poisson(), dist_translate(), dist_trunc(), dist_uniform(), dist_weibull()

Examples

mu <- 0
sigma <- 1

d_lnorm <- dist_lognormal(meanlog = mu, sdlog = sigma)
x <- d_lnorm$sample(20)
d_emp <- dist_empirical(x, positive = TRUE)

plot_distributions(
  empirical = d_emp,
  theoretical = d_lnorm,
  estimated = d_lnorm,
  with_params = list(
    estimated = inflate_params(
      fitdistrplus::fitdist(x, distr = "lnorm")$estimate
    )
  ),
  .x = seq(1e-3, 5, length.out = 100)
)

Mixture distribution

Description

Parameters of mixing components can be overridden with with_params = list(dists = list(..., ..., ...)). #' Mixing probabilites can be overridden with with_params = list(probs = list(..., ..., ...)). The number of components cannot be overridden.

Usage

dist_mixture(dists = list(), probs = NULL)

Arguments

dists

A list of mixing distributions. May contain placeholders and duplicates.
probs

A list of mixing probabilities with the same length as dists. They are normalized to sum to one and NULL can be used as a placeholder within probs. To reduce the number of required parameters, probs should at least be partly specified (probs = list(NULL, NULL, ..., 1) with k - 1 NULLs where k is the number of mixing components).

Details

Does not support the quantile() capability!

Value

A MixtureDistribution object.

See Also

Other Distributions: Distribution, dist_bdegp(), dist_beta(), dist_binomial(), dist_blended(), dist_dirac(), dist_discrete(), dist_empirical(), dist_erlangmix(), dist_exponential(), dist_gamma(), dist_genpareto(), dist_lognormal(), dist_negbinomial(), dist_normal(), dist_pareto(), dist_poisson(), dist_translate(), dist_trunc(), dist_uniform(), dist_weibull()

Examples

# A complicated way to define a uniform distribution on \[0, 2\]
dist_mixture(
  dists = list(
    dist_uniform(min = 0, max = 1),
    dist_uniform(min = 1, max = 2)
  ),
  probs = list(0.5, 0.5)
)

Negative binomial Distribution

Description

See stats::NegBinomial

Usage

dist_negbinomial(size = NULL, mu = NULL)

Arguments

size

Number of successful trials parameter, or NULL as a placeholder. Non-integer values > 0 are allowed.
mu

Mean parameter, or NULL as a placeholder.

Details

Both parameters can be overridden with with_params = list(size = ..., prob = ...).

Value

A NegativeBinomialDistribution object.

See Also

Other Distributions: Distribution, dist_bdegp(), dist_beta(), dist_binomial(), dist_blended(), dist_dirac(), dist_discrete(), dist_empirical(), dist_erlangmix(), dist_exponential(), dist_gamma(), dist_genpareto(), dist_lognormal(), dist_mixture(), dist_normal(), dist_pareto(), dist_poisson(), dist_translate(), dist_trunc(), dist_uniform(), dist_weibull()

Examples

d_nbinom <- dist_negbinomial(size = 3.5, mu = 8.75)
x <- d_nbinom$sample(100)
d_emp <- dist_empirical(x)

plot_distributions(
  empirical = d_emp,
  theoretical = d_nbinom,
  estimated = d_nbinom,
  with_params = list(
    estimated = inflate_params(
      fitdistrplus::fitdist(x, distr = "nbinom")$estimate
    )
  ),
  .x = 0:max(x)
)

Normal distribution

Description

See stats::Normal.

Usage

dist_normal(mean = NULL, sd = NULL)

Arguments

mean

Scalar mean parameter, or NULL as a placeholder.
sd

Scalar standard deviation parameter, or NULL as a placeholder.

Details

Both parameters can be overridden with with_params = list(mean = ..., sd = ...).

Value

A NormalDistribution object.

See Also

Other Distributions: Distribution, dist_bdegp(), dist_beta(), dist_binomial(), dist_blended(), dist_dirac(), dist_discrete(), dist_empirical(), dist_erlangmix(), dist_exponential(), dist_gamma(), dist_genpareto(), dist_lognormal(), dist_mixture(), dist_negbinomial(), dist_pareto(), dist_poisson(), dist_translate(), dist_trunc(), dist_uniform(), dist_weibull()

Examples

mu <- 0
sigma <- 1

d_norm <- dist_normal(mean = mu, sd = sigma)
x <- d_norm$sample(20)
d_emp <- dist_empirical(x)

plot_distributions(
  empirical = d_emp,
  theoretical = d_norm,
  estimated = d_norm,
  with_params = list(
    estimated = list(mean = mean(x), sd = sd(x))
  ),
  .x = seq(-3, 3, length.out = 100)
)

Pareto Distribution

Description

See Pareto

Usage

dist_pareto(shape = NULL, scale = NULL)

Arguments

shape

Scalar shape parameter, or NULL as a placeholder.
scale

Scalar scale parameter, or NULL as a placeholder.

Details

Both parameters can be overridden with with_params = list(shape = ..., scale = ...).

Value

A ParetoDistribution object.

See Also

Other Distributions: Distribution, dist_bdegp(), dist_beta(), dist_binomial(), dist_blended(), dist_dirac(), dist_discrete(), dist_empirical(), dist_erlangmix(), dist_exponential(), dist_gamma(), dist_genpareto(), dist_lognormal(), dist_mixture(), dist_negbinomial(), dist_normal(), dist_poisson(), dist_translate(), dist_trunc(), dist_uniform(), dist_weibull()

Examples

d_pareto <- dist_pareto(shape = 3, scale = 1)
x <- d_pareto$sample(100)
d_emp <- dist_empirical(x)

plot_distributions(
  empirical = d_emp,
  theoretical = d_pareto,
  estimated = d_pareto,
  with_params = list(
    estimated = inflate_params(
      fitdistrplus::fitdist(x, distr = "pareto")$estimate
    )
  ),
  .x = seq(0, 2, length.out = 100)
)

Poisson Distribution

Description

See stats::Poisson

Usage

dist_poisson(lambda = NULL)

Arguments

lambda

Scalar rate parameter, or NULL as a placeholder.

Details

The parameter can be overridden with with_params = list(lambda = ...).

Value

A PoissonDistribution object.

See Also

Other Distributions: Distribution, dist_bdegp(), dist_beta(), dist_binomial(), dist_blended(), dist_dirac(), dist_discrete(), dist_empirical(), dist_erlangmix(), dist_exponential(), dist_gamma(), dist_genpareto(), dist_lognormal(), dist_mixture(), dist_negbinomial(), dist_normal(), dist_pareto(), dist_translate(), dist_trunc(), dist_uniform(), dist_weibull()

Examples

d_pois <- dist_poisson(lambda = 5.0)
x <- d_pois$sample(100)
d_emp <- dist_empirical(x)

plot_distributions(
  empirical = d_emp,
  theoretical = d_pois,
  estimated = d_pois,
  with_params = list(
    estimated = inflate_params(
      fitdistrplus::fitdist(x, distr = "pois")$estimate
    )
  ),
  .x = 0:max(x)
)

Tranlsated distribution

Description

Tranlsated distribution

Usage

dist_translate(dist = NULL, offset = NULL, multiplier = 1)

Arguments

dist

An underlying distribution, or NULL as a placeholder.
offset

Offset to be added to each observation, or NULL as a placeholder.
multiplier

Factor to multiply each observation by, or NULL as a placeholder.

Value

A TranslatedDistribution object.

See Also

Other Distributions: Distribution, dist_bdegp(), dist_beta(), dist_binomial(), dist_blended(), dist_dirac(), dist_discrete(), dist_empirical(), dist_erlangmix(), dist_exponential(), dist_gamma(), dist_genpareto(), dist_lognormal(), dist_mixture(), dist_negbinomial(), dist_normal(), dist_pareto(), dist_poisson(), dist_trunc(), dist_uniform(), dist_weibull()

Examples

d_norm <- dist_normal(mean = 0, sd = 1)
d_tnorm <- dist_translate(dist = d_norm, offset = 1)
plot_distributions(d_norm, d_tnorm, .x = seq(-2, 3, length.out = 100))

Truncated distribution

Description

Truncated distribution

Usage

dist_trunc(dist = NULL, min = NULL, max = NULL, offset = 0, max_retry = 100)

Arguments

dist

An underlying distribution, or NULL as a placeholder.
min

Minimum value to truncate at (exclusive), or NULL as a placeholder.
max

Maxmimum value to truncate at (inclusive), or NULL as a placeholder.
offset

Offset to be added to each observation after truncation, or NULL as a placeholder. Truncation of dist will occur to (min, max]. The offset is then added deterministically.
max_retry

Maximum number of resample attempts when trying to sample with rejection.

Value

A TruncatedDistribution object.

See Also

Other Distributions: Distribution, dist_bdegp(), dist_beta(), dist_binomial(), dist_blended(), dist_dirac(), dist_discrete(), dist_empirical(), dist_erlangmix(), dist_exponential(), dist_gamma(), dist_genpareto(), dist_lognormal(), dist_mixture(), dist_negbinomial(), dist_normal(), dist_pareto(), dist_poisson(), dist_translate(), dist_uniform(), dist_weibull()

Examples

d_norm <- dist_normal(mean = 0, sd = 1)
d_tnorm <- dist_trunc(dist = d_norm, min = -2, max = 2, offset = 1)
plot_distributions(d_norm, d_tnorm, .x = seq(-2, 3, length.out = 100))

Uniform distribution

Description

See stats::Uniform

Usage

dist_uniform(min = NULL, max = NULL)

Arguments

min

Lower limit, or NULL as a placeholder.
max

Upper limit, or NULL as a placeholder.

Details

Both parameters can be overridden with with_params = list(min = ..., max = ...).

Value

A UniformDistribution object.

See Also

Other Distributions: Distribution, dist_bdegp(), dist_beta(), dist_binomial(), dist_blended(), dist_dirac(), dist_discrete(), dist_empirical(), dist_erlangmix(), dist_exponential(), dist_gamma(), dist_genpareto(), dist_lognormal(), dist_mixture(), dist_negbinomial(), dist_normal(), dist_pareto(), dist_poisson(), dist_translate(), dist_trunc(), dist_weibull()

Examples

d_unif <- dist_uniform(min = 0, max = 1)
x <- d_unif$sample(100)
d_emp <- dist_empirical(x)

plot_distributions(
  empirical = d_emp,
  theoretical = d_unif,
  estimated = d_unif,
  with_params = list(
    estimated = inflate_params(
      fitdistrplus::fitdist(x, distr = "unif")$estimate
    )
  ),
  .x = seq(0, 1, length.out = 100)
)

Weibull Distribution

Description

See stats::Weibull

Usage

dist_weibull(shape = NULL, scale = NULL)

Arguments

shape

Scalar shape parameter, or NULL as a placeholder.
scale

Scalar scale parameter, or NULL as a placeholder.

Details

Both parameters can be overridden with with_params = list(shape = ..., scale = ...).

Value

A WeibullDistribution object.

See Also

Other Distributions: Distribution, dist_bdegp(), dist_beta(), dist_binomial(), dist_blended(), dist_dirac(), dist_discrete(), dist_empirical(), dist_erlangmix(), dist_exponential(), dist_gamma(), dist_genpareto(), dist_lognormal(), dist_mixture(), dist_negbinomial(), dist_normal(), dist_pareto(), dist_poisson(), dist_translate(), dist_trunc(), dist_uniform()

Examples

d_weibull <- dist_weibull(shape = 3, scale = 1)
x <- d_weibull$sample(100)
d_emp <- dist_empirical(x)

plot_distributions(
  empirical = d_emp,
  theoretical = d_weibull,
  estimated = d_weibull,
  with_params = list(
    estimated = inflate_params(
      fitdistrplus::fitdist(x, distr = "weibull")$estimate
    )
  ),
  .x = seq(0, 2, length.out = 100)
)

Base class for Distributions

Description

Represents a modifiable Distribution family

Active bindings

default_params

Get or set (non-recursive) default parameters of a Distribution

param_bounds

Get or set (non-recursive) parameter bounds (box constraints) of a Distribution

Methods

Public methods

Method new()

Usage
Distribution$new(type, caps, params, name, default_params)
Arguments
type

Type of distribution. This is a string constant for the default implementation. Distributions with non-constant type must override the get_type() function.

caps

Character vector of capabilities to fuel the default implementations of has_capability() and require_capability(). Distributions with dynamic capabilities must override the has_capability() function.

params

Initial parameter bounds structure, backing the param_bounds active binding (usually a list of intervals).

name

Name of the Distribution class. Should be CamelCase and end with "Distribution".

default_params

Initial fixed parameters backing the default_params active binding (usually a list of numeric / NULLs).

Details

Construct a Distribution instance

Used internally by the ⁠dist_*⁠ functions.

Method sample()

Usage
Distribution$sample(n, with_params = list())
Arguments
n

number of samples to draw.

with_params

Distribution parameters to use. Each parameter value can also be a numeric vector of length n. In that case the i-th sample will use the i-th parameters.

Details

Sample from a Distribution

Returns

A length n vector of i.i.d. random samples from the Distribution with the specified parameters.

Examples
dist_exponential(rate = 2.0)$sample(10)

Method density()

Usage
Distribution$density(x, log = FALSE, with_params = list())
Arguments
x

Vector of points to evaluate the density at.

log

Flag. If TRUE, return the log-density instead.

with_params

Distribution parameters to use. Each parameter value can also be a numeric vector of length length(x). In that case, the i-th density point will use the i-th parameters.

Details

Density of a Distribution

Returns

A numeric vector of (log-)densities

Examples
dist_exponential()$density(c(1.0, 2.0), with_params = list(rate = 2.0))

Method tf_logdensity()

Usage
Distribution$tf_logdensity()
Details

Compile a TensorFlow function for log-density evaluation

Returns

A tf_function taking arguments x and args returning the log-density of the Distribution evaluated at x with parameters args.

Method probability()

Usage
Distribution$probability(
  q,
  lower.tail = TRUE,
  log.p = FALSE,
  with_params = list()
)
Arguments
q

Vector of points to evaluate the probability function at.

lower.tail

If TRUE, return P(X <= q). Otherwise return P(X > q).

log.p

If TRUE, probabilities are returned as log(p).

with_params

Distribution parameters to use. Each parameter value can also be a numeric vector of length length(q). In that case, the i-th probability point will use the i-th parameters.

Details

Cumulative probability of a Distribution

Returns

A numeric vector of (log-)probabilities

Examples
dist_exponential()$probability(
  c(1.0, 2.0),
  with_params = list(rate = 2.0)
)

Method tf_logprobability()

Usage
Distribution$tf_logprobability()
Details

Compile a TensorFlow function for log-probability evaluation

Returns

A tf_function taking arguments qmin, qmax and args returning the log-probability of the Distribution evaluated over the closed interval [qmin, qmax] with parameters args.

Method quantile()

Usage
Distribution$quantile(
  p,
  lower.tail = TRUE,
  log.p = FALSE,
  with_params = list()
)
Arguments
p

Vector of probabilities.

lower.tail

If TRUE, return P(X <= q). Otherwise return P(X > q).

log.p

If TRUE, probabilities are returned as log(p).

with_params

Distribution parameters to use. Each parameter value can also be a numeric vector of length length(p). In that case, the i-th quantile will use the i-th parameters.

Details

Quantile function of a Distribution

Returns

A numeric vector of quantiles

Examples
dist_exponential()$quantile(c(0.1, 0.5), with_params = list(rate = 2.0))

Method hazard()

Usage
Distribution$hazard(x, log = FALSE, with_params = list())
Arguments
x

Vector of points.

log

Flag. If TRUE, return the log-hazard instead.

with_params

Distribution parameters to use. Each parameter value can also be a numeric vector of length length(x). In that case, the i-th hazard point will use the i-th parameters.

Details

Hazard function of a Distribution

Returns

A numeric vector of (log-)hazards

Examples
dist_exponential(rate = 2.0)$hazard(c(1.0, 2.0))

Method diff_density()

Usage
Distribution$diff_density(x, log = FALSE, with_params = list())
Arguments
x

Vector of points.

log

Flag. If TRUE, return the gradient of the log-density instead.

with_params

Distribution parameters to use. Each parameter value can also be a numeric vector of length length(x). In that case, the i-th density point will use the i-th parameters.

Details

Gradients of the density of a Distribution

Returns

A list structure containing the (log-)density gradients of all free parameters of the Distribution evaluated at x.

Examples
dist_exponential()$diff_density(
  c(1.0, 2.0),
  with_params = list(rate = 2.0)
)

Method diff_probability()

Usage
Distribution$diff_probability(
  q,
  lower.tail = TRUE,
  log.p = FALSE,
  with_params = list()
)
Arguments
q

Vector of points to evaluate the probability function at.

lower.tail

If TRUE, return P(X <= q). Otherwise return P(X > q).

log.p

If TRUE, probabilities are returned as log(p).

with_params

Distribution parameters to use. Each parameter value can also be a numeric vector of length length(q). In that case, the i-th probability point will use the i-th parameters.

Details

Gradients of the cumulative probability of a Distribution

Returns

A list structure containing the cumulative (log-)probability gradients of all free parameters of the Distribution evaluated at q.

Examples
dist_exponential()$diff_probability(
  c(1.0, 2.0),
  with_params = list(rate = 2.0)
)

Method is_in_support()

Usage
Distribution$is_in_support(x, with_params = list())
Arguments
x

Vector of points

with_params

Distribution parameters to use. Each parameter value can also be a numeric vector of length length(x). In that case, the i-th point will use the i-th parameters.

Details

Determine if a value is in the support of a Distribution

Returns

A logical vector with the same length as x indicating whether x is part of the support of the distribution given its parameters.

Examples
dist_exponential(rate = 1.0)$is_in_support(c(-1.0, 0.0, 1.0))

Method is_discrete_at()

Usage
Distribution$is_discrete_at(x, with_params = list())
Arguments
x

Vector of points

with_params

Distribution parameters to use. Each parameter value can also be a numeric vector of length length(x). In that case, the i-th point will use the i-th parameters.

Details

Determine if a value has positive probability

Returns

A logical vector with the same length as x indicating whether there is a positive probability mass at x given the Distribution parameters.

Examples
dist_dirac(point = 0.0)$is_discrete_at(c(0.0, 1.0))

Method tf_is_discrete_at()

Usage
Distribution$tf_is_discrete_at()
Details

Compile a TensorFlow function for discrete support checking

Returns

A tf_function taking arguments x and args returning whether the Distribution has a point mass at x given parameters args.

Method has_capability()

Usage
Distribution$has_capability(caps)
Arguments
caps

Character vector of capabilities

Details

Check if a capability is present

Returns

A logical vector the same length as caps.

Examples
dist_exponential()$has_capability("density")

Method get_type()

Usage
Distribution$get_type()
Details

Get the type of a Distribution. Type can be one of discrete, continuous or mixed.

Returns

A string representing the type of the Distribution.

Examples
dist_exponential()$get_type()
dist_dirac()$get_type()

dist_mixture(list(dist_dirac(), dist_exponential()))$get_type()
dist_mixture(list(dist_dirac(), dist_binomial()))$get_type()

Method get_components()

Usage
Distribution$get_components()
Details

Get the component Distributions of a transformed Distribution.

Returns

A possibly empty list of Distributions

Examples
dist_trunc(dist_exponential())$get_components()
dist_dirac()$get_components()
dist_mixture(list(dist_exponential(), dist_gamma()))$get_components()

Method is_discrete()

Usage
Distribution$is_discrete()
Details

Check if a Distribution is discrete, i.e. it has a density with respect to the counting measure.

Returns

TRUE if the Distribution is discrete, FALSE otherwise. Note that mixed distributions are not discrete but can have point masses.

Examples
dist_exponential()$is_discrete()
dist_dirac()$is_discrete()

Method is_continuous()

Usage
Distribution$is_continuous()
Details

Check if a Distribution is continuous, i.e. it has a density with respect to the Lebesgue measure.

Returns

TRUE if the Distribution is continuous, FALSE otherwise. Note that mixed distributions are not continuous.

Examples
dist_exponential()$is_continuous()
dist_dirac()$is_continuous()

Method require_capability()

Usage
Distribution$require_capability(
  caps,
  fun_name = paste0(sys.call(-1)[[1]], "()")
)
Arguments
caps

Character vector of Capabilities to require

fun_name

Frienly text to use for generating the error message in case of failure.

Details

Ensure that a Distribution has all required capabilities. Will throw an error if any capability is missing.

Returns

Invisibly TRUE.

Examples
dist_exponential()$require_capability("diff_density")

Method get_dof()

Usage
Distribution$get_dof()
Details

Get the number of degrees of freedom of a Distribution family. Only parameters without a fixed default are considered free.

Returns

An integer representing the degrees of freedom suitable e.g. for AIC calculations.

Examples
dist_exponential()$get_dof()
dist_exponential(rate = 1.0)$get_dof()

Method get_placeholders()

Usage
Distribution$get_placeholders()
Details

Get Placeholders of a Distribution family. Returns a list of free parameters of the family. Their values will be NULL.

If the Distribution has Distributions as parameters, placeholders will be computed recursively.

Returns

A named list containing any combination of (named or unnamed) lists and NULLs.

Examples
dist_exponential()$get_placeholders()
dist_mixture(list(dist_dirac(), dist_exponential()))$get_placeholders()

Method get_params()

Usage
Distribution$get_params(with_params = list())
Arguments
with_params

Optional parameter overrides with the same structure as dist$get_params(). Given Parameter values are expected to be length 1.

Details

Get a full list of parameters, possibly including placeholders.

Returns

A list representing the (recursive) parameter structure of the Distribution with values for specified parameters and NULL for free parameters that are missing both in the Distributions parameters and in with_params.

Examples
dist_mixture(list(dist_dirac(), dist_exponential()))$get_params(
  with_params = list(probs = list(0.5, 0.5))
)

Method tf_make_constants()

Usage
Distribution$tf_make_constants(with_params = list())
Arguments
with_params

Optional parameter overrides with the same structure as dist$tf_make_constants(). Given Parameter values are expected to be length 1.

Details

Get a list of constant TensorFlow parameters

Returns

A list representing the (recursive) constant parameters of the Distribution with values sprecified by parameters. Each constant is a TensorFlow Tensor of dtype floatx.

Method tf_compile_params()

Usage
Distribution$tf_compile_params(input, name_prefix = "")
Arguments
input

A keras layer to bind all outputs to

name_prefix

Prefix to use for layer names

Details

Compile distribution parameters into tensorflow outputs

Returns

A list with two elements

  • outputs a flat list of keras output layers, one for each parameter.

  • output_inflater a function taking keras output layers and transforming them into a list structure suitable for passing to the loss function returned by tf_compile_model()

Method get_param_bounds()

Usage
Distribution$get_param_bounds()
Details

Get Interval bounds on all Distribution parameters

Returns

A list representing the free (recursive) parameter structure of the Distribution with Interval objects as values representing the bounds of the respective free parameters.

Examples
dist_mixture(
  list(dist_dirac(), dist_exponential()),
  probs = list(0.5, 0.5)
)$get_param_bounds()

dist_mixture(
  list(dist_dirac(), dist_exponential())
)$get_param_bounds()

dist_genpareto()$get_param_bounds()
dist_genpareto1()$get_param_bounds()

Method get_param_constraints()

Usage
Distribution$get_param_constraints()
Details

Get additional (non-linear) equality constraints on Distribution parameters

Returns

NULL if the box constraints specified by dist$get_param_bounds() are sufficient, or a function taking full Distribution parameters and returning either a numeric vector (which must be 0 for valid parameter combinations) or a list with elements

  • constraints: The numeric vector of constraints

  • jacobian: The Jacobi matrix of the constraints with respect to the parameters

Examples
dist_mixture(
  list(dist_dirac(), dist_exponential())
)$get_param_constraints()

Method export_functions()

Usage
Distribution$export_functions(
  name,
  envir = parent.frame(),
  with_params = list()
)
Arguments
name

common suffix of the exported functions

envir

Environment to export the functions to

with_params

Optional list of parameters to use as default values for the exported functions

Details

Export sampling, density, probability and quantile functions to plain R functions

Creates new functions in envir named ⁠{r,d,p,q}<name>⁠ which implement dist$sample, dist$density, dist$probability and dist$quantile as plain functions with default arguments specified by with_params or the fixed parameters.

The resulting functions will have signatures taking all parameters as separate arguments.

Returns

Invisibly NULL.

Examples
tmp_env <- new.env(parent = globalenv())
dist_exponential()$export_functions(
  name = "exp",
  envir = tmp_env,
  with_params = list(rate = 2.0)
)
evalq(
  fitdistrplus::fitdist(rexp(100), "exp"),
  envir = tmp_env
)

Method clone()

The objects of this class are cloneable with this method.

Usage
Distribution$clone(deep = FALSE)
Arguments
deep

Whether to make a deep clone.

See Also

Other Distributions: dist_bdegp(), dist_beta(), dist_binomial(), dist_blended(), dist_dirac(), dist_discrete(), dist_empirical(), dist_erlangmix(), dist_exponential(), dist_gamma(), dist_genpareto(), dist_lognormal(), dist_mixture(), dist_negbinomial(), dist_normal(), dist_pareto(), dist_poisson(), dist_translate(), dist_trunc(), dist_uniform(), dist_weibull()

Examples

# Example for param_bounds:

# Create an Exponential Distribution with rate constrained to (0, 2)
# instead of (0, Inf)
my_exp <- dist_exponential()
my_exp$param_bounds$rate <- interval(c(0, 2))
my_exp$get_param_bounds()

fit_dist(my_exp, rexp(100, rate = 3), start = list(rate = 1))$params$rate


## ------------------------------------------------
## Method `Distribution$sample`
## ------------------------------------------------

dist_exponential(rate = 2.0)$sample(10)

## ------------------------------------------------
## Method `Distribution$density`
## ------------------------------------------------

dist_exponential()$density(c(1.0, 2.0), with_params = list(rate = 2.0))

## ------------------------------------------------
## Method `Distribution$probability`
## ------------------------------------------------

dist_exponential()$probability(
  c(1.0, 2.0),
  with_params = list(rate = 2.0)
)

## ------------------------------------------------
## Method `Distribution$quantile`
## ------------------------------------------------

dist_exponential()$quantile(c(0.1, 0.5), with_params = list(rate = 2.0))

## ------------------------------------------------
## Method `Distribution$hazard`
## ------------------------------------------------

dist_exponential(rate = 2.0)$hazard(c(1.0, 2.0))

## ------------------------------------------------
## Method `Distribution$diff_density`
## ------------------------------------------------

dist_exponential()$diff_density(
  c(1.0, 2.0),
  with_params = list(rate = 2.0)
)

## ------------------------------------------------
## Method `Distribution$diff_probability`
## ------------------------------------------------

dist_exponential()$diff_probability(
  c(1.0, 2.0),
  with_params = list(rate = 2.0)
)

## ------------------------------------------------
## Method `Distribution$is_in_support`
## ------------------------------------------------

dist_exponential(rate = 1.0)$is_in_support(c(-1.0, 0.0, 1.0))

## ------------------------------------------------
## Method `Distribution$is_discrete_at`
## ------------------------------------------------

dist_dirac(point = 0.0)$is_discrete_at(c(0.0, 1.0))

## ------------------------------------------------
## Method `Distribution$has_capability`
## ------------------------------------------------

dist_exponential()$has_capability("density")

## ------------------------------------------------
## Method `Distribution$get_type`
## ------------------------------------------------

dist_exponential()$get_type()
dist_dirac()$get_type()

dist_mixture(list(dist_dirac(), dist_exponential()))$get_type()
dist_mixture(list(dist_dirac(), dist_binomial()))$get_type()

## ------------------------------------------------
## Method `Distribution$get_components`
## ------------------------------------------------

dist_trunc(dist_exponential())$get_components()
dist_dirac()$get_components()
dist_mixture(list(dist_exponential(), dist_gamma()))$get_components()

## ------------------------------------------------
## Method `Distribution$is_discrete`
## ------------------------------------------------

dist_exponential()$is_discrete()
dist_dirac()$is_discrete()

## ------------------------------------------------
## Method `Distribution$is_continuous`
## ------------------------------------------------

dist_exponential()$is_continuous()
dist_dirac()$is_continuous()

## ------------------------------------------------
## Method `Distribution$require_capability`
## ------------------------------------------------

dist_exponential()$require_capability("diff_density")

## ------------------------------------------------
## Method `Distribution$get_dof`
## ------------------------------------------------

dist_exponential()$get_dof()
dist_exponential(rate = 1.0)$get_dof()

## ------------------------------------------------
## Method `Distribution$get_placeholders`
## ------------------------------------------------

dist_exponential()$get_placeholders()
dist_mixture(list(dist_dirac(), dist_exponential()))$get_placeholders()

## ------------------------------------------------
## Method `Distribution$get_params`
## ------------------------------------------------

dist_mixture(list(dist_dirac(), dist_exponential()))$get_params(
  with_params = list(probs = list(0.5, 0.5))
)

## ------------------------------------------------
## Method `Distribution$get_param_bounds`
## ------------------------------------------------

dist_mixture(
  list(dist_dirac(), dist_exponential()),
  probs = list(0.5, 0.5)
)$get_param_bounds()

dist_mixture(
  list(dist_dirac(), dist_exponential())
)$get_param_bounds()

dist_genpareto()$get_param_bounds()
dist_genpareto1()$get_param_bounds()

## ------------------------------------------------
## Method `Distribution$get_param_constraints`
## ------------------------------------------------

dist_mixture(
  list(dist_dirac(), dist_exponential())
)$get_param_constraints()

## ------------------------------------------------
## Method `Distribution$export_functions`
## ------------------------------------------------

tmp_env <- new.env(parent = globalenv())
dist_exponential()$export_functions(
  name = "exp",
  envir = tmp_env,
  with_params = list(rate = 2.0)
)
evalq(
  fitdistrplus::fitdist(rexp(100), "exp"),
  envir = tmp_env
)

Fit a Blended mixture using an ECME-Algorithm

Description

Fit a Blended mixture using an ECME-Algorithm

Usage

fit_blended(
  dist,
  obs,
  start,
  min_iter = 0L,
  max_iter = 100L,
  skip_first_e = FALSE,
  tolerance = 1e-05,
  trace = FALSE,
  ...
)

Arguments

dist

A BlendedDistribution. It is assumed, that breaks and bandwidths are not a placeholder and that weights are to be estimated.
obs

Set of observations as produced by trunc_obs() or convertible via as_trunc_obs().
start

Initial values of all placeholder parameters. If missing, starting values are obtained from fit_dist_start().
min_iter

Minimum number of EM-Iterations
max_iter

Maximum number of EM-Iterations (weight updates)
skip_first_e

Skip the first E-Step (update Probability weights)? This can help if the initial values cause a mixture component to vanish in the first E-Step before the starting values can be improved.
tolerance

Numerical tolerance.
trace

Include tracing information in output? If TRUE, additional tracing information will be added to the result list.
...

Passed to fit_dist_start() if start is missing.

Value

A list with elements

  • params the fitted parameters in the same structure as init.

  • params_hist (if trace is TRUE) the history of parameters (after each e- and m- step)

  • iter the number of outer EM-iterations

  • logLik the final log-likelihood

See Also

Other distribution fitting functions: fit_dist(), fit_erlang_mixture(), fit_mixture()

Examples

dist <- dist_blended(
   list(
     dist_exponential(),
     dist_genpareto()
   )
 )

params <- list(
  probs = list(0.9, 0.1),
  dists = list(
    list(rate = 2.0),
    list(u = 1.5, xi = 0.2, sigmau = 1.0)
  ),
  breaks = list(1.5),
  bandwidths = list(0.3)
)

x <- dist$sample(100L, with_params = params)

dist$default_params$breaks <- params$breaks
dist$default_params$bandwidths <- params$bandwidths
if (interactive()) {
  fit_blended(dist, x)
}

Fit a general distribution to observations

Description

The default implementation performs maximum likelihood estimation on all placeholder parameters.

Usage

fit_dist(dist, obs, start, ...)

fit_dist_direct(dist, obs, start, ..., .start_with_default = FALSE)

## S3 method for class 'Distribution'
fit(object, obs, start, ...)

Arguments

dist

A Distribution object.
obs

Set of observations as produced by trunc_obs() or convertible via as_trunc_obs().
start

Initial values of all placeholder parameters. If missing, starting values are obtained from fit_dist_start().
...

Distribution-specific arguments for the fitting procedure
.start_with_default

Before directly optimising the likelihood, use an optimised algorithm for finding better starting values?
object

same as parameter dist

Details

For Erlang mixture distributions and for Mixture distributions, an EM-Algorithm is instead used to improve stability.

fit() and fit_dist() will chose an optimisation method optimized for the specific distribution given. fit_dist_direct() can be used to force direct maximisation of the likelihood.

Value

A list with at least the elements

  • params the fitted parameters in the same structure as init.

  • logLik the final log-likelihood

Additional information may be provided depending on dist.

See Also

Other distribution fitting functions: fit_blended(), fit_erlang_mixture(), fit_mixture()

Other distribution fitting functions: fit_blended(), fit_erlang_mixture(), fit_mixture()

Examples

x <- rexp(100)
lambda_hat <- 1 / mean(x)
lambda_hat2 <- fit_dist(dist_exponential(), x)$params$rate
identical(lambda_hat, lambda_hat2)
dist <- dist_mixture(list(dist_normal(), dist_translate(dist_exponential(), offset = 6)))
params <- list(
  dists = list(list(mean = 5, sd = 1), list(dist = list(rate = 1))), probs = list(0.95, 0.05)
)
set.seed(2000)
u <- runif(100, 10, 20)
x <- dist$sample(100, with_params = params)
obs <- trunc_obs(x = x[x <= u], tmin = -Inf, tmax = u[x <= u])

default_fit <- fit_dist(dist, obs)
direct_fit <- fit_dist_direct(dist, obs)
# NB: direct optimisation steps with pre-run take a few seconds

direct_fit_init <- fit_dist_direct(dist, obs, start = default_fit$params)
direct_fit_auto_init <- fit_dist_direct(dist, obs, .start_with_default = TRUE)

stopifnot(direct_fit_init$logLik == direct_fit_auto_init$logLik)

c(default_fit$logLik, direct_fit$logLik, direct_fit_init$logLik)

Find starting values for distribution parameters

Description

Find starting values for distribution parameters

Usage

## S3 method for class 'MixtureDistribution'
fit_dist_start(dist, obs, dists_start = NULL, ...)

fit_dist_start(dist, obs, ...)

Arguments

dist

A Distribution object.
obs

Observations to fit to.
dists_start

List of initial parameters for all component distributions. If left empty, initialisation will be automatically performed using fit_dist_start() with all observations in the support of each respective component.
...

Additional arguments for the initialisation procedure

Value

A list of initial parameters suitable for passing to fit_dist().

Examples

fit_dist_start(dist_exponential(), rexp(100))

Fit an Erlang mixture using an ECME-Algorithm

Description

Fit an Erlang mixture using an ECME-Algorithm

Usage

fit_erlang_mixture(
  dist,
  obs,
  start,
  min_iter = 0L,
  max_iter = 100L,
  skip_first_e = FALSE,
  tolerance = 1e-05,
  trace = FALSE,
  parallel = FALSE,
  ...
)

Arguments

dist

An ErlangMixtureDistribution. It is assumed, that both probs and scale are to be estimated.
obs

Set of observations as produced by trunc_obs() or convertible via as_trunc_obs().
start

Initial values of all placeholder parameters. If missing, starting values are obtained from fit_dist_start().
min_iter

Minimum number of EM-Iterations
max_iter

Maximum number of EM-Iterations (weight updates)
skip_first_e

Skip the first E-Step (update Probability weights)? This can help if the initial values cause a mixture component to vanish in the first E-Step before the starting values can be improved.
tolerance

Numerical tolerance.
trace

Include tracing information in output? If TRUE, additional tracing information will be added to the result list.
parallel

Enable experimental parallel evaluation of expected log-likelihood?
...

Passed to fit_dist_start() if start is missing.

Value

A list with elements

  • params the fitted parameters in the same structure as init.

  • params_hist (if trace is TRUE) the history of parameters (after each e- and m- step). Otherwise an empty list.

  • iter the number of outer EM-iterations

  • logLik the final log-likelihood

See Also

Other distribution fitting functions: fit_blended(), fit_dist(), fit_mixture()

Examples

dist <- dist_erlangmix(list(NULL, NULL, NULL))
params <- list(
  shapes = list(1L, 4L, 12L),
  scale = 2.0,
  probs = list(0.5, 0.3, 0.2)
)
x <- dist$sample(100L, with_params = params)
fit_erlang_mixture(dist, x, init = "kmeans")

Fit a generic mixture using an ECME-Algorithm

Description

Fit a generic mixture using an ECME-Algorithm

Usage

fit_mixture(
  dist,
  obs,
  start,
  min_iter = 0L,
  max_iter = 100L,
  skip_first_e = FALSE,
  tolerance = 1e-05,
  trace = FALSE,
  ...
)

Arguments

dist

A MixtureDistribution specifying the structure of the mixture. Free parameters are to be optimised. The dominating measure for likelihoods must be constant, so for example dist_dirac() may not have its point parameter free.
obs

Set of observations as produced by trunc_obs() or convertible via as_trunc_obs().
start

Initial values of all placeholder parameters. If missing, starting values are obtained from fit_dist_start().
min_iter

Minimum number of EM-Iterations
max_iter

Maximum number of EM-Iterations (weight updates)
skip_first_e

Skip the first E-Step (update Probability weights)? This can help if the initial values cause a mixture component to vanish in the first E-Step before the starting values can be improved.
tolerance

Numerical tolerance.
trace

Include tracing information in output? If TRUE, additional tracing information will be added to the result list.
...

Passed to fit_dist_start() if start is missing.

Value

A list with elements

  • params the fitted parameters in the same structure as init.

  • params_hist (if trace is TRUE) the history of parameters (after each e- and m- step)

  • iter the number of outer EM-iterations

  • logLik the final log-likelihood

See Also

Other distribution fitting functions: fit_blended(), fit_dist(), fit_erlang_mixture()

Examples

dist <- dist_mixture(
  list(
    dist_dirac(0.0),
    dist_exponential()
  )
)

params <- list(
  probs = list(0.1, 0.9),
  dists = list(
    list(),
    list(rate = 1.0)
  )
)

x <- dist$sample(100L, with_params = params)

fit_mixture(dist, x)

Fit a neural network based distribution model to data

Description

This function delegates most work to keras3::fit.keras.src.models.model.Model() and performs additional consistency checks to make sure tf_compile_model() was called with the appropriate options to support fitting the observations y as well as automatically converting y to a n x 6 matrix needed by the compiled loss function.

Usage

## S3 method for class 'reservr_keras_model'
fit(
  object,
  x,
  y,
  batch_size = NULL,
  epochs = 10,
  verbose = getOption("keras.fit_verbose", default = 1),
  callbacks = NULL,
  view_metrics = getOption("keras.view_metrics", default = "auto"),
  validation_split = 0,
  validation_data = NULL,
  shuffle = TRUE,
  class_weight = NULL,
  sample_weight = NULL,
  initial_epoch = 0,
  steps_per_epoch = NULL,
  validation_steps = NULL,
  ...
)

Arguments

object

A compiled reservr_keras_model as obtained by tf_compile_model().
x

A list of input tensors (predictors)
y

A trunc_obs tibble of observed outcomes, or something convertible via as_trunc_obs().
batch_size

Integer or NULL. Number of samples per gradient update. If unspecified, batch_size will default to 32. Do not specify the batch_size if your data is in the form of TF Datasets or generators, (since they generate batches).
epochs

Integer. Number of epochs to train the model. An epoch is an iteration over the entire x and y data provided (unless the steps_per_epoch flag is set to something other than NULL). Note that in conjunction with initial_epoch, epochs is to be understood as "final epoch". The model is not trained for a number of iterations given by epochs, but merely until the epoch of index epochs is reached.
verbose

"auto", 0, 1, or 2. Verbosity mode. 0 = silent, 1 = progress bar, 2 = one line per epoch. "auto" becomes 1 for most cases, 2 if in a knitr render or running on a distributed training server. Note that the progress bar is not particularly useful when logged to a file, so verbose=2 is recommended when not running interactively (e.g., in a production environment). Defaults to "auto".
callbacks

List of Callback() instances. List of callbacks to apply during training. See ⁠callback_*⁠.
view_metrics

View realtime plot of training metrics (by epoch). The default ("auto") will display the plot when running within RStudio, metrics were specified during model compile(), epochs > 1 and verbose > 0. Set the global options(keras.view_metrics = ) option to establish a different default.
validation_split

Float between 0 and 1. Fraction of the training data to be used as validation data. The model will set apart this fraction of the training data, will not train on it, and will evaluate the loss and any model metrics on this data at the end of each epoch. The validation data is selected from the last samples in the x and y data provided, before shuffling. This argument is not supported when x is a TF Dataset or generator. If both validation_data and validation_split are provided, validation_data will override validation_split.
validation_data

Data on which to evaluate the loss and any model metrics at the end of each epoch. The model will not be trained on this data. Thus, note the fact that the validation loss of data provided using validation_split or validation_data is not affected by regularization layers like noise and dropout. validation_data will override validation_split. It could be:

  • A tuple ⁠(x_val, y_val)⁠ of arrays or tensors.

  • A tuple ⁠(x_val, y_val, val_sample_weights)⁠ of arrays.

  • A generator returning ⁠(inputs, targets)⁠ or ⁠(inputs, targets, sample_weights)⁠.

shuffle

Boolean, whether to shuffle the training data before each epoch. This argument is ignored when x is a generator or a TF Dataset.
class_weight

Optional named list mapping class indices (integers, 0-based) to a weight (float) value, used for weighting the loss function (during training only). This can be useful to tell the model to "pay more attention" to samples from an under-represented class. When class_weight is specified and targets have a rank of 2 or greater, either y must be one-hot encoded, or an explicit final dimension of 1 must be included for sparse class labels.
sample_weight

Optional array of weights for the training samples, used for weighting the loss function (during training only). You can either pass a flat (1D) array/vector with the same length as the input samples (1:1 mapping between weights and samples), or in the case of temporal data, you can pass a 2D array (matrix) with shape ⁠(samples, sequence_length)⁠, to apply a different weight to every timestep of every sample. This argument is not supported when x is a TF Dataset or generator, instead provide the sample_weights as the third element of x. Note that sample weighting does not apply to metrics specified via the metrics argument in compile(). To apply sample weighting to your metrics, you can specify them via the weighted_metrics in compile() instead.
initial_epoch

Integer. Epoch at which to start training (useful for resuming a previous training run).
steps_per_epoch

Integer or NULL. Total number of steps (batches of samples) before declaring one epoch finished and starting the next epoch. When training with input tensors such as backend-native tensors, the default NULL is equal to the number of samples in your dataset divided by the batch size, or 1 if that cannot be determined. If x is a TF Dataset, and steps_per_epoch is NULL, the epoch will run until the input dataset is exhausted. When passing an infinitely repeating dataset, you must specify the steps_per_epoch argument. If steps_per_epoch = -1 the training will run indefinitely with an infinitely repeating dataset.
validation_steps

Only relevant if validation_data is provided. Total number of steps (batches of samples) to draw before stopping when performing validation at the end of every epoch. If validation_steps is NULL, validation will run until the validation_data dataset is exhausted. In the case of an infinitely repeated dataset, it will run into an infinite loop. If validation_steps is specified and only part of the dataset will be consumed, the evaluation will start from the beginning of the dataset at each epoch. This ensures that the same validation samples are used every time.
...

Unused. If old arguments are supplied, an error message will be raised informing how to fix the issue.

Details

Additionally, the default batch_size is min(nrow(y), 10000) instead of keras default of 32 because the latter is a very bad choice for fitting most distributions since the involved loss is much less stable than typical losses used in machine learning, leading to divergence for small batch sizes.

Value

A history object that contains all information collected during training. The model object will be updated in-place as a side-effect.

See Also

predict.reservr_keras_model tf_compile_model keras3::fit.keras.src.models.model.Model

Examples

dist <- dist_exponential()
params <- list(rate = 1.0)
N <- 100L
rand_input <- runif(N)
x <- dist$sample(N, with_params = params)

if (interactive()) {
  tf_in <- keras3::layer_input(1L)
  mod <- tf_compile_model(
    inputs = list(tf_in),
    intermediate_output = tf_in,
    dist = dist,
    optimizer = keras3::optimizer_adam(),
    censoring = FALSE,
    truncation = FALSE
  )

  tf_fit <- fit(
    object = mod,
    x = k_matrix(rand_input),
    y = x,
    epochs = 10L,
    callbacks = list(
      callback_debug_dist_gradients(mod, k_matrix(rand_input), x, keep_grads = TRUE)
    )
  )
}

Flatten / Inflate parameter lists / vectors

Description

Flatten / Inflate parameter lists / vectors

Usage

flatten_params(params)

flatten_params_matrix(params)

flatten_bounds(bounds)

inflate_params(flat_params)

Arguments

params

A named list of parameters to be flattened. Should be in a form to be passed as the with_params argument to most distribution functions.
bounds

List of parameter bounds as returned by dist$get_param_bounds()
flat_params

A named numeric vector of parameters

Value

flatten_params returns a 'flattened' vector of parameters. It is intended as an adapter for multi-dimensional optimisation functions to distribution objects.

flatten_params_matrix returns a 'flattened' matrix of parameters. It is intended as an adapter for multi-dimensional optimisation functions to distribution objects. Each column corresponds to one input element.

flatten_bounds returns a named list of vectors with names lower and upper. Containing the upper and lower bounds of each parameter.

inflate_params returns an 'inflated' list of parameters. This can be passed as the with_params argument to most distribution functions.

Examples

library(ggplot2)

mm <- dist_mixture(list(
  dist_exponential(NULL),
  dist_lognormal(0.5, NULL)
), list(NULL, 1))

ph <- mm$get_placeholders()
ph_flat <- flatten_params(ph)
ph_reinflated <- inflate_params(ph_flat)
ph_flat[] <- c(1, 1, 6)
ph_sample <- inflate_params(ph_flat)

x <- mm$sample(
  100,
  with_params = ph_sample
)

emp_cdf <- ecdf(x)

ggplot(data.frame(t = seq(from = min(x), to = max(x), length.out = 100))) %+%
  geom_point(aes(x = t, y = emp_cdf(t))) %+%
  geom_line(aes(x = t, y = mm$probability(t, with_params = ph_sample)),
            linetype = 2)

The Generalized Pareto Distribution (GPD)

Description

These functions provide information about the generalized Pareto distribution with threshold u. dgpd gives the density, pgpd gives the distribution function, qgpd gives the quantile function and rgpd generates random deviates.

Usage

rgpd(n = 1L, u = 0, sigmau = 1, xi = 0)

dgpd(x, u = 0, sigmau = 1, xi = 0, log = FALSE)

pgpd(q, u = 0, sigmau = 1, xi = 0, lower.tail = TRUE, log.p = FALSE)

qgpd(p, u = 0, sigmau = 1, xi = 0, lower.tail = TRUE, log.p = FALSE)

Arguments

n

integer number of observations.
u

threshold parameter (minimum value).
sigmau

scale parameter (must be positive).
xi

shape parameter
x, q

vector of quantiles.
log, log.p

logical; if TRUE, probabilities/densities p are given as log(p).
lower.tail

logical; if TRUE (default), probabilities are P(X≤x)P(X \le x), otherwise P(X>x)P(X > x).
p

vector of probabilities.

Details

If u, sigmau or xi are not specified, they assume the default values of 0, 1 and 0 respectively.

The generalized Pareto distribution has density

f(x)=1/σu(1+ξz)(−1/ξ−1)f(x) = 1 / \sigma_u (1 + \xi z)^(- 1 / \xi - 1)

where z=(x−u)/σuz = (x - u) / \sigma_u and f(x)=exp(−z)f(x) = exp(-z) if ξ\xi is 0. The support is x≥ux \ge u for ξ≥0\xi \ge 0 and u≤x≤u−σu/ξu \le x \le u - \sigma_u / \xi for ξ<0\xi < 0.

The Expected value exists if ξ<1\xi < 1 and is equal to

E(X)=u+σu/(1−ξ)E(X) = u + \sigma_u / (1 - \xi)

k-th moments exist in general for kξ<1k\xi < 1.

Value

rgpd generates random deviates.

dgpd gives the density.

pgpd gives the distribution function.

qgpd gives the quantile function.

References

https://en.wikipedia.org/wiki/Generalized_Pareto_distribution

Examples

x <- rgpd(1000, u = 1, sigmau = 0.5, xi = 0.1)
xx <- seq(-1, 10, 0.01)
hist(x, breaks = 100, freq = FALSE, xlim = c(-1, 10))
lines(xx, dgpd(xx, u = 1, sigmau = 0.5, xi = 0.1))

plot(xx, dgpd(xx, u = 1, sigmau = 1, xi = 0), type = "l")
lines(xx, dgpd(xx, u = 0.5, sigmau = 1, xi = -0.3), col = "blue", lwd = 2)
lines(xx, dgpd(xx, u = 1.5, sigmau = 1, xi = 0.3), col = "red", lwd = 2)

plot(xx, dgpd(xx, u = 1, sigmau = 1, xi = 0), type = "l")
lines(xx, dgpd(xx, u = 1, sigmau = 0.5, xi = 0), col = "blue", lwd = 2)
lines(xx, dgpd(xx, u = 1, sigmau = 2, xi = 0), col = "red", lwd = 2)

Adaptive Gauss-Kronrod Quadrature for multiple limits

Description

Integrates fun over the bounds [ lower, upper ] vectorized over lower and upper. Vectorized list structures of parameters can also be passed.

Usage

integrate_gk(
  fun,
  lower,
  upper,
  params = list(),
  .tolerance = .Machine$double.eps^0.25,
  .max_iter = 100L
)

Arguments

fun

A function to integrate. Must be vectorized and take one or two arguments, the first being points to evaluate at and the second (optionally) being parameters to apply. It must return a numeric vector the same length as its first input.

Currently, infinite bounds are not supported.
lower, upper

Integration bounds. Must have the same length.
params

Parameters to pass as a second argument to fun. The actual parameters must have the same length as the number of integrals to compute. Can be a possibly nested list structures containing numeric vectors. Alternatively, can be a matrix with the same number of rows as the number of integrals to compute.
.tolerance

Absolute element-wise tolerance.
.max_iter

Maximum number of iterations. The number of integration intervals will be at most length(lower) * .max_iter. Therefor the maximum number of function evaluations per integration interval will be 15 * .max_iter.

Details

The integration error is estimated by the Gauss-Kronrod quadrature as the absolute difference between the 7-point quadrature and the 15-point quadrature. Integrals that did not converge will be bisected at the midpoint. The params object will be recursively subsetted on all numeric vectors with the same length as the number of observations.

Value

A vector of integrals with the i-th entry containing an approximation of the integral of fun(t, pick_params_at(params, i)) dt over the interval lower[i] to upper[i]

Examples

# Argument recycling and parallel integration of two intervals
integrate_gk(sin, 0, c(pi, 2 * pi))

dist <- dist_exponential()
integrate_gk(
  function(x, p) dist$density(x, with_params = p),
  lower = 0, upper = 1:10,
  params = list(rate = 1 / 1:10)
)
dist$probability(1:10, with_params = list(rate = 1 / 1:10))

Intervals

Description

Intervals

Usage

interval(
  range = c(-Inf, Inf),
  ...,
  include_lowest = closed,
  include_highest = closed,
  closed = FALSE,
  integer = FALSE,
  read_only = FALSE
)

is.Interval(x)

Arguments

range

The interval boundaries as a sorted two-element numeric vector.
...

First argument is used as the endpoint if range has length 1. Additional arguments, or any if range has length 2, cause a warning and will be ignored.
include_lowest

Is the lower boundary part of the interval?
include_highest

Is the upper boundary part of the interval?
closed

Is the interval closed?
integer

Is the interval only over the integers?
read_only

Make the interval object read-only?
x

An object.

Value

interval returns an Interval. is.Interval returns TRUE if x is an Interval, FALSE otherwise.

See Also

interval-operations

Examples

# The real line
interval()

# Closed unit interval
interval(c(0, 1), closed = TRUE)
# Alternative form
interval(0, 1, closed = TRUE)

# Non-negative real line
interval(c(0, Inf), include_lowest = TRUE)

Convex union and intersection of intervals

Description

Convex union and intersection of intervals

Usage

interval_union(..., intervals = list())

interval_intersection(..., intervals = list())

Arguments

...

appened to intervals if present.
intervals

A list of Intervals.

Value

interval_union returns the convex union of all intervals in intervals. This is the smallest interval completely containing all intervals.

interval_intersection returns the set intersection of all intervals in intervals. The empty set is represented by the open interval (0, 0).

See Also

interval

Examples

interval_union(
  interval(c(0, 1), closed = TRUE),
  interval(c(1, 2))
)

interval_union(
  interval(c(0, 5)),
  interval(c(1, 4), closed = TRUE)
)

# Convex union is not equal to set union:
interval_union(
  interval(c(0, 1)),
  interval(c(2, 3))
)

# The empty union is {}
interval_union()

interval_intersection(
  interval(c(0, 1)),
  interval(c(0.5, 2))
)

interval_intersection(
  interval(c(0, Inf)),
  interval(c(-Inf, 0))
)

interval_intersection(
  interval(c(0, Inf), include_lowest = TRUE),
  interval(c(-Inf, 0), include_highest = TRUE)
)

interval_intersection(
  interval(c(0, 5)),
  interval(c(1, 6), closed = TRUE)
)

# The empty intersection is (-Inf, Inf)
interval_intersection()

Test if object is a Distribution

Description

Test if object is a Distribution

Usage

is.Distribution(object)

Arguments

object

An R object.

Value

TRUE if object is a Distribution, FALSE otherwise.

Examples

is.Distribution(dist_dirac())

Cast to a TensorFlow matrix

Description

Cast to a TensorFlow matrix

Usage

k_matrix(x, dtype = NULL)

Arguments

x

Numeric object to be converted to a matrix Tensor.
dtype

Type of the elements of the resulting tensor. Defaults to keras3::config_floatx().

Value

A two-dimensional tf.Tensor with values from x. The shape will be ⁠(nrow(x), ncol(x))⁠ where x is first converted to an R matrix via as.matrix().

Examples

if (interactive()) {
  k_matrix(diag(1:3))
  k_matrix(diag(1:3), dtype = "int32")
  # Vectors are converted to columns:
  k_matrix(1:3)
}

The Pareto Distribution

Description

These functions provide information about the Pareto distribution. dpareto gives the density, ppareto gives the distribution function, qpareto gives the quantile function and rpareto generates random deviates.

Usage

rpareto(n = 1L, shape = 0, scale = 1)

dpareto(x, shape = 1, scale = 1, log = FALSE)

ppareto(q, shape = 1, scale = 1, lower.tail = TRUE, log.p = FALSE)

qpareto(p, shape = 1, scale = 1, lower.tail = TRUE, log.p = FALSE)

Arguments

n

integer number of observations.
shape

shape parameter (must be positive).
scale

scale parameter (must be positive).
x, q

vector of quantiles.
log, log.p

logical; if TRUE, probabilities/densities p are given as log(p).
lower.tail

logical; if TRUE (default), probabilities are P(X≤x)P(X \le x), otherwise P(X>x)P(X > x).
p

vector of probabilities.

Details

If shape or scale are not specified, they assume the default values of 1.

The Pareto distribution with scale θ\theta and shape ξ\xi has density

f(x)=ξθξ/(x+θ)(ξ+1)f(x) = \xi \theta^\xi / (x + \theta)^(\xi + 1)

The support is x≥0x \ge 0.

The Expected value exists if ξ>1\xi > 1 and is equal to

E(X)=θ/(ξ−1)E(X) = \theta / (\xi - 1)

k-th moments exist in general for k<ξk < \xi.

Value

rpareto generates random deviates.

dpareto gives the density.

ppareto gives the distribution function.

qpareto gives the quantile function.

References

https://en.wikipedia.org/wiki/Pareto_distribution - named Lomax therein.

Examples

x <- rpareto(1000, shape = 10, scale = 5)
xx <- seq(-1, 10, 0.01)
hist(x, breaks = 100, freq = FALSE, xlim = c(-1, 10))
lines(xx, dpareto(xx, shape = 10, scale = 5))

plot(xx, dpareto(xx, shape = 10, scale = 5), type = "l")
lines(xx, dpareto(xx, shape = 3, scale = 5), col = "red", lwd = 2)

plot(xx, dpareto(xx, shape = 10, scale = 10), type = "l")
lines(xx, dpareto(xx, shape = 10, scale = 5), col = "blue", lwd = 2)
lines(xx, dpareto(xx, shape = 10, scale = 20), col = "red", lwd = 2)

Plot several distributions

Description

Plot several distributions

Usage

plot_distributions(
  ...,
  distributions = list(),
  .x,
  plots = c("density", "probability", "hazard"),
  with_params = list(),
  as_list = FALSE
)

Arguments

...

distribution objects (must be named)
distributions

Named list of distribution objects. This is concatenated with ....
.x

Numeric vector of points to evaluate at.
plots

Plots to be created. May be abbreviated. The plots will be stacked in the order given from top to bottom.
with_params

list of distribution parameters to be given to each distribution using with_params. If named, the names are matched to the distribution names. Otherwise, they are allocated positionally, index 1 corresponding to the first element of distributions, then all other elements from distributions followed by the arguments in ... in order.
as_list

return a list of ggplots instead of a patchwork?

Value

A stacked patchwork of the requested ggplots

Examples

rate <- 1
x <- rexp(20, rate)
d_emp <- dist_empirical(x, positive = TRUE)
d_exp <- dist_exponential()
plot_distributions(
  empirical = d_emp,
  theoretical = d_exp,
  estimated = d_exp,
  with_params = list(
    theoretical = list(rate = rate),
    estimated = list(rate = 1 / mean(x))
  ),
  .x = seq(1e-4, 5, length.out = 100)
)

Predict individual distribution parameters

Description

Predict individual distribution parameters

Usage

## S3 method for class 'reservr_keras_model'
predict(object, data, as_matrix = FALSE, ...)

Arguments

object

A compiled and trained reservr_keras_model.
data

Input data compatible with the model.
as_matrix

Return a parameter matrix instead of a list structure?
...

ignored

Value

A parameter list suitable for the with_params argument of the distribution family used for the model. Contains one set of parameters per row in data.

Examples

if (interactive()) {
  dist <- dist_exponential()
  params <- list(rate = 1.0)
  N <- 100L
  rand_input <- runif(N)
  x <- dist$sample(N, with_params = params)

  tf_in <- keras3::layer_input(1L)
  mod <- tf_compile_model(
    inputs = list(tf_in),
    intermediate_output = tf_in,
    dist = dist,
    optimizer = keras3::optimizer_adam(),
    censoring = FALSE,
    truncation = FALSE
  )

  tf_fit <- fit(
    object = mod,
    x = k_matrix(rand_input),
    y = x,
    epochs = 10L,
    callbacks = list(
      callback_debug_dist_gradients(mod, k_matrix(rand_input), x)
    )
  )

  tf_preds <- predict(mod, data = k_matrix(rand_input))
}

Determine probability of reporting under a Poisson arrival Process

Description

Determines the probability that claims occuring under a Poisson process with arrival intensity expo and reporting delay distribution dist during the time between t_min and t_max are reported between tau_min and tau_max.

Usage

prob_report(
  dist,
  intervals,
  expo = NULL,
  with_params = list(),
  .tolerance = .Machine$double.eps^0.5,
  .max_iter = 100L,
  .try_compile = TRUE
)

Arguments

dist

A reporting delay Distribution, or a compiled interval probability function.
intervals

A data frame with columns xmin, xmax, tmin, tmax. Claims occur within ⁠[xmin, xmax]⁠ and be reported within ⁠[tmin, tmax]⁠.
expo

Poisson intensity. If given, must be a vectorised function that yields the intensity of the claim arrival process at a specified time. expo = NULL is equivalent to a constant intensity function. expo is only relevant up to a multiplicative constant.
with_params

Parameters of dist to use. Can be a parameter set with different values for each interval. If dist is a compiled interval probability function, with_params can be a matrix instead.
.tolerance

Absolute element-wise tolerance.
.max_iter

Maximum number of iterations. The number of integration intervals will be at most length(lower) * .max_iter. Therefor the maximum number of function evaluations per integration interval will be 15 * .max_iter.
.try_compile

Try compiling the distributions probability function to speed up integration?

Details

The reporting probability is given by

P(x + d in [tmin, tmax] | x in [xmin, xmax]) = E(P(x + d in [tmin, tmax] | x) | x in [xmin, xmax]) / P(x in [xmin, xmax]) = int_[xmin, xmax] expo(x) P(x + d in [tmin, tmax]) dx = int_[xmin, xmax] expo(x) P(d in [tmin - x, tmax - x]) dx / int_[xmin, xmax] expo(x) dx

prob_report uses integrate_gk() to compute the two integrals.

Value

A vector of reporting probabilities, with one entry per row of intervals.

Examples

dist <- dist_exponential()
ints <- data.frame(
  xmin = 0,
  xmax = 1,
  tmin = seq_len(10) - 1.0,
  tmax = seq_len(10)
)
params <- list(rate = rep(c(1, 0.5), each = 5))

prob_report(dist, ints, with_params = params)

Quantiles of Distributions

Description

Produces quantiles corresponding to the given probabilities with configurable distribution parameters.

Usage

## S3 method for class 'Distribution'
quantile(x, probs = seq(0, 1, 0.25), with_params = list(), ..., .start = 0)

Arguments

x

A Distribution.
probs

Quantiles to compute.
with_params

Optional list of distribution parameters. Note that if x$has_capability("quantile") is false, with_params is assumed to contain only one set of parameters.
...

ignored
.start

Starting value if quantiles are computed numerically. Must be within the support of x.

Details

If x$has_capability("quantile") is true, this returns the same as x$quantile(probs, with_params = with_params). In this case, with_params may contain separate sets of parameters for each quantile to be determined.

Otherwise, a numerical estimation of the quantiles is done using the density and probability function. This method assumes with_params to cantain only one set of parameters. The strategy uses two steps:

  1. Find the smallest and largest quantiles in probs using a newton method starting from .start.

  2. Find the remaining quantiles with bisection using stats::uniroot().

Value

The quantiles of x corresponding to probs with parameters with_params.

Examples

# With quantiles available
dist <- dist_normal(sd = 1)
qqs <- quantile(dist, probs = rep(0.5, 3), with_params = list(mean = 1:3))
stopifnot(all.equal(qqs, 1:3))

# Without quantiles available
dist <- dist_erlangmix(shapes = list(1, 2, 3), scale = 1.0)
my_probs <- c(0, 0.01, 0.25, 0.5, 0.75, 1)
qqs <- quantile(
  dist, probs = my_probs,
  with_params = list(probs = list(0.5, 0.3, 0.2)), .start = 2
)

all.equal(dist$probability(qqs, with_params = list(probs = list(0.5, 0.3, 0.2))), my_probs)
# Careful: Numerical estimation of extreme quantiles can result in out-of-bounds values.
# The correct 0-quantile would be 0 in this case, but it was estimated < 0.
qqs[1L]

Soft-Max function

Description

Softmax for a vector x is defined as

Usage

softmax(x)

dsoftmax(x)

Arguments

x

A numeric vector or matrix

Details

si=exp⁡(xi)/∑kexp⁡(xk)s_i = \exp(x_i) / \sum_k \exp(x_k)

It satisfies sum(s) == 1.0 and can be used to smoothly enforce a sum constraint.

Value

softmax returns the softmax of x; rowwise if x is a matrix.

dsoftmax returns the Jacobi-matrix of softmax(x) at x. x must be a vector.

Examples

softmax(c(5, 5))
softmax(diag(nrow = 5, ncol = 6))

Compile a Keras model for truncated data under dist

Description

Compile a Keras model for truncated data under dist

Usage

tf_compile_model(
  inputs,
  intermediate_output,
  dist,
  optimizer,
  censoring = TRUE,
  truncation = TRUE,
  metrics = NULL,
  weighted_metrics = NULL
)

Arguments

inputs

List of keras input layers
intermediate_output

Intermediate model layer to be used as input to distribution parameters
dist

A Distribution to use for compiling the loss and parameter outputs
optimizer

String (name of optimizer) or optimizer instance. See ⁠optimizer_*⁠ family.
censoring

A flag, whether the compiled model should support censored observations. Set to FALSE for higher efficiency. fit(...) will error if the resulting model is used to fit censored observations.
truncation

A flag, whether the compiled model should support truncated observations. Set to FALSE for higher efficiency. fit(...) will warn if the resuting model is used to fit truncated observations.
metrics

List of metrics to be evaluated by the model during training and testing. Each of these can be:

  • a string (name of a built-in function),

  • a function, optionally with a "name" attribute or

  • a Metric() instance. See the ⁠metric_*⁠ family of functions.

Typically you will use metrics = c('accuracy'). A function is any callable with the signature result = fn(y_true, y_pred). To specify different metrics for different outputs of a multi-output model, you could also pass a named list, such as metrics = list(a = 'accuracy', b = c('accuracy', 'mse')). You can also pass a list to specify a metric or a list of metrics for each output, such as metrics = list(c('accuracy'), c('accuracy', 'mse')) or metrics = list('accuracy', c('accuracy', 'mse')). When you pass the strings 'accuracy' or 'acc', we convert this to one of metric_binary_accuracy(), metric_categorical_accuracy(), metric_sparse_categorical_accuracy() based on the shapes of the targets and of the model output. A similar conversion is done for the strings "crossentropy" and "ce" as well. The metrics passed here are evaluated without sample weighting; if you would like sample weighting to apply, you can specify your metrics via the weighted_metrics argument instead.

If providing an anonymous R function, you can customize the printed name during training by assigning ⁠attr(<fn>, "name") <- "my_custom_metric_name"⁠, or by calling custom_metric("my_custom_metric_name", <fn>)
weighted_metrics

List of metrics to be evaluated and weighted by sample_weight or class_weight during training and testing.

Value

A reservr_keras_model that can be used to train truncated and censored observations from dist based on input data from inputs.

Examples

dist <- dist_exponential()
params <- list(rate = 1.0)
N <- 100L
rand_input <- runif(N)
x <- dist$sample(N, with_params = params)

if (interactive()) {
  tf_in <- keras3::layer_input(1L)
  mod <- tf_compile_model(
    inputs = list(tf_in),
    intermediate_output = tf_in,
    dist = dist,
    optimizer = keras3::optimizer_adam(),
    censoring = FALSE,
    truncation = FALSE
  )
}

Initialise model weights to a global parameter fit

Description

Initialises a compiled reservr_keras_model weights such that the predictions are equal to, or close to, the distribution parameters given by params.

Usage

tf_initialise_model(
  model,
  params,
  mode = c("scale", "perturb", "zero", "none")
)

Arguments

model

A reservr_compiled_model obtained by tf_compile_model().
params

A list of distribution parameters compatible with model.
mode

An initialisation mode

scale

Initialise the biases according to params and the kernels uniform on [-0.1, 0.1] * bias scale.

perturb

Initialise the biases according to params and leave the kernels as is.

zero

Initialise the biases according to params and set the kernel to zero.

none

Don't modify the weights.

Value

Invisibly model with changed weights

Examples

dist <- dist_exponential()
group <- sample(c(0, 1), size = 100, replace = TRUE)
x <- dist$sample(100, with_params = list(rate = group + 1))
global_fit <- fit(dist, x)

if (interactive()) {
  library(keras3)
  l_in <- layer_input(shape = 1L)
  mod <- tf_compile_model(
    inputs = list(l_in),
    intermediate_output = l_in,
    dist = dist,
    optimizer = optimizer_adam(),
    censoring = FALSE,
    truncation = FALSE
  )
  tf_initialise_model(mod, global_fit$params)
  fit_history <- fit(
    mod,
    x = group,
    y = x,
    epochs = 200L
  )

  predicted_means <- predict(mod, data = as_tensor(c(0, 1), config_floatx()))
}

Define a set of truncated observations

Description

If x is missing, both xmin and xmax must be specified.

Usage

trunc_obs(x, xmin = x, xmax = x, tmin = -Inf, tmax = Inf, w = 1)

as_trunc_obs(.data)

truncate_obs(.data, tmin_new = -Inf, tmax_new = Inf, .partial = FALSE)

repdel_obs(.data, accident, delay, time, .truncate = FALSE)

Arguments

x

Observations
xmin, xmax

Censoring bounds. If xmin != xmax, x must be NA.
tmin, tmax

Truncation bounds. May vary per observation.
w

Case weights
.data

A data frame or numeric vector.
tmin_new

New truncation minimum
tmax_new

New truncation maximum
.partial

Enable partial truncation of censored observations? This could potentially create inconsistent data if the actual observation lies outside of the truncation bounds but the censoring interval overlaps.
accident

accident time (unquoted, evaluated in .data)
delay

reporting delay (unquoted, evaluated in .data)
time

evaluation time (unquoted, evaluated in .data)
.truncate

Should claims reported after time be silently discarded? If there are claims reported after time and .truncate is FALSE, an error will be raised.

Details

Uncensored observations must satisfy tmin <= xmin = x = xmax <= tmax. Censored observations must satisfy ⁠tmin <= xmin < xmax <= tmax⁠ and x = NA.

Value

trunc_obs: A trunc_obs tibble with columns x, xmin, xmax, tmin and tmax describing possibly interval-censored observations with truncation

as_trunc_obs returns a trunc_obs tibble.

truncate_obs returns a trunc_obs tibble with possibly fewer observations than .data and updated truncation bounds.

repdel_obs returns a trunc_obs tibble corresponding to the reporting delay observations of each claim. If .truncate is FALSE, the result is guaranteed to have the same number of rows as .data.

Examples

N <- 100
x <- rexp(N, 0.5)

# Random, observation dependent truncation intervals
tmin <- runif(N, 0, 1)
tmax <- tmin + runif(N, 1, 2)

oob <- x < tmin | x > tmax
x <- x[!oob]
tmin <- tmin[!oob]
tmax <- tmax[!oob]

# Number of observations after truncation
N <- length(x)

# Randomly interval censor 30% of observations
cens <- rbinom(N, 1, 0.3) == 1L
xmin <- x
xmax <- x
xmin[cens] <- pmax(tmin[cens], floor(x[cens]))
xmax[cens] <- pmin(tmax[cens], ceiling(x[cens]))
x[cens] <- NA

trunc_obs(x, xmin, xmax, tmin, tmax)

as_trunc_obs(c(1, 2, 3))
as_trunc_obs(data.frame(x = 1:3, tmin = 0, tmax = 10))
as_trunc_obs(data.frame(x = c(1, NA), xmin = c(1, 2), xmax = c(1, 3)))
truncate_obs(1:10, tmin_new = 2.0, tmax_new = 8.0)

Truncate claims data subject to reporting delay

Description

Truncate claims data subject to reporting delay

Usage

truncate_claims(data, accident, delay, time, .report_col = "report")

Arguments

data

Full claims data including IBNR
accident

Accident times. May be an unquoted column name from data.
delay

Reporting delays. May be an unquoted column name from data.
time

Observation time (scalar number or one per claim). Claims with accident + delay > time will be truncated. Set time = Inf to only compute reporting times and perform no truncation.
.report_col

NULL or a column name to store the reporting time report = accident + delay.

Value

Truncated data. The reporting time is stored in a colnumn named by .report_col unless .report_col is NULL. If both .report_col is NULL and time contains only Infs, a warning will be issued since data will be returned unchanged and no work will be done.

Examples

claims_full <- data.frame(
  acc = runif(100),
  repdel = rexp(100)
)
tau <- 2.0
truncate_claims(claims_full, acc, repdel, tau)

Compute weighted moments

Description

Compute weighted moments

Usage

weighted_moments(x, w, n = 2L, center = TRUE)

Arguments

x

Observations
w

Case weights (optional)
n

Number of moments to calculate
center

Calculate centralized moments (default) or noncentralized moments, i.e. E((X - E(X))^k) or E(X^k).

Value

A vector of length n where the kth entry is the kth weighted moment of x with weights w. If center is TRUE the moments are centralized, i.e. E((X - E(X))^k). The first moment is never centralized. The moments are scaled with 1 / sum(w), so they are not de-biased.

e.g. the second central weighted moment weighted_moment(x, w)[2L] is equal to var(rep(x, w)) * (sum(w) - 1) / sum(w) for integer w

See Also

Other weighted statistics: weighted_quantile(), weighted_tabulate()

Examples

weighted_moments(rexp(100))
weighted_moments(c(1, 2, 3), c(1, 2, 3))
c(mean(rep(1:3, 1:3)), var(rep(1:3, 1:3)) * 5 / 6)

Compute weighted quantiles

Description

Compute weighted quantiles

Usage

weighted_quantile(x, w, probs)

weighted_median(x, w)

Arguments

x

Observations
w

Case weights (optional)
probs

Quantiles to calculate

Value

A vector the same length as probs with the corresponding weighted quantiles of x with weight w. For integer weights, this is equivalent to quantile(rep(x, w), probs)

The weighted median of x with weights w. For integer weights, this is equivalent to median(rep(x, w))

See Also

Other weighted statistics: weighted_moments(), weighted_tabulate()

Examples

weighted_median(1:6)
weighted_median(1:3, c(1, 4, 9))
weighted_median(1:3, c(9, 4, 1))

weighted_quantile(1:3, c(1, 4, 9), seq(0.0, 1.0, by = 0.25))
quantile(rep(1:3, c(1, 4, 9)), seq(0.0, 1.0, by = 0.25))

Compute weighted tabulations

Description

Computes the sum of w grouped by bin. If w is missing the result is equivalent to tabulate(bin, nbins)

Usage

weighted_tabulate(bin, w, nbins = max(1L, bin, na.rm = TRUE))

Arguments

bin

An integer vector with values from 1L to nbins
w

Weights per entry in bin.
nbins

Number of bins

Value

A vector with length nbins where the ith result is equal to sum(w[bin == i]) or sum(bin == i) if w is missing. For integer weights, this is equivalent to tabulate(rep(bin, w), nbins).

See Also

Other weighted statistics: weighted_moments(), weighted_quantile()

Examples

weighted_tabulate(c(1, 1, 2))
weighted_tabulate(c(1, 1, 2), nbins = 3L)
weighted_tabulate(c(1, 1, 2), w = c(0.5, 0.5, 1), nbins = 3L)