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gpboost (version 0.7.9)

GPModel: Create a GPModel object

Description

Create a GPModel which contains a Gaussian process and / or mixed effects model with grouped random effects

Usage

GPModel(group_data = NULL, group_rand_coef_data = NULL,
  ind_effect_group_rand_coef = NULL,
  drop_intercept_group_rand_effect = NULL, gp_coords = NULL,
  gp_rand_coef_data = NULL, cov_function = "exponential",
  cov_fct_shape = 0, cov_fct_taper_range = 1, vecchia_approx = FALSE,
  num_neighbors = 30L, vecchia_ordering = "none",
  vecchia_pred_type = "order_obs_first_cond_obs_only",
  num_neighbors_pred = num_neighbors, cluster_ids = NULL,
  free_raw_data = FALSE, likelihood = "gaussian")

Value

A GPModel containing ontains a Gaussian process and / or mixed effects model with grouped random effects

Arguments

group_data

A vector or matrix whose columns are categorical grouping variables. The elements being group levels defining grouped random effects. The elements of 'group_data' can be integer, double, or character. The number of columns corresponds to the number of grouped (intercept) random effects

group_rand_coef_data

A vector or matrix with numeric covariate data for grouped random coefficients

ind_effect_group_rand_coef

A vector with integer indices that indicate the corresponding categorical grouping variable (=columns) in 'group_data' for every covariate in 'group_rand_coef_data'. Counting starts at 1. The length of this index vector must equal the number of covariates in 'group_rand_coef_data'. For instance, c(1,1,2) means that the first two covariates (=first two columns) in 'group_rand_coef_data' have random coefficients corresponding to the first categorical grouping variable (=first column) in 'group_data', and the third covariate (=third column) in 'group_rand_coef_data' has a random coefficient corresponding to the second grouping variable (=second column) in 'group_data'

drop_intercept_group_rand_effect

A vector of type logical (boolean). Indicates whether intercept random effects are dropped (only for random coefficients). If drop_intercept_group_rand_effect[k] is TRUE, the intercept random effect number k is dropped / not included. Only random effects with random slopes can be dropped.

gp_coords

A matrix with numeric coordinates (= inputs / features) for defining Gaussian processes

gp_rand_coef_data

A vector or matrix with numeric covariate data for Gaussian process random coefficients

cov_function

A string specifying the covariance function for the Gaussian process. The following covariance functions are available: "exponential", "gaussian", "matern", "powered_exponential", "wendland", and "exponential_tapered". For "exponential", "gaussian", and "powered_exponential", we follow the notation and parametrization of Diggle and Ribeiro (2007). For "matern", we follow the notation of Rassmusen and Williams (2006). For "wendland", we follow the notation of Bevilacqua et al. (2019). A covariance function with the suffix "_tapered" refers to a covariance function that is multiplied by a compactly supported Wendland covariance function (= tapering)

cov_fct_shape

A numeric specifying the shape parameter of the covariance function (=smoothness parameter for Matern and Wendland covariance). For the Wendland covariance function, we follow the notation of Bevilacqua et al. (2019)). This parameter is irrelevant for some covariance functions such as the exponential or Gaussian

cov_fct_taper_range

A numeric specifying the range parameter of the Wendland covariance function / taper. We follow the notation of Bevilacqua et al. (2019)

vecchia_approx

A boolean. If TRUE, the Vecchia approximation is used

num_neighbors

An integer specifying the number of neighbors for the Vecchia approximation

vecchia_ordering

A string specifying the ordering used in the Vecchia approximation. "none" means the default ordering is used, "random" uses a random ordering

vecchia_pred_type

A string specifying the type of Vecchia approximation used for making predictions. "order_obs_first_cond_obs_only" = observed data is ordered first and the neighbors are only observed points, "order_obs_first_cond_all" = observed data is ordered first and the neighbors are selected among all points (observed + predicted), "order_pred_first" = predicted data is ordered first for making predictions, "latent_order_obs_first_cond_obs_only" = Vecchia approximation for the latent process and observed data is ordered first and neighbors are only observed points, "latent_order_obs_first_cond_all" = Vecchia approximation for the latent process and observed data is ordered first and neighbors are selected among all points

num_neighbors_pred

an integer specifying the number of neighbors for the Vecchia approximation for making predictions

cluster_ids

A vector with elements indicating independent realizations of random effects / Gaussian processes (same values = same process realization). The elements of 'cluster_ids' can be integer, double, or character.

free_raw_data

A boolean. If TRUE, the data (groups, coordinates, covariate data for random coefficients) is freed in R after initialization

likelihood

A string specifying the likelihood function (distribution) of the response variable Default = "gaussian"

Author

Fabio Sigrist

Examples

Run this code
# See https://github.com/fabsig/GPBoost/tree/master/R-package for more examples

data(GPBoost_data, package = "gpboost")

#--------------------Grouped random effects model: single-level random effect----------------
gp_model <- GPModel(group_data = group_data[,1], likelihood="gaussian")

#--------------------Gaussian process model----------------
gp_model <- GPModel(gp_coords = coords, cov_function = "exponential",
                    likelihood="gaussian")

#--------------------Combine Gaussian process with grouped random effects----------------
gp_model <- GPModel(group_data = group_data,
                    gp_coords = coords, cov_function = "exponential",
                    likelihood="gaussian")

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