Getting started with LBBNN

Introduction

LBBNN implements Latent Bayesian Binary Neural Networks in R using the torch framework. This vignette walks through basic usage: data preparation, model definition, training, validation, and visualization.

Setup

library(LBBNN)
library(ggplot2)
library(torch)

Data loaders

loaders <- get_dataloaders(Raisin_Dataset, train_proportion = 0.8,
                           train_batch_size = 720, test_batch_size = 180)
train_loader <- loaders$train_loader
test_loader  <- loaders$test_loader

Define the model

problem <- 'binary classification'
sizes <- c(7,5,5,1)
inclusion_priors <- c(0.5,0.5,0.5)
stds <- c(1,1,1)
inclusion_inits <- matrix(rep(c(-10,15),3), nrow = 2, ncol = 3)
device <- 'cpu'

torch_manual_seed(0)
model_input_skip <- LBBNN_Net(problem_type = problem, sizes = sizes, prior = inclusion_priors,
                              inclusion_inits = inclusion_inits, input_skip = TRUE, std = stds,
                              flow = FALSE, device = device)

Train

results_input_skip <- train_LBBNN(epochs = 50, LBBNN = model_input_skip,
                                  lr = 0.005, train_dl = train_loader, device = device)

Validate

validate_LBBNN(LBBNN = model_input_skip, num_samples = 100,
               test_dl = test_loader, device = device)

Plot structure and explanations

LBBNN_plot(model_input_skip, layer_spacing = 1, neuron_spacing = 1,
           vertex_size = 15, edge_width = 0.5)

x <- torch::dataloader_next(torch::dataloader_make_iter(train_loader))[[1]]
inds <- sample.int(dim(x)[1], 1)
data <- x[inds,]
plot_local_explanations_gradient(model_input_skip, data, num_samples = 100, device = device)

Note: All chunks in this vignette are non-evaluated by default to ensure fast builds and avoid backend constraints on CRAN/CI. You can set eval=TRUE locally.