Generate square of feature maps for nnet

featuremap.R

square_stack_lst_of_matricies <- function(lst)
{
    sqr_size <- sqrt(length(lst))
    # Stack vertically
    cols <- do.call(cbind, lst)
    # Split to another dim
    dim(cols) <- c(dim(filter_map[[1]])[[1]],
                   dim(filter_map[[1]])[[1]]*sqr_size,
                   sqr_size)
    # Stack horizontally
    do.call(rbind, lapply(1:dim(cols)[3], function(i) cols[, , i])) 
}