#' @title Reshape array
#' @description Reshapes a matrix according to a certain number of dimensions
#' @param A input matrix
#' @param sz vector containing the dimensions of the output vector
#' @details This function replicates the functionality of the `reshape()`
#' function on Matlab. This function is basically a fancy wrapper for the
#' `array()` function in R, but is useful because it saves the user translation
#' time. Moreover, it introduces validation code that alter the behavior of
#' `array()` and makes it more similar to `replicate()`.
#' @note The Matlab function also accepts as input the dismemberment of sz as
#' scalars.
reshape <- function(A, sz) {
    # Validation
    if (prod(sz) != prod(dim(A))) {
        stop("To RESHAPE the number of elements must not change.")
    }
    if (length(sz) == 1) {
        stop("Size vector must have at least two elements.")
    }

    # Reshaping A
    A <- array(A, sz)
    return(A)
}