R/blockmult.R

In BigDataStatMeth: Statistical Methods and Algorithms for Big Data

#' Block matrix multiplication with Delayed Array Object
#' 
#' This function performs a block matrix-matrix multiplication with numeric matrix or Delayed Arrays
#' 
#' @export
#' 
#' @param A a double matrix.
#' @param B a double matrix.
#' @param block_size (optional, defalut = 128) block size to make matrix multiplication, if `block_size = 1` no block size is applied (size 1 = 1 element per block)
#' @param paral, (optional, default = TRUE) if paral = TRUE performs parallel computation else performs seria computation
#' @param threads (optional) only if bparal = true, number of concurrent threads in parallelization if threads is null then threads =  maximum number of threads available
#' @param bigmatrix (optiona, default = 5000) maximum number of rows or columns to consider as big matrix and work with
#' hdf5 files, by default a matrix with more than 5000 rows or files is considered big matrix and computation is made in disk 
#' @param mixblock_size (optiona, default = 128), only if we are working with big matrix and parallel computation = true. 
#' Block size for mixed computation in big matrix parallel. Size of the block to be used to perform parallelized memory 
#' memory of the block read from the disk being processed.
#' @param outfile (optional) file name to work with hdf5 if we are working with big matrix in disk.
#' @param onmemory (optional) if onmemory = TRUE the multiplication is forced to execute in memory
#' @return numerical matrix
#' @examples
#' # with numeric matrix
#' 
#' m <- 500
#' k <- 1500
#' n <- 400
#' A <- matrix(rnorm(n*k), nrow=n, ncol=k)
#' B <- matrix(rnorm(n*k), nrow=k, ncol=n)
#' 
#' C <- bdblockmult(A, B, 128, TRUE)
#' 
bdblockmult <- function( A, B, block_size = 128, paral = TRUE, threads = NULL, bigmatrix = 10000, mixblock_size = 128, 
                       outfile = "tmp_blockmult.hdf5", onmemory = FALSE)
{ 

  res <- .Call('_BigDataStatMeth_blockmult', PACKAGE = 'BigDataStatMeth', A, B, block_size, paral, threads, bigmatrix, mixblock_size, outfile, onmemory)

  if (res$filename == '' | is.null(res$filename))
    return (res$matrix)
  else
    return( list( "file" = res$filename, "dataset" = res$dataset) )

}