R/ddmatrix_norm.r

In RBigData/pbdDMAT: 'pbdR' Distributed Matrix Methods

#' Norm
#' 
#' Computes the norm of a distributed matrix.
#' 
#' @param x 
#' numeric distributed matrices.
#' @param type 
#' character. Determines which matrix norm is to be used.
#' 
#' @return Returns a number.
#' 
#' @keywords Methods Linear Algebra Norm
#' @aliases norm
#' @section Methods: \describe{ \item{list("signature(x = \"ddmatrix\")")}{} }
#' @name ddmatrix-norm
#' @rdname ddmatrix-norm
NULL

#' @rdname ddmatrix-norm
#' @export
setMethod("norm", signature(x="ddmatrix"), 
  function (x, type = c("O", "I", "F", "M", "2")) 
  {
    if (identical("2", type))
      ret <- svd(x, nu = 0L, nv = 0L)$d[1L]
    else {
      m <- x@dim[1L]
      n <- x@dim[2L]
      
      desca <- base.descinit(dim=x@dim, bldim=x@bldim, ldim=x@ldim, ICTXT=x@ICTXT)
      
      ret <- base.rpdlange(norm=type, m=m, n=n, a=x@Data, desca=desca)
    }
    
    return( ret )
  }
)