blas2bC.c

/* -*- Mode:C; Coding:us-ascii-unix; fill-column:132 -*- */
/* ****************************************************************************************************************************** */
/**
   @file      blas2bC.c
   @author    Mitch Richling <https://www.mitchr.me/>
   @Copyright Copyright 1997 by Mitch Richling.  All rights reserved.
   @brief     Demonstrate several cblas (level 1) functions. @EOL
   @Keywords  blas cblas C fortran numerical linear algebra vector matrix gemv ger
   @Std       C89

   This is a simple program intended to illustrate how to make use of #gemv and #ger blas routines (as implemented in the cblas).

   This is almost precisely the same as example program blas2.c; however, this one uses the column major order of Fortran.
              
*/

/* ------------------------------------------------------------------------------------------------------------------------------ */

#include <stdio.h>              /* I/O lib         ISOC     */
#include <stdlib.h>             /* Standard Lib    ISOC     */
#include "blaio.h"              /* Basic Linear Algebra I/O */

int main(int argc, char **argv) {
  double a[4*5] = {  1,  6, 11, 16,
                     2,  7, 12, 17,
                     3,  8, 13, 18,
                     4,  9, 14, 19,
                     5, 10, 15, 20 };
  double x[5]  = {2,3,4,5,6};
  double y[4];

   printMatrix(CblasColMajor, 4, 5, a, 8, 3, NULL, NULL, NULL, NULL, NULL, "              a = ");
   printVector(5, x, 8, 3, NULL, NULL, NULL, "              x = ");

            /* row_order      transform     lenY lenX alpha  a  lda  X  incX  beta  Y, incY */
   cblas_dgemv(CblasColMajor, CblasNoTrans, 4,   5,   1,     a,   4, x, 1,    0,    y, 1);
   printVector(4, y, 8, 3, NULL, NULL, NULL, "       y<-1.0*a*xT+0.0*y= ");

           /* row_order       lenY lenX alpha  X  incX  Y, incY A  LDA */
   cblas_dger(CblasColMajor,  4,   5,   1,     y, 1,    x, 1,   a, 4);
   printMatrix(CblasColMajor, 4, 5, a, 8, 3, NULL, NULL, NULL, NULL, NULL, "a <- 1.0*x.yT+a = ");

   return 0;
} /* end func main*/