blas1C.c

/**
   @file      blas1C.c
   @author    Mitch Richling <http://www.mitchr.me/>
   @Copyright Copyright 1997 by Mitch Richling.  All rights reserved.
   @breif     Demonstrate Level 1 BLAS.@EOL
   @Keywords  blas cblas C FORTRAN numerical linear algebra vector matrix
   @Std       C89

              This is a simple program intended to illustrate how to
              make use of several level 1 blas functions found in the
              cblas (ATLAS).  Functions illustrated:

                  dswap     dscal      dcopy     daxpy
                  ddotu     ddotc      ddot      dnrm2
                  dasum     idmax
*/

#include <stdio.h>              /* I/O lib         ISOC  */
#include <stdlib.h>             /* Standard Lib    ISOC  */
#ifdef __APPLE__
#include <vecLib/cblas.h>    	/* C BLAS          APPLE */
#else
#include <cblas.h>              /* C BLAS          BLAS  */
#endif
#include "blaio.h"           /* Basic Linear Algebra I/O */

int main(int argc, char **argv) {
  double x[4] = {2, 3, 4, 5};
  double y[4] = {5, 4, 9, 2};
  double d[4];

  printVector(4, x, 3, 1, NULL, NULL, NULL, "            x = ");
  printVector(4, y, 3, 1, NULL, NULL, NULL, "            y = ");
   
           /* lenX X  incX Y  incY*/
  cblas_dswap(4,   x, 1,   y, 1);

  printf("After Swap..\n");
  printVector(4, x, 3, 1, NULL, NULL, NULL, "            x = ");
  printVector(4, y, 3, 1, NULL, NULL, NULL, "            y = ");

           /* lenX X  incX Y  incY*/
  cblas_dcopy(4,   x, 1,   d, 1);
  printf("After Copy (d=x)..\n");
  printVector(4, d, 3, 1, NULL, NULL, NULL, "       d <- x = ");


           /* lenX alpha X  incX */
  cblas_dscal(4,   2.0,  y, 1);
  printf("After Scale (2*y)..\n");
  printVector(4, y, 3, 1, NULL, NULL, NULL, "        2.0*y = ");

           /* lenX alpha X  incX y  incY*/
  cblas_daxpy(4,   3.0,  x, 1,   y, 1);
  printf("After Add (y=3*x+y)..\n");
  printVector(4, y, 3, 1, NULL, NULL, NULL, " y <- 3.0*x+y = ");
  
                                                     /* lenX X  incX */
  printf("2-norm   of y = %0.2f\n",  (float)cblas_dnrm2(4,   y, 1));
  printf("sum-norm of y = %0.2f\n",  (float)cblas_dasum(4,   y, 1));

  /* Note, the i#amax norm returns the INDEX of the element that
     corresponds to the max-norm value.                 lenX X  incX */
  printf("max-norm of y = |y[%d]|\n", (int)cblas_idamax(4,   y, 1));   

                                                     /* lenX X  incX Y  incY */
  printf("      y dot y = %0.2f\n",   (float)cblas_ddot(4,   y, 1,   y, 1));

  return 0;
} /* end func main */