/*  tsolvps.c    CCMATH mathematics library source code.
 *
 *  Copyright (C)  2000   Daniel A. Atkinson    All rights reserved.
 *  This code may be redistributed under the terms of the GNU library
 *  public license (LGPL). ( See the lgpl.license file for details.)
 * ------------------------------------------------------------------------
 */
/*
    Test:  solvps

    Uses:  vmult  mcopy  matprt

    Input file:  spsol.dat
*/
#include "ccmath.h"
void main(int na,char **av)
{ int i,m,n; FILE *fp;
  double *p,*a,*x,*b,*y;
  if(na!=2){ printf("para: input_file\n"); exit(-1);}
  fp=fopen(*++av,"r");
  printf("Test of Symmetric Positive Definite Solver\n");
  fscanf(fp,"%d",&n); m=n*n;
  a=(double *)calloc(2*(m+n),sizeof(double));
  b=a+m; x=b+m; y=x+n;
  for(i=0,p=a; i<m ;++i) fscanf(fp,"%lf",p++);
  for(i=0,p=x; i<n ;++i) fscanf(fp,"%lf",p++);
  printf(" input matrix A:\n"); matprt(a,n,n,"%10f ");
  printf(" input vector x:\n"); matprt(x,1,n,"%10f ");
  mcopy(b,a,n*n);

/* solve the symmetric positive definite real linear system */
  i=solvps(a,x,n);

  if(i) printf(" matrix singular\n");
  else{ printf(" solution vector y:\n"); matprt(x,1,n,"%10f ");
/* check solution */
    vmul(y,b,x,n);
    printf(" check vector z=A*y\n"); matprt(y,1,n,"%10f ");
   }
}
/* Test output

Test of Symmetric Positive Definite Solver
 input matrix A:
  1.875000   0.625000   0.375000   1.125000 
  0.625000   1.875000   1.125000   0.375000 
  0.375000   1.125000   1.875000   0.625000 
  1.125000   0.375000   0.625000   1.875000 
 input vector x:
  0.500000   1.500000  -2.000000   2.500000 
 solution vector y:
 -1.781250   2.843750  -3.406250   2.968750 
 check vector z=A*y
  0.500000   1.500000  -2.000000   2.500000 
*/