116 lines
2.6 KiB
C
116 lines
2.6 KiB
C
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/* Driver for routine qrdcmp */
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#include <stdio.h>
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#include <stdlib.h>
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#define NRANSI
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#include "nr.h"
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#include "nrutil.h"
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#define NP 20
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#define MAXSTR 80
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int main(void)
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{
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int i,j,k,l,m,n,sing;
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float con,**a,*c,*d,**q,**qt,**r,**x;
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char dummy[MAXSTR];
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FILE *fp;
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a=matrix(1,NP,1,NP);
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c=vector(1,NP);
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d=vector(1,NP);
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q=matrix(1,NP,1,NP);
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qt=matrix(1,NP,1,NP);
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r=matrix(1,NP,1,NP);
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x=matrix(1,NP,1,NP);
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if ((fp = fopen("matrx1.dat","r")) == NULL)
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nrerror("Data file matrx1.dat not found\n");
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while (!feof(fp)) {
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fgets(dummy,MAXSTR,fp);
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fgets(dummy,MAXSTR,fp);
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fscanf(fp,"%d %d ",&n,&m);
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fgets(dummy,MAXSTR,fp);
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for (k=1;k<=n;k++)
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for (l=1;l<=n;l++) fscanf(fp,"%f ",&a[k][l]);
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fgets(dummy,MAXSTR,fp);
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for (l=1;l<=m;l++)
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for (k=1;k<=n;k++) fscanf(fp,"%f ",&x[k][l]);
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/* Print out a-matrix for comparison with product of
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Q and R decomposition matrices */
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printf("Original matrix:\n");
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for (k=1;k<=n;k++) {
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for (l=1;l<=n;l++) printf("%12.6f",a[k][l]);
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printf("\n");
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}
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/* Perform the decomposition */
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qrdcmp(a,n,c,d,&sing);
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if (sing) fprintf(stderr,"Singularity in QR decomposition.\n");
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/* find the Q and R matrices */
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for (k=1;k<=n;k++) {
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for (l=1;l<=n;l++) {
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if (l > k) {
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r[k][l]=a[k][l];
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q[k][l]=0.0;
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} else if (l < k) {
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r[k][l]=q[k][l]=0.0;
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} else {
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r[k][l]=d[k];
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q[k][l]=1.0;
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}
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}
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}
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for (i=n-1;i>=1;i--) {
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for (con=0.0,k=i;k<=n;k++) con += a[k][i]*a[k][i];
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con /= 2.0;
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for (k=i;k<=n;k++) {
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for (l=i;l<=n;l++) {
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qt[k][l]=0.0;
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for (j=i;j<=n;j++) {
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qt[k][l] += q[j][l]*a[k][i]*a[j][i]/con;
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}
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}
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}
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for (k=i;k<=n;k++)
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for (l=i;l<=n;l++) q[k][l] -= qt[k][l];
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}
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/* compute product of Q and R matrices for comparison
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with original matrix. */
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for (k=1;k<=n;k++) {
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for (l=1;l<=n;l++) {
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x[k][l]=0.0;
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for (j=1;j<=n;j++)
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x[k][l] += q[k][j]*r[j][l];
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}
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}
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printf("\nProduct of Q and R matrices:\n");
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for (k=1;k<=n;k++) {
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for (l=1;l<=n;l++) printf("%12.6f",x[k][l]);
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printf("\n");
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}
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printf("\nQ matrix of the decomposition:\n");
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for (k=1;k<=n;k++) {
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for (l=1;l<=n;l++) printf("%12.6f",q[k][l]);
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printf("\n");
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}
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printf("\nR matrix of the decomposition:\n");
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for (k=1;k<=n;k++) {
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for (l=1;l<=n;l++) printf("%12.6f",r[k][l]);
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printf("\n");
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}
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printf("\n***********************************\n");
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printf("press return for next problem:\n");
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(void) getchar();
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}
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fclose(fp);
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free_matrix(x,1,NP,1,NP);
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free_matrix(r,1,NP,1,NP);
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free_matrix(qt,1,NP,1,NP);
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free_matrix(q,1,NP,1,NP);
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free_vector(d,1,NP);
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free_vector(c,1,NP);
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free_matrix(a,1,NP,1,NP);
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return 0;
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}
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#undef NRANSI
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