add numerical recipes library

lib/nr/ansi/examples/xludcmp.c

@@ -0,0 +1,109 @@
+
+/* Driver for routine ludcmp */
+
+#include <stdio.h>
+#include <stdlib.h>
+#define NRANSI
+#include "nr.h"
+#include "nrutil.h"
+
+#define NP 20
+#define MAXSTR 80
+
+int main(void)
+{
+	int j,k,l,m,n,dum,*indx,*jndx;
+	float d,**a,**xl,**xu,**x;
+	char dummy[MAXSTR];
+	FILE *fp;
+
+	indx=ivector(1,NP);
+	jndx=ivector(1,NP);
+	a=matrix(1,NP,1,NP);
+	xl=matrix(1,NP,1,NP);
+	xu=matrix(1,NP,1,NP);
+	x=matrix(1,NP,1,NP);
+	if ((fp = fopen("matrx1.dat","r")) == NULL)
+		nrerror("Data file matrx1.dat not found\n");
+	while (!feof(fp)) {
+		fgets(dummy,MAXSTR,fp);
+		fgets(dummy,MAXSTR,fp);
+		fscanf(fp,"%d %d ",&n,&m);
+		fgets(dummy,MAXSTR,fp);
+		for (k=1;k<=n;k++)
+			for (l=1;l<=n;l++) fscanf(fp,"%f ",&a[k][l]);
+		fgets(dummy,MAXSTR,fp);
+		for (l=1;l<=m;l++)
+			for (k=1;k<=n;k++) fscanf(fp,"%f ",&x[k][l]);
+		/* Print out a-matrix for comparison with product of
+		   lower and upper decomposition matrices */
+		printf("original matrix:\n");
+		for (k=1;k<=n;k++) {
+			for (l=1;l<=n;l++) printf("%12.6f",a[k][l]);
+			printf("\n");
+		}
+		/* Perform the decomposition */
+		ludcmp(a,n,indx,&d);
+		/* Compose separately the lower and upper matrices */
+		for (k=1;k<=n;k++) {
+			for (l=1;l<=n;l++) {
+				if (l > k) {
+					xu[k][l]=a[k][l];
+					xl[k][l]=0.0;
+				} else if (l < k) {
+					xu[k][l]=0.0;
+					xl[k][l]=a[k][l];
+				} else {
+					xu[k][l]=a[k][l];
+					xl[k][l]=1.0;
+				}
+			}
+		}
+		/* Compute product of lower and upper matrices for
+		   comparison with original matrix */
+		for (k=1;k<=n;k++) {
+			jndx[k]=k;
+			for (l=1;l<=n;l++) {
+				x[k][l]=0.0;
+				for (j=1;j<=n;j++)
+					x[k][l] += (xl[k][j]*xu[j][l]);
+			}
+		}
+		printf("\n%s%s\n","product of lower and upper ",
+			 "matrices (rows unscrambled):");
+		for (k=1;k<=n;k++) {
+			dum=jndx[indx[k]];
+			jndx[indx[k]]=jndx[k];
+			jndx[k]=dum;
+		}
+		for (k=1;k<=n;k++)
+			for (j=1;j<=n;j++)
+				if (jndx[j] == k) {
+					for (l=1;l<=n;l++)
+						printf("%12.6f",x[j][l]);
+					printf("\n");
+				}
+		printf("\nlower matrix of the decomposition:\n");
+		for (k=1;k<=n;k++) {
+			for (l=1;l<=n;l++) printf("%12.6f",xl[k][l]);
+			printf("\n");
+		}
+		printf("\nupper matrix of the decomposition:\n");
+		for (k=1;k<=n;k++) {
+			for (l=1;l<=n;l++) printf("%12.6f",xu[k][l]);
+			printf("\n");
+		}
+		printf("\n***********************************\n");
+		printf("press return for next problem:\n");
+		(void) getchar();
+	}
+	fclose(fp);
+	free_matrix(x,1,NP,1,NP);
+	free_matrix(xu,1,NP,1,NP);
+	free_matrix(xl,1,NP,1,NP);
+	free_matrix(a,1,NP,1,NP);
+	free_ivector(jndx,1,NP);
+	free_ivector(indx,1,NP);
+	return 0;
+}
+#undef NRANSI