add numerical recipes library

lib/nr/ansi/examples/xsimpr.c

@@ -0,0 +1,44 @@
+
+/* Driver for routine simpr */
+
+#include <stdio.h>
+#define NRANSI
+#include "nr.h"
+#include "nrutil.h"
+
+#define NVAR 3
+#define X1 0.0
+#define HTOT 50.0
+
+int main(void)
+{
+	int i;
+	float a1=0.5976,a2=1.4023,a3=0.0,*y,*yout,*dfdx,**dfdy,*dydx;
+
+	y=vector(1,NVAR);
+	yout=vector(1,NVAR);
+	dfdx=vector(1,NVAR);
+	dfdy=matrix(1,NVAR,1,NVAR);
+	dydx=vector(1,NVAR);
+	y[1]=y[2]=1.0;
+	y[3]=0.0;
+	derivs(X1,y,dydx);
+	jacobn(X1,y,dfdx,dfdy,NVAR);
+	printf("Test Problem:\n");
+	for (i=5;i<=50;i+=5) {
+		simpr(y,dydx,dfdx,dfdy,NVAR,X1,HTOT,i,yout,derivs);
+		printf("\n%s %5.2f %s %5.2f %s %2d %s \n",
+			"x=",X1," to ",X1+HTOT," in ",i," steps");
+		printf("%14s %9s\n","integration","bessj");
+		printf("%12.6f %12.6f\n",yout[1],a1);
+		printf("%12.6f %12.6f\n",yout[2],a2);
+		printf("%12.6f %12.6f\n",yout[3],a3);
+	}
+	free_vector(dydx,1,NVAR);
+	free_matrix(dfdy,1,NVAR,1,NVAR);
+	free_vector(dfdx,1,NVAR);
+	free_vector(yout,1,NVAR);
+	free_vector(y,1,NVAR);
+	return 0;
+}
+#undef NRANSI