add numerical recipes library

lib/nr/ansi/examples/xdftint.c

@@ -0,0 +1,52 @@
+
+/* Driver for routine dftint */
+
+#include <stdio.h>
+#include <math.h>
+#define NRANSI
+#include "nr.h"
+
+static float c,d;
+
+float coscxd(float x)
+{
+	return cos(c*x+d);
+}
+
+#define ci(x) (sin((w-c)*x-d)/(2.0*(w-c))+sin((w+c)*x+d)/(2.0*(w+c)))
+#define si(x) (-cos((w-c)*x-d)/(2.0*(w-c))-cos((w+c)*x+d)/(2.0*(w+c)))
+
+void getans(float w,float a,float b,float *cans,float *sans)
+{
+	*cans=ci(b)-ci(a);
+	*sans=si(b)-si(a);
+}
+
+int main(void)
+{
+	float a,b,cans,cosint,sans,sinint,w;
+
+	printf("  Omega  Integral cosine*test func  Err");
+	printf("    Integral sine*test func   Err\n");
+	for (;;) {
+		printf("input c,d:\n");
+		if (scanf("%f %f",&c,&d) == EOF) break;
+		for (;;) {
+			printf("input a,b:\n");
+			if (scanf("%f %f",&a,&b) == EOF) break;
+			if (a == b) break;
+				for (;;) {
+					printf("input w:\n");
+					if (scanf("%f",&w) == EOF) break;
+					if (w < 0.0) break;
+					dftint(coscxd,a,b,w,&cosint,&sinint);
+					getans(w,a,b,&cans,&sans);
+					printf("%15.6e %15.6e %15.6e %15.6e %15.6e\n",
+						w,cans,cosint-cans,sans,sinint-sans);
+				}
+		}
+	}
+	printf("normal completion\n");
+	return 0;
+}
+#undef NRANSI