add numerical recipes library

lib/nr/ansi/recipes/rotate.c

@@ -0,0 +1,36 @@
+
+#include <math.h>
+#define NRANSI
+#include "nrutil.h"
+
+void rotate(float **r, float **qt, int n, int i, float a, float b)
+{
+	int j;
+	float c,fact,s,w,y;
+
+	if (a == 0.0) {
+		c=0.0;
+		s=(b >= 0.0 ? 1.0 : -1.0);
+	} else if (fabs(a) > fabs(b)) {
+		fact=b/a;
+		c=SIGN(1.0/sqrt(1.0+(fact*fact)),a);
+		s=fact*c;
+	} else {
+		fact=a/b;
+		s=SIGN(1.0/sqrt(1.0+(fact*fact)),b);
+		c=fact*s;
+	}
+	for (j=i;j<=n;j++) {
+		y=r[i][j];
+		w=r[i+1][j];
+		r[i][j]=c*y-s*w;
+		r[i+1][j]=s*y+c*w;
+	}
+	for (j=1;j<=n;j++) {
+		y=qt[i][j];
+		w=qt[i+1][j];
+		qt[i][j]=c*y-s*w;
+		qt[i+1][j]=s*y+c*w;
+	}
+}
+#undef NRANSI