add numerical recipes library

lib/nr/ansi/recipes/daub4.c

@@ -0,0 +1,39 @@
+
+#define NRANSI
+#include "nrutil.h"
+#define C0 0.4829629131445341
+#define C1 0.8365163037378079
+#define C2 0.2241438680420134
+#define C3 -0.1294095225512604
+
+void daub4(float a[], unsigned long n, int isign)
+{
+	float *wksp;
+	unsigned long nh,nh1,i,j;
+
+	if (n < 4) return;
+	wksp=vector(1,n);
+	nh1=(nh=n >> 1)+1;
+	if (isign >= 0) {
+		for (i=1,j=1;j<=n-3;j+=2,i++) {
+			wksp[i]=C0*a[j]+C1*a[j+1]+C2*a[j+2]+C3*a[j+3];
+			wksp[i+nh] = C3*a[j]-C2*a[j+1]+C1*a[j+2]-C0*a[j+3];
+		}
+		wksp[i]=C0*a[n-1]+C1*a[n]+C2*a[1]+C3*a[2];
+		wksp[i+nh] = C3*a[n-1]-C2*a[n]+C1*a[1]-C0*a[2];
+	} else {
+		wksp[1]=C2*a[nh]+C1*a[n]+C0*a[1]+C3*a[nh1];
+		wksp[2] = C3*a[nh]-C0*a[n]+C1*a[1]-C2*a[nh1];
+		for (i=1,j=3;i<nh;i++) {
+			wksp[j++]=C2*a[i]+C1*a[i+nh]+C0*a[i+1]+C3*a[i+nh1];
+			wksp[j++] = C3*a[i]-C0*a[i+nh]+C1*a[i+1]-C2*a[i+nh1];
+		}
+	}
+	for (i=1;i<=n;i++) a[i]=wksp[i];
+	free_vector(wksp,1,n);
+}
+#undef C0
+#undef C1
+#undef C2
+#undef C3
+#undef NRANSI