add numerical recipes library

lib/nr/k_and_r/recipes/wt1.c

@@ -0,0 +1,16 @@
+
+void wt1(a,n,isign,wtstep)
+float a[];
+int isign;
+unsigned long n;
+void (*wtstep)();
+{
+	unsigned long nn;
+
+	if (n < 4) return;
+	if (isign >= 0) {
+		for (nn=n;nn>=4;nn>>=1) (*wtstep)(a,nn,isign);
+	} else {
+		for (nn=4;nn<=n;nn<<=1) (*wtstep)(a,nn,isign);
+	}
+}