add numerical recipes library

lib/nr/cpp/recipes/sort.cpp

@@ -0,0 +1,61 @@
+#include "nr.h"
+
+void NR::sort(Vec_IO_DP &arr)
+{
+	const int M=7,NSTACK=50;
+	int i,ir,j,k,jstack=-1,l=0;
+	DP a;
+	Vec_INT istack(NSTACK);
+
+	int n=arr.size();
+	ir=n-1;
+	for (;;) {
+		if (ir-l < M) {
+			for (j=l+1;j<=ir;j++) {
+				a=arr[j];
+				for (i=j-1;i>=l;i--) {
+					if (arr[i] <= a) break;
+					arr[i+1]=arr[i];
+				}
+				arr[i+1]=a;
+			}
+			if (jstack < 0) break;
+			ir=istack[jstack--];
+			l=istack[jstack--];
+		} else {
+			k=(l+ir) >> 1;
+			SWAP(arr[k],arr[l+1]);
+			if (arr[l] > arr[ir]) {
+				SWAP(arr[l],arr[ir]);
+			}
+			if (arr[l+1] > arr[ir]) {
+				SWAP(arr[l+1],arr[ir]);
+			}
+			if (arr[l] > arr[l+1]) {
+				SWAP(arr[l],arr[l+1]);
+			}
+			i=l+1;
+			j=ir;
+			a=arr[l+1];
+			for (;;) {
+				do i++; while (arr[i] < a);
+				do j--; while (arr[j] > a);
+				if (j < i) break;
+				SWAP(arr[i],arr[j]);
+			}
+			arr[l+1]=arr[j];
+			arr[j]=a;
+			jstack += 2;
+			if (jstack >= NSTACK) nrerror("NSTACK too small in sort.");
+			if (ir-i+1 >= j-l) {
+				istack[jstack]=ir;
+				istack[jstack-1]=i;
+				ir=j-1;
+			} else {
+				istack[jstack]=j-1;
+				istack[jstack-1]=l;
+				l=i;
+			}
+		}
+	}
+}