add numerical recipes library

lib/nr/ansi/recipes/sort2.c

@@ -0,0 +1,83 @@
+
+#define NRANSI
+#include "nrutil.h"
+#define SWAP(a,b) temp=(a);(a)=(b);(b)=temp;
+#define M 7
+#define NSTACK 50
+
+void sort2(unsigned long n, float arr[], float brr[])
+{
+	unsigned long i,ir=n,j,k,l=1,*istack;
+	int jstack=0;
+	float a,b,temp;
+
+	istack=lvector(1,NSTACK);
+	for (;;) {
+		if (ir-l < M) {
+			for (j=l+1;j<=ir;j++) {
+				a=arr[j];
+				b=brr[j];
+				for (i=j-1;i>=l;i--) {
+					if (arr[i] <= a) break;
+					arr[i+1]=arr[i];
+					brr[i+1]=brr[i];
+				}
+				arr[i+1]=a;
+				brr[i+1]=b;
+			}
+			if (!jstack) {
+				free_lvector(istack,1,NSTACK);
+				return;
+			}
+			ir=istack[jstack];
+			l=istack[jstack-1];
+			jstack -= 2;
+		} else {
+			k=(l+ir) >> 1;
+			SWAP(arr[k],arr[l+1])
+			SWAP(brr[k],brr[l+1])
+			if (arr[l] > arr[ir]) {
+				SWAP(arr[l],arr[ir])
+				SWAP(brr[l],brr[ir])
+			}
+			if (arr[l+1] > arr[ir]) {
+				SWAP(arr[l+1],arr[ir])
+				SWAP(brr[l+1],brr[ir])
+			}
+			if (arr[l] > arr[l+1]) {
+				SWAP(arr[l],arr[l+1])
+				SWAP(brr[l],brr[l+1])
+			}
+			i=l+1;
+			j=ir;
+			a=arr[l+1];
+			b=brr[l+1];
+			for (;;) {
+				do i++; while (arr[i] < a);
+				do j--; while (arr[j] > a);
+				if (j < i) break;
+				SWAP(arr[i],arr[j])
+				SWAP(brr[i],brr[j])
+			}
+			arr[l+1]=arr[j];
+			arr[j]=a;
+			brr[l+1]=brr[j];
+			brr[j]=b;
+			jstack += 2;
+			if (jstack > NSTACK) nrerror("NSTACK too small in sort2.");
+			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;
+			}
+		}
+	}
+}
+#undef M
+#undef NSTACK
+#undef SWAP
+#undef NRANSI