add numerical recipes library

lib/nr/ansi/recipes/cholsl.c

@@ -0,0 +1,15 @@
+
+void cholsl(float **a, int n, float p[], float b[], float x[])
+{
+	int i,k;
+	float sum;
+
+	for (i=1;i<=n;i++) {
+		for (sum=b[i],k=i-1;k>=1;k--) sum -= a[i][k]*x[k];
+		x[i]=sum/p[i];
+	}
+	for (i=n;i>=1;i--) {
+		for (sum=x[i],k=i+1;k<=n;k++) sum -= a[k][i]*x[k];
+		x[i]=sum/p[i];
+	}
+}