add numerical recipes library

2025-09-12 18:55:25 +09:00
parent d4dff245bd
commit 2c75620ec9
1344 changed files with 63869 additions and 0 deletions
--- a/lib/nr/cpp/recipes/factln.cpp
+++ b/lib/nr/cpp/recipes/factln.cpp
@@ -0,0 +1,12 @@
+#include "nr.h"
+
+DP NR::factln(const int n)
+{
+	static DP a[101];
+
+	if (n < 0) nrerror("Negative factorial in routine factln");
+	if (n <= 1) return 0.0;
+	if (n <= 100)
+		return (a[n] != 0.0 ? a[n] : (a[n]=gammln(n+1.0)));
+	else return gammln(n+1.0);
+}