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/ran0.cpp
+++ b/lib/nr/cpp/recipes/ran0.cpp
@@ -0,0 +1,18 @@
+#include "nr.h"
+
+DP NR::ran0(int &idum)
+{
+	const int IA=16807,IM=2147483647,IQ=127773;
+	const int IR=2836,MASK=123459876;
+	const DP AM=1.0/DP(IM);
+	int k;
+	DP ans;
+
+	idum ^= MASK;
+	k=idum/IQ;
+	idum=IA*(idum-k*IQ)-IR*k;
+	if (idum < 0) idum += IM;
+	ans=AM*idum;
+	idum ^= MASK;
+	return ans;
+}