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/qgaus.cpp
+++ b/lib/nr/cpp/recipes/qgaus.cpp
@@ -0,0 +1,20 @@
+#include "nr.h"
+
+DP NR::qgaus(DP func(const DP), const DP a, const DP b)
+{
+	static const DP x[]={0.1488743389816312,0.4333953941292472,
+		0.6794095682990244,0.8650633666889845,0.9739065285171717};
+	static const DP w[]={0.2955242247147529,0.2692667193099963,
+		0.2190863625159821,0.1494513491505806,0.0666713443086881};
+	int j;
+	DP xr,xm,dx,s;
+
+	xm=0.5*(b+a);
+	xr=0.5*(b-a);
+	s=0;
+	for (j=0;j<5;j++) {
+		dx=xr*x[j];
+		s += w[j]*(func(xm+dx)+func(xm-dx));
+	}
+	return s *= xr;
+}