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/sinft.cpp
+++ b/lib/nr/cpp/recipes/sinft.cpp
@@ -0,0 +1,32 @@
+#include <cmath>
+#include "nr.h"
+using namespace std;
+
+void NR::sinft(Vec_IO_DP &y)
+{
+	int j;
+	DP sum,y1,y2,theta,wi=0.0,wr=1.0,wpi,wpr,wtemp;
+
+	int n=y.size();
+	theta=3.141592653589793238/DP(n);
+	wtemp=sin(0.5*theta);
+	wpr= -2.0*wtemp*wtemp;
+	wpi=sin(theta);
+	y[0]=0.0;
+	for (j=1;j<(n>>1)+1;j++) {
+		wr=(wtemp=wr)*wpr-wi*wpi+wr;
+		wi=wi*wpr+wtemp*wpi+wi;
+		y1=wi*(y[j]+y[n-j]);
+		y2=0.5*(y[j]-y[n-j]);
+		y[j]=y1+y2;
+		y[n-j]=y1-y2;
+	}
+	realft(y,1);
+	y[0]*=0.5;
+	sum=y[1]=0.0;
+	for (j=0;j<n-1;j+=2) {
+		sum += y[j];
+		y[j]=y[j+1];
+		y[j+1]=sum;
+	}
+}