add numerical recipes library

lib/nr/cpp/recipes/spctrm.cpp

@@ -0,0 +1,62 @@
+#include <fstream>
+#include <cmath>
+#include "nr.h"
+using namespace std;
+
+namespace {
+	inline DP window(const int j, const DP a, const DP b)
+	{
+		return 1.0-fabs((j-a)*b);     // Bartlett
+		// return 1.0;                // Square
+		// return 1.0-SQR((j-a)*b);   // Welch
+	}
+}
+
+void NR::spctrm(ifstream &fp, Vec_O_DP &p, const int k, const bool ovrlap)
+{
+	int mm,m4,kk,joffn,joff,j2,j;
+	DP w,facp,facm,sumw=0.0,den=0.0;
+
+	int m=p.size();
+	mm=m << 1;
+	m4=mm << 1;
+	Vec_DP w1(m4),w2(m);
+	facm=m;
+	facp=1.0/m;
+	for (j=0;j<mm;j++)
+		sumw += SQR(window(j,facm,facp));
+	for (j=0;j<m;j++) p[j]=0.0;
+	if (ovrlap)
+		for (j=0;j<m;j++)
+			fp >> w2[j];
+	for (kk=0;kk<k;kk++) {
+		for (joff=0;joff<2;joff++) {
+			if (ovrlap) {
+				for (j=0;j<m;j++) w1[joff+j+j]=w2[j];
+				for (j=0;j<m;j++)
+					fp >> w2[j];
+				joffn=joff+mm-1;
+				for (j=0;j<m;j++) w1[joffn+j+j+1]=w2[j];
+			} else {
+				for (j=joff;j<m4;j+=2)
+					fp >> w1[j];
+			}
+		}
+		for (j=0;j<mm;j++) {
+			j2=j+j;
+			w=window(j,facm,facp);
+			w1[j2+1] *= w;
+			w1[j2] *= w;
+		}
+		four1(w1,1);
+		p[0] += (SQR(w1[0])+SQR(w1[1]));
+		for (j=1;j<m;j++) {
+			j2=j+j;
+			p[j] += (SQR(w1[j2+1])+SQR(w1[j2])
+				+SQR(w1[m4-j2+1])+SQR(w1[m4-j2]));
+		}
+		den += sumw;
+	}
+	den *= m4;
+	for (j=0;j<m;j++) p[j] /= den;
+}