add numerical recipes library

lib/nr/ansi/recipes/pwt.c

@@ -0,0 +1,51 @@
+
+#define NRANSI
+#include "nrutil.h"
+
+typedef struct {
+	int ncof,ioff,joff;
+	float *cc,*cr;
+} wavefilt;
+
+extern wavefilt wfilt;
+
+void pwt(float a[], unsigned long n, int isign)
+{
+	float ai,ai1,*wksp;
+	unsigned long i,ii,j,jf,jr,k,n1,ni,nj,nh,nmod;
+
+	if (n < 4) return;
+	wksp=vector(1,n);
+	nmod=wfilt.ncof*n;
+	n1=n-1;
+	nh=n >> 1;
+	for (j=1;j<=n;j++) wksp[j]=0.0;
+	if (isign >= 0) {
+		for (ii=1,i=1;i<=n;i+=2,ii++) {
+			ni=i+nmod+wfilt.ioff;
+			nj=i+nmod+wfilt.joff;
+			for (k=1;k<=wfilt.ncof;k++) {
+				jf=n1 & (ni+k);
+				jr=n1 & (nj+k);
+				wksp[ii] += wfilt.cc[k]*a[jf+1];
+				wksp[ii+nh] += wfilt.cr[k]*a[jr+1];
+			}
+		}
+	} else {
+		for (ii=1,i=1;i<=n;i+=2,ii++) {
+			ai=a[ii];
+			ai1=a[ii+nh];
+			ni=i+nmod+wfilt.ioff;
+			nj=i+nmod+wfilt.joff;
+			for (k=1;k<=wfilt.ncof;k++) {
+				jf=(n1 & (ni+k))+1;
+				jr=(n1 & (nj+k))+1;
+				wksp[jf] += wfilt.cc[k]*ai;
+				wksp[jr] += wfilt.cr[k]*ai1;
+			}
+		}
+	}
+	for (j=1;j<=n;j++) a[j]=wksp[j];
+	free_vector(wksp,1,n);
+}
+#undef NRANSI