add numerical recipes library

lib/nr/cpp/recipes/sprspm.cpp

@@ -0,0 +1,47 @@
+#include "nr.h"
+
+void NR::sprspm(Vec_I_DP &sa, Vec_I_INT &ija, Vec_I_DP &sb, Vec_I_INT &ijb,
+	Vec_O_DP &sc, Vec_I_INT &ijc)
+{
+	int i,ijma,ijmb,j,m,ma,mb,mbb,mn;
+	DP sum;
+
+	if (ija[0] != ijb[0] || ija[0] != ijc[0])
+		nrerror("sprspm: sizes do not match");
+	for (i=0;i<ijc[0]-1;i++) {
+		m=i+1;
+		j=m-1;
+		mn=ijc[i];
+		sum=sa[i]*sb[i];
+		for (;;) {
+			mb=ijb[j];
+			for (ma=ija[i];ma<ija[i+1];ma++) {
+				ijma=ija[ma];
+				if (ijma == j) sum += sa[ma]*sb[j];
+				else {
+					while (mb < ijb[j+1]) {
+						ijmb=ijb[mb];
+						if (ijmb == i) {
+							sum += sa[i]*sb[mb++];
+							continue;
+						} else if (ijmb < ijma) {
+							mb++;
+							continue;
+						} else if (ijmb == ijma) {
+							sum += sa[ma]*sb[mb++];
+							continue;
+						}
+						break;
+					}
+				}
+			}
+			for (mbb=mb;mbb<ijb[j+1];mbb++) {
+				if (ijb[mbb] == i) sum += sa[i]*sb[mbb];
+			}
+			sc[m-1]=sum;
+			sum=0.0;
+			if (mn >= ijc[i+1]) break;
+			j=ijc[(m= ++mn)-1];
+		}
+	}
+}