#include <math.h>void sprstm(float sa[], unsigned long ija[], float sb[], unsigned long ijb[],	float thresh, unsigned long nmax, float sc[], unsigned long ijc[]){	void nrerror(char error_text[]);	unsigned long i,ijma,ijmb,j,k,ma,mb,mbb;	float sum;	if (ija[1] != ijb[1]) nrerror("sprstm: sizes do not match");	ijc[1]=k=ija[1];	for (i=1;i<=ija[1]-2;i++) {		for (j=1;j<=ijb[1]-2;j++) {			if (i == j) sum=sa[i]*sb[j]; else sum=0.0e0;			mb=ijb[j];			for (ma=ija[i];ma<=ija[i+1]-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]-1;mbb++) {				if (ijb[mbb] == i) sum += sa[i]*sb[mbb];			}			if (i == j) sc[i]=sum;			else if (fabs(sum) > thresh) {				if (k > nmax) nrerror("sprstm: nmax too small");				sc[k]=sum;				ijc[k++]=j;			}		}		ijc[i+1]=k;	}}