int eigs_sym_part (int ni, const float * a, int nev, float * sout, float * vout) {
FINTEGER n=ni;
arpack_eigs_t *ae=arpack_eigs_begin(n,nev);
int ret=0;
for(;;) {
float *x,*y;
ret=arpack_eigs_step(ae,&x,&y);
if(ret<0) break; /* error */
if(ret==0) break; /* stop iteration */
/* ret==1 */
float zero=0,one=1;
FINTEGER ione=1;
sgemv_("Trans",&n,&n,&one,a,&n,x,&ione,&zero,y,&ione);
}
ret=arpack_eigs_end(ae,sout,vout);
return ret;
}
int fmat_svd_partial_full(int n,int m,int nev,const float *a,int a_transposed,
float *s,float *vout,float *uout,int nt) {
arpack_eigs_t *ae=arpack_eigs_begin(n,nev);
if(!ae) return -100;
int ret=0;
int j,i;
float *ax=NEWA(float,m);
int it;
for(it=0;;it++) {
float *x,*y;
ret=arpack_eigs_step(ae,&x,&y);
printf("arpack iteration %d ret=%d\r",it,ret);
if(ret<0) break; /* error */
if(ret==0) break; /* stop iteration */
/* ret==1 */
if(!a_transposed) {
fmat_mul_v(m,n,a,n,x,ax,nt);
fmat_mul_tv(n,m,a,n,ax,y,nt);
} else {
fmat_mul_tv(m,n,a,m,x,ax,nt);
fmat_mul_v(n,m,a,m,ax,y,nt);
}
fflush(stdout);
}
printf("\n");
free(ax);
float *v=vout ? vout : fmat_new(nev,n);
ret=arpack_eigs_end(ae,s,v);
if(ret>0) {
int nconv=ret;
if(s)
for(j=0;j<nconv;j++)
s[j]=sqrt(s[j]);
if(uout)
for(i=0;i<nconv;i++) {
float *u=uout+m*(long)i;
if(!a_transposed)
fmat_mul_v(m,n,a,n,v+n*(long)i,u,nt);
else
fmat_mul_tv(m,n,a,m,v+n*(long)i,u,nt);
fvec_normalize(u,m,2);
}
}
if(!vout) free(v);
return ret;
}