#include "pdsp_defs.h"
#include "util.h"
#if ( MACH==CRAY_PVP )
fortran void STRSM(_fcd, _fcd, _fcd, _fcd, int*, int*, double*,
double*, int*, double*, int*);
fortran void SGEMM(_fcd, _fcd, int*, int*, int*, double*, double*,
int*, double*, int*, double*, double*, int*);
#endif
void
dgstrs(trans_t trans, SuperMatrix *L, SuperMatrix *U,
int *perm_r, int *perm_c, SuperMatrix *B, Gstat_t *Gstat, int *info)
{
/*
* -- SuperLU MT routine (version 1.0) --
* Univ. of California Berkeley, Xerox Palo Alto Research Center,
* and Lawrence Berkeley National Lab.
* August 15, 1997
*
* Purpose
* =======
*
* dgstrs() solves a system of linear equations A*X=B or A'*X=B
* with A sparse and B dense, using the LU factorization computed by
* pdgstrf().
*
* Arguments
* =========
*
* trans (input) Specifies the form of the system of equations:
* = NOTRANS: A * X = B (No transpose)
* = TRANS: A'* X = B (Transpose)
*
* L (input) SuperMatrix*
* The factor L from the factorization Pr*A*Pc=L*U as computed by
* pdgstrf(). Use compressed row subscripts storage for supernodes,
* i.e., L has types: Stype = SCP, Dtype = _D, Mtype = TRLU.
*
* U (input) SuperMatrix*
* The factor U from the factorization Pr*A*Pc=L*U as computed by
* pdgstrf(). Use column-wise storage scheme, i.e., U has types:
* Stype = NCP, Dtype = _D, Mtype = TRU.
*
* perm_r (input) int*
* Row permutation vector of size L->nrow, which defines the
* permutation matrix Pr; perm_r[i] = j means row i of A is in
* position j in Pr*A.
*
* perm_c (int*) dimension A->ncol
* Column permutation vector, which defines the
* permutation matrix Pc; perm_c[i] = j means column i of A is
* in position j in A*Pc.
*
* B (input/output) SuperMatrix*
* B has types: Stype = DN, Dtype = _D, Mtype = GE.
* On entry, the right hand side matrix.
* On exit, the solution matrix if info = 0;
*
* Gstat (output) Gstat_t*
* Record all the statistics about the triangular solves;
* See Gstat_t structure defined in util.h.
*
* info (output) Diagnostics
* = 0: successful exit
* < 0: if info = -i, the i-th argument had an illegal value
*
*/
#if ( MACH==CRAY_PVP )
_fcd ftcs1, ftcs2, ftcs3, ftcs4;
#endif
#ifdef USE_VENDOR_BLAS
int incx = 1, incy = 1;
double alpha = 1.0, beta = 1.0;
#endif
register int j, k, jcol, iptr, luptr, ksupno, istart, irow, bptr;
register int fsupc, nsuper;
int i, n, nsupc, nsupr, nrow, nrhs, ldb;
int *supno;
DNformat *Bstore;
SCPformat *Lstore;
NCPformat *Ustore;
double *Lval, *Uval, *Bmat;
double *work, *work_col, *rhs_work, *soln;
flops_t solve_ops;
void print_soln();
/* Test input parameters ... */
*info = 0;
Bstore = B->Store;
ldb = Bstore->lda;
nrhs = B->ncol;
if ( trans != NOTRANS && trans != TRANS ) *info = -1;
else if ( L->nrow != L->ncol || L->nrow < 0 ) *info = -3;
else if ( U->nrow != U->ncol || U->nrow < 0 ) *info = -4;
else if ( ldb < MAX(0, L->nrow) ) *info = -6;
if ( *info ) {
i = -(*info);
xerbla_("dgstrs", &i);
return;
}
n = L->nrow;
work = doubleCalloc(n * nrhs);
if ( !work ) ABORT("Malloc fails for local work[].");
soln = doubleMalloc(n);
if ( !soln ) ABORT("Malloc fails for local soln[].");
Bmat = Bstore->nzval;
Lstore = L->Store;
Lval = Lstore->nzval;
Ustore = U->Store;
Uval = Ustore->nzval;
supno = Lstore->col_to_sup;
nsuper = Lstore->nsuper;
solve_ops = 0;
if ( trans == NOTRANS ) {
/* Permute right hand sides to form Pr*B */
for (i = 0, bptr = 0; i < nrhs; i++, bptr += ldb) {
rhs_work = &Bmat[bptr];
for (k = 0; k < n; k++) soln[perm_r[k]] = rhs_work[k];
for (k = 0; k < n; k++) rhs_work[k] = soln[k];
}
/* Forward solve PLy=Pb. */
/*>> for (k = 0; k < n; k += nsupc) {
ksupno = supno[k];
*/
for (ksupno = 0; ksupno <= nsuper; ++ksupno) {
fsupc = L_FST_SUPC(ksupno);
istart = L_SUB_START(fsupc);
nsupr = L_SUB_END(fsupc) - istart;
nsupc = L_LAST_SUPC(ksupno) - fsupc;
nrow = nsupr - nsupc;
solve_ops += nsupc * (nsupc - 1) * nrhs;
solve_ops += 2 * nrow * nsupc * nrhs;
if ( nsupc == 1 ) {
for (j = 0, bptr = 0; j < nrhs; j++, bptr += ldb) {
rhs_work = &Bmat[bptr];
luptr = L_NZ_START(fsupc);
for (iptr=istart+1; iptr < L_SUB_END(fsupc); iptr++){
irow = L_SUB(iptr);
++luptr;
rhs_work[irow] -= rhs_work[fsupc] * Lval[luptr];
}
}
} else {
luptr = L_NZ_START(fsupc);
#ifdef USE_VENDOR_BLAS
#if ( MACH==CRAY_PVP )
ftcs1 = _cptofcd("L", strlen("L"));
ftcs2 = _cptofcd("N", strlen("N"));
ftcs3 = _cptofcd("U", strlen("U"));
STRSM(ftcs1, ftcs1, ftcs2, ftcs3, &nsupc, &nrhs, &alpha,
&Lval[luptr], &nsupr, &Bmat[fsupc], &ldb);
SGEMM(ftcs2, ftcs2, &nrow, &nrhs, &nsupc, &alpha,
&Lval[luptr+nsupc], &nsupr, &Bmat[fsupc], &ldb,
&beta, &work[0], &n );
#else
dtrsm_("L", "L", "N", "U", &nsupc, &nrhs, &alpha,
&Lval[luptr], &nsupr, &Bmat[fsupc], &ldb);
dgemm_( "N", "N", &nrow, &nrhs, &nsupc, &alpha,
&Lval[luptr+nsupc], &nsupr, &Bmat[fsupc], &ldb,
&beta, &work[0], &n );
#endif
for (j = 0, bptr = 0; j < nrhs; j++, bptr += ldb) {
rhs_work = &Bmat[bptr];
work_col = &work[j*n];
iptr = istart + nsupc;
for (i = 0; i < nrow; i++) {
irow = L_SUB(iptr);
rhs_work[irow] -= work_col[i]; /* Scatter */
work_col[i] = 0.0;
iptr++;
}
}
#else
for (j = 0, bptr = 0; j < nrhs; j++, bptr += ldb) {
rhs_work = &Bmat[bptr];
dlsolve (nsupr, nsupc, &Lval[luptr], &rhs_work[fsupc]);
dmatvec (nsupr, nrow, nsupc, &Lval[luptr+nsupc],
&rhs_work[fsupc], &work[0] );
iptr = istart + nsupc;
for (i = 0; i < nrow; i++) {
irow = L_SUB(iptr);
rhs_work[irow] -= work[i];
work[i] = 0.0;
iptr++;
}
}
#endif
} /* if-else: nsupc == 1 ... */
} /* for L-solve */
#if ( DEBUGlevel>=2 )
printf("After L-solve: y=\n");
print_soln(n, nrhs, Bmat);
#endif
/*
* Back solve Ux=y.
*/
/*>> for (k = n-1; k >= 0; k -= nsupc) {
ksupno = supno[k];
*/
for (ksupno = nsuper; ksupno >= 0; --ksupno) {
fsupc = L_FST_SUPC(ksupno);
istart = L_SUB_START(fsupc);
nsupr = L_SUB_END(fsupc) - istart;
nsupc = L_LAST_SUPC(ksupno) - fsupc;
luptr = L_NZ_START(fsupc);
solve_ops += nsupc * (nsupc + 1) * nrhs;
/* dense triangular matrix */
if ( nsupc == 1 ) {
rhs_work = &Bmat[0];
for (j = 0; j < nrhs; j++) {
rhs_work[fsupc] /= Lval[luptr];
rhs_work += ldb;
}
} else {
#ifdef USE_VENDOR_BLAS
#if ( MACH==CRAY_PVP )
ftcs1 = _cptofcd("L", strlen("L"));
ftcs2 = _cptofcd("U", strlen("U"));
ftcs3 = _cptofcd("N", strlen("N"));
STRSM(ftcs1, ftcs2, ftcs3, ftcs3, &nsupc, &nrhs, &alpha,
&Lval[luptr], &nsupr, &Bmat[fsupc], &ldb);
#else
dtrsm_("L", "U", "N", "N", &nsupc, &nrhs, &alpha,
&Lval[luptr], &nsupr, &Bmat[fsupc], &ldb);
#endif
#else
for (j = 0, bptr = fsupc; j < nrhs; j++, bptr += ldb) {
dusolve (nsupr, nsupc, &Lval[luptr], &Bmat[bptr]);
}
#endif
}
/* matrix-vector update */
for (j = 0, bptr = 0; j < nrhs; ++j, bptr += ldb) {
rhs_work = &Bmat[bptr];
for (jcol = fsupc; jcol < fsupc + nsupc; jcol++) {
solve_ops += 2*(U_NZ_END(jcol) - U_NZ_START(jcol));
for (i = U_NZ_START(jcol); i < U_NZ_END(jcol); i++ ){
irow = U_SUB(i);
rhs_work[irow] -= rhs_work[jcol] * Uval[i];
}
}
}
} /* for U-solve */
#if ( DEBUGlevel>=2 )
printf("After U-solve: x=\n");
print_soln(n, nrhs, Bmat);
#endif
/* Compute the final solution X <= Pc*X. */
for (i = 0, bptr = 0; i < nrhs; i++, bptr += ldb) {
rhs_work = &Bmat[bptr];
for (k = 0; k < n; k++) soln[k] = rhs_work[perm_c[k]];
for (k = 0; k < n; k++) rhs_work[k] = soln[k];
}
} else { /* Solve A'*X=B */
/* Permute right hand sides to form Pc'*B. */
for (i = 0, bptr = 0; i < nrhs; i++, bptr += ldb) {
rhs_work = &Bmat[bptr];
for (k = 0; k < n; k++) soln[perm_c[k]] = rhs_work[k];
for (k = 0; k < n; k++) rhs_work[k] = soln[k];
}
for (k = 0; k < nrhs; ++k) {
/* Multiply by inv(U'). */
sp_dtrsv("U", "T", "N", L, U, &Bmat[k*ldb], info);
/* Multiply by inv(L'). */
sp_dtrsv("L", "T", "U", L, U, &Bmat[k*ldb], info);
}
/* Compute the final solution X <= Pr'*X (=inv(Pr)*X) */
for (i = 0, bptr = 0; i < nrhs; i++, bptr += ldb) {
rhs_work = &Bmat[bptr];
for (k = 0; k < n; k++) soln[k] = rhs_work[perm_r[k]];
for (k = 0; k < n; k++) rhs_work[k] = soln[k];
}
} /* if-else trans */
Gstat->ops[TRISOLVE] = solve_ops;
SUPERLU_FREE(work);
SUPERLU_FREE(soln);
}
/*
* Diagnostic print of the solution vector
*/
void
print_soln(int n, int nrhs, double *soln)
{
register int i;
for (i = 0; i < n; i++)
printf("\t%d: %.10f\n", i, soln[i]);
}
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