/*! @file ssp_blas2.c
* \brief Sparse BLAS 2, using some dense BLAS 2 operations
*
* <pre>
* -- SuperLU routine (version 3.0) --
* Univ. of California Berkeley, Xerox Palo Alto Research Center,
* and Lawrence Berkeley National Lab.
* October 15, 2003
* </pre>
*/
/*
* File name: ssp_blas2.c
* Purpose: Sparse BLAS 2, using some dense BLAS 2 operations.
*/
#include "slu_sdefs.h"
/*
* Function prototypes
*/
void susolve(int, int, float*, float*);
void slsolve(int, int, float*, float*);
void smatvec(int, int, int, float*, float*, float*);
/*! \brief Solves one of the systems of equations A*x = b, or A'*x = b
*
* <pre>
* Purpose
* =======
*
* sp_strsv() solves one of the systems of equations
* A*x = b, or A'*x = b,
* where b and x are n element vectors and A is a sparse unit , or
* non-unit, upper or lower triangular matrix.
* No test for singularity or near-singularity is included in this
* routine. Such tests must be performed before calling this routine.
*
* Parameters
* ==========
*
* uplo - (input) char*
* On entry, uplo specifies whether the matrix is an upper or
* lower triangular matrix as follows:
* uplo = 'U' or 'u' A is an upper triangular matrix.
* uplo = 'L' or 'l' A is a lower triangular matrix.
*
* trans - (input) char*
* On entry, trans specifies the equations to be solved as
* follows:
* trans = 'N' or 'n' A*x = b.
* trans = 'T' or 't' A'*x = b.
* trans = 'C' or 'c' A'*x = b.
*
* diag - (input) char*
* On entry, diag specifies whether or not A is unit
* triangular as follows:
* diag = 'U' or 'u' A is assumed to be unit triangular.
* diag = 'N' or 'n' A is not assumed to be unit
* triangular.
*
* L - (input) SuperMatrix*
* The factor L from the factorization Pr*A*Pc=L*U. Use
* compressed row subscripts storage for supernodes,
* i.e., L has types: Stype = SC, Dtype = SLU_S, Mtype = TRLU.
*
* U - (input) SuperMatrix*
* The factor U from the factorization Pr*A*Pc=L*U.
* U has types: Stype = NC, Dtype = SLU_S, Mtype = TRU.
*
* x - (input/output) float*
* Before entry, the incremented array X must contain the n
* element right-hand side vector b. On exit, X is overwritten
* with the solution vector x.
*
* info - (output) int*
* If *info = -i, the i-th argument had an illegal value.
* </pre>
*/
int
sp_strsv(char *uplo, char *trans, char *diag, SuperMatrix *L,
SuperMatrix *U, float *x, SuperLUStat_t *stat, int *info)
{
#ifdef _CRAY
_fcd ftcs1 = _cptofcd("L", strlen("L")),
ftcs2 = _cptofcd("N", strlen("N")),
ftcs3 = _cptofcd("U", strlen("U"));
#endif
SCformat *Lstore;
NCformat *Ustore;
float *Lval, *Uval;
int incx = 1, incy = 1;
float alpha = 1.0, beta = 1.0;
int nrow;
int fsupc, nsupr, nsupc, luptr, istart, irow;
int i, k, iptr, jcol;
float *work;
flops_t solve_ops;
/* Test the input parameters */
*info = 0;
if ( !lsame_(uplo,"L") && !lsame_(uplo, "U") ) *info = -1;
else if ( !lsame_(trans, "N") && !lsame_(trans, "T") &&
!lsame_(trans, "C")) *info = -2;
else if ( !lsame_(diag, "U") && !lsame_(diag, "N") ) *info = -3;
else if ( L->nrow != L->ncol || L->nrow < 0 ) *info = -4;
else if ( U->nrow != U->ncol || U->nrow < 0 ) *info = -5;
if ( *info ) {
i = -(*info);
xerbla_("sp_strsv", &i);
return 0;
}
Lstore = L->Store;
Lval = Lstore->nzval;
Ustore = U->Store;
Uval = Ustore->nzval;
solve_ops = 0;
if ( !(work = floatCalloc(L->nrow)) )
ABORT("Malloc fails for work in sp_strsv().");
if ( lsame_(trans, "N") ) { /* Form x := inv(A)*x. */
if ( lsame_(uplo, "L") ) {
/* Form x := inv(L)*x */
if ( L->nrow == 0 ) return 0; /* Quick return */
for (k = 0; k <= Lstore->nsuper; k++) {
fsupc = L_FST_SUPC(k);
istart = L_SUB_START(fsupc);
nsupr = L_SUB_START(fsupc+1) - istart;
nsupc = L_FST_SUPC(k+1) - fsupc;
luptr = L_NZ_START(fsupc);
nrow = nsupr - nsupc;
solve_ops += nsupc * (nsupc - 1);
solve_ops += 2 * nrow * nsupc;
if ( nsupc == 1 ) {
for (iptr=istart+1; iptr < L_SUB_START(fsupc+1); ++iptr) {
irow = L_SUB(iptr);
++luptr;
x[irow] -= x[fsupc] * Lval[luptr];
}
} else {
#ifdef USE_VENDOR_BLAS
#ifdef _CRAY
STRSV(ftcs1, ftcs2, ftcs3, &nsupc, &Lval[luptr], &nsupr,
&x[fsupc], &incx);
SGEMV(ftcs2, &nrow, &nsupc, &alpha, &Lval[luptr+nsupc],
&nsupr, &x[fsupc], &incx, &beta, &work[0], &incy);
#else
strsv_("L", "N", "U", &nsupc, &Lval[luptr], &nsupr,
&x[fsupc], &incx);
sgemv_("N", &nrow, &nsupc, &alpha, &Lval[luptr+nsupc],
&nsupr, &x[fsupc], &incx, &beta, &work[0], &incy);
#endif
#else
slsolve ( nsupr, nsupc, &Lval[luptr], &x[fsupc]);
smatvec ( nsupr, nsupr-nsupc, nsupc, &Lval[luptr+nsupc],
&x[fsupc], &work[0] );
#endif
iptr = istart + nsupc;
for (i = 0; i < nrow; ++i, ++iptr) {
irow = L_SUB(iptr);
x[irow] -= work[i]; /* Scatter */
work[i] = 0.0;
}
}
} /* for k ... */
} else {
/* Form x := inv(U)*x */
if ( U->nrow == 0 ) return 0; /* Quick return */
for (k = Lstore->nsuper; k >= 0; k--) {
fsupc = L_FST_SUPC(k);
nsupr = L_SUB_START(fsupc+1) - L_SUB_START(fsupc);
nsupc = L_FST_SUPC(k+1) - fsupc;
luptr = L_NZ_START(fsupc);
solve_ops += nsupc * (nsupc + 1);
if ( nsupc == 1 ) {
x[fsupc] /= Lval[luptr];
for (i = U_NZ_START(fsupc); i < U_NZ_START(fsupc+1); ++i) {
irow = U_SUB(i);
x[irow] -= x[fsupc] * Uval[i];
}
} else {
#ifdef USE_VENDOR_BLAS
#ifdef _CRAY
STRSV(ftcs3, ftcs2, ftcs2, &nsupc, &Lval[luptr], &nsupr,
&x[fsupc], &incx);
#else
strsv_("U", "N", "N", &nsupc, &Lval[luptr], &nsupr,
&x[fsupc], &incx);
#endif
#else
susolve ( nsupr, nsupc, &Lval[luptr], &x[fsupc] );
#endif
for (jcol = fsupc; jcol < L_FST_SUPC(k+1); jcol++) {
solve_ops += 2*(U_NZ_START(jcol+1) - U_NZ_START(jcol));
for (i = U_NZ_START(jcol); i < U_NZ_START(jcol+1);
i++) {
irow = U_SUB(i);
x[irow] -= x[jcol] * Uval[i];
}
}
}
} /* for k ... */
}
} else { /* Form x := inv(A')*x */
if ( lsame_(uplo, "L") ) {
/* Form x := inv(L')*x */
if ( L->nrow == 0 ) return 0; /* Quick return */
for (k = Lstore->nsuper; k >= 0; --k) {
fsupc = L_FST_SUPC(k);
istart = L_SUB_START(fsupc);
nsupr = L_SUB_START(fsupc+1) - istart;
nsupc = L_FST_SUPC(k+1) - fsupc;
luptr = L_NZ_START(fsupc);
solve_ops += 2 * (nsupr - nsupc) * nsupc;
for (jcol = fsupc; jcol < L_FST_SUPC(k+1); jcol++) {
iptr = istart + nsupc;
for (i = L_NZ_START(jcol) + nsupc;
i < L_NZ_START(jcol+1); i++) {
irow = L_SUB(iptr);
x[jcol] -= x[irow] * Lval[i];
iptr++;
}
}
if ( nsupc > 1 ) {
solve_ops += nsupc * (nsupc - 1);
#ifdef _CRAY
ftcs1 = _cptofcd("L", strlen("L"));
ftcs2 = _cptofcd("T", strlen("T"));
ftcs3 = _cptofcd("U", strlen("U"));
STRSV(ftcs1, ftcs2, ftcs3, &nsupc, &Lval[luptr], &nsupr,
&x[fsupc], &incx);
#else
strsv_("L", "T", "U", &nsupc, &Lval[luptr], &nsupr,
&x[fsupc], &incx);
#endif
}
}
} else {
/* Form x := inv(U')*x */
if ( U->nrow == 0 ) return 0; /* Quick return */
for (k = 0; k <= Lstore->nsuper; k++) {
fsupc = L_FST_SUPC(k);
nsupr = L_SUB_START(fsupc+1) - L_SUB_START(fsupc);
nsupc = L_FST_SUPC(k+1) - fsupc;
luptr = L_NZ_START(fsupc);
for (jcol = fsupc; jcol < L_FST_SUPC(k+1); jcol++) {
solve_ops += 2*(U_NZ_START(jcol+1) - U_NZ_START(jcol));
for (i = U_NZ_START(jcol); i < U_NZ_START(jcol+1); i++) {
irow = U_SUB(i);
x[jcol] -= x[irow] * Uval[i];
}
}
solve_ops += nsupc * (nsupc + 1);
if ( nsupc == 1 ) {
x[fsupc] /= Lval[luptr];
} else {
#ifdef _CRAY
ftcs1 = _cptofcd("U", strlen("U"));
ftcs2 = _cptofcd("T", strlen("T"));
ftcs3 = _cptofcd("N", strlen("N"));
STRSV( ftcs1, ftcs2, ftcs3, &nsupc, &Lval[luptr], &nsupr,
&x[fsupc], &incx);
#else
strsv_("U", "T", "N", &nsupc, &Lval[luptr], &nsupr,
&x[fsupc], &incx);
#endif
}
} /* for k ... */
}
}
stat->ops[SOLVE] += solve_ops;
SUPERLU_FREE(work);
return 0;
}
/*! \brief Performs one of the matrix-vector operations y := alpha*A*x + beta*y, or y := alpha*A'*x + beta*y,
*
* <pre>
* Purpose
* =======
*
* sp_sgemv() performs one of the matrix-vector operations
* y := alpha*A*x + beta*y, or y := alpha*A'*x + beta*y,
* where alpha and beta are scalars, x and y are vectors and A is a
* sparse A->nrow by A->ncol matrix.
*
* Parameters
* ==========
*
* TRANS - (input) char*
* On entry, TRANS specifies the operation to be performed as
* follows:
* TRANS = 'N' or 'n' y := alpha*A*x + beta*y.
* TRANS = 'T' or 't' y := alpha*A'*x + beta*y.
* TRANS = 'C' or 'c' y := alpha*A'*x + beta*y.
*
* ALPHA - (input) float
* On entry, ALPHA specifies the scalar alpha.
*
* A - (input) SuperMatrix*
* Matrix A with a sparse format, of dimension (A->nrow, A->ncol).
* Currently, the type of A can be:
* Stype = NC or NCP; Dtype = SLU_S; Mtype = GE.
* In the future, more general A can be handled.
*
* X - (input) float*, array of DIMENSION at least
* ( 1 + ( n - 1 )*abs( INCX ) ) when TRANS = 'N' or 'n'
* and at least
* ( 1 + ( m - 1 )*abs( INCX ) ) otherwise.
* Before entry, the incremented array X must contain the
* vector x.
*
* INCX - (input) int
* On entry, INCX specifies the increment for the elements of
* X. INCX must not be zero.
*
* BETA - (input) float
* On entry, BETA specifies the scalar beta. When BETA is
* supplied as zero then Y need not be set on input.
*
* Y - (output) float*, array of DIMENSION at least
* ( 1 + ( m - 1 )*abs( INCY ) ) when TRANS = 'N' or 'n'
* and at least
* ( 1 + ( n - 1 )*abs( INCY ) ) otherwise.
* Before entry with BETA non-zero, the incremented array Y
* must contain the vector y. On exit, Y is overwritten by the
* updated vector y.
*
* INCY - (input) int
* On entry, INCY specifies the increment for the elements of
* Y. INCY must not be zero.
*
* ==== Sparse Level 2 Blas routine.
* </pre>
*/
int
sp_sgemv(char *trans, float alpha, SuperMatrix *A, float *x,
int incx, float beta, float *y, int incy)
{
/* Local variables */
NCformat *Astore;
float *Aval;
int info;
float temp;
int lenx, leny, i, j, irow;
int iy, jx, jy, kx, ky;
int notran;
notran = lsame_(trans, "N");
Astore = A->Store;
Aval = Astore->nzval;
/* Test the input parameters */
info = 0;
if ( !notran && !lsame_(trans, "T") && !lsame_(trans, "C")) info = 1;
else if ( A->nrow < 0 || A->ncol < 0 ) info = 3;
else if (incx == 0) info = 5;
else if (incy == 0) info = 8;
if (info != 0) {
xerbla_("sp_sgemv ", &info);
return 0;
}
/* Quick return if possible. */
if (A->nrow == 0 || A->ncol == 0 || (alpha == 0. && beta == 1.))
return 0;
/* Set LENX and LENY, the lengths of the vectors x and y, and set
up the start points in X and Y. */
if (lsame_(trans, "N")) {
lenx = A->ncol;
leny = A->nrow;
} else {
lenx = A->nrow;
leny = A->ncol;
}
if (incx > 0) kx = 0;
else kx = - (lenx - 1) * incx;
if (incy > 0) ky = 0;
else ky = - (leny - 1) * incy;
/* Start the operations. In this version the elements of A are
accessed sequentially with one pass through A. */
/* First form y := beta*y. */
if (beta != 1.) {
if (incy == 1) {
if (beta == 0.)
for (i = 0; i < leny; ++i) y[i] = 0.;
else
for (i = 0; i < leny; ++i) y[i] = beta * y[i];
} else {
iy = ky;
if (beta == 0.)
for (i = 0; i < leny; ++i) {
y[iy] = 0.;
iy += incy;
}
else
for (i = 0; i < leny; ++i) {
y[iy] = beta * y[iy];
iy += incy;
}
}
}
if (alpha == 0.) return 0;
if ( notran ) {
/* Form y := alpha*A*x + y. */
jx = kx;
if (incy == 1) {
for (j = 0; j < A->ncol; ++j) {
if (x[jx] != 0.) {
temp = alpha * x[jx];
for (i = Astore->colptr[j]; i < Astore->colptr[j+1]; ++i) {
irow = Astore->rowind[i];
y[irow] += temp * Aval[i];
}
}
jx += incx;
}
} else {
ABORT("Not implemented.");
}
} else {
/* Form y := alpha*A'*x + y. */
jy = ky;
if (incx == 1) {
for (j = 0; j < A->ncol; ++j) {
temp = 0.;
for (i = Astore->colptr[j]; i < Astore->colptr[j+1]; ++i) {
irow = Astore->rowind[i];
temp += Aval[i] * x[irow];
}
y[jy] += alpha * temp;
jy += incy;
}
} else {
ABORT("Not implemented.");
}
}
return 0;
} /* sp_sgemv */