SRC/dsp_blas2.c File Reference

Sparse BLAS 2, using some dense BLAS 2 operations. More...

#include "superlu_ddefs.h"

Functions/Subroutines

void dusolve (int, int, double *, double *)
void dlsolve (int, int, double *, double *)
void dmatvec (int, int, int, double *, double *, double *)
int sp_dtrsv_dist (char *uplo, char *trans, char *diag, SuperMatrix *L, SuperMatrix *U, double *x, int *info)
int sp_dgemv_dist (char *trans, double alpha, SuperMatrix *A, double *x, int incx, double beta, double *y, int incy)


Detailed Description

 -- Distributed SuperLU routine (version 1.0) --
 Lawrence Berkeley National Lab, Univ. of California Berkeley.
 September 1, 1999
 

Function Documentation

void dlsolve ( int  ldm,
int  ncol,
double *  M,
double *  rhs 
)

 Solves a dense UNIT lower triangular system. The unit lower 
 triangular matrix is stored in a 2D array M(1:nrow,1:ncol). 
 The solution will be returned in the rhs vector.
 

void dmatvec ( int  ldm,
int  nrow,
int  ncol,
double *  M,
double *  vec,
double *  Mxvec 
)

 Performs a dense matrix-vector multiply: Mxvec = Mxvec + M * vec.
 The input matrix is M(1:nrow,1:ncol); The product is returned in Mxvec[].
 

void dusolve ( int  ldm,
int  ncol,
double *  M,
double *  rhs 
)

 Solves a dense upper triangular system. The upper triangular matrix is
 stored in a 2-dim array M(1:ldm,1:ncol). The solution will be returned
 in the rhs vector.
 

int sp_dgemv_dist ( char *  trans,
double  alpha,
SuperMatrix A,
double *  x,
int  incx,
double  beta,
double *  y,
int  incy 
)

  Purpose   
    =======

    sp_dgemv_dist()  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) double
             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 = SLU_NC or SLU_NCP; Dtype = SLU_D; Mtype = SLU_GE. 
             In the future, more general A can be handled.

    X      - (input) double*, 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) double
             On entry, BETA specifies the scalar beta. When BETA is   
             supplied as zero then Y need not be set on input.

    Y      - (output) double*,  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.   

int sp_dtrsv_dist ( char *  uplo,
char *  trans,
char *  diag,
SuperMatrix L,
SuperMatrix U,
double *  x,
int *  info 
)

   Purpose
   =======

   sp_dtrsv_dist() 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 = SLU_SC, Dtype = SLU_D, Mtype = SLU_TRLU.

   U       - (input) SuperMatrix*
	        The factor U from the factorization Pr*A*Pc=L*U.
	        U has types: Stype = SLU_NC, Dtype = SLU_D, Mtype = SLU_TRU.

   x       - (input/output) double*
             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.
 


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