F11MKF computes a matrix-matrix or transposed matrix-matrix product involving a real, square, sparse nonsymmetric matrix stored in compressed column (Harwell–Boeing) format.
SUBROUTINE F11MKF ( |
TRANS, N, M, ALPHA, ICOLZP, IROWIX, A, B, LDB, BETA, C, LDC, IFAIL) |
INTEGER |
N, M, ICOLZP(*), IROWIX(*), LDB, LDC, IFAIL |
REAL (KIND=nag_wp) |
ALPHA, A(*), B(LDB,*), BETA, C(LDC,*) |
CHARACTER(1) |
TRANS |
|
F11MKF computes either the matrix-matrix product
, or the transposed matrix-matrix product
, according to the value of the parameter
TRANS, where
is a real
by
sparse nonsymmetric matrix, of arbitrary sparsity pattern with
nonzero elements,
and
are
by
real dense matrices. The matrix
is stored in compressed column (Harwell–Boeing) storage format. The array
A stores all nonzero elements of
, while arrays
ICOLZP and
IROWIX store the compressed column indices and row indices of
respectively.
None.
If on entry
or
, explanatory error messages are output on the current error message unit (as defined by
X04AAF).
Not applicable.
F11MKF is threaded by NAG for parallel execution in multithreaded implementations of the NAG Library.
Please consult the
X06 Chapter Introduction for information on how to control and interrogate the OpenMP environment used within this routine. Please also consult the
Users' Note for your implementation for any additional implementation-specific information.
None.
This example reads in a sparse matrix
and a dense matrix
. It then calls F11MKF to compute the matrix-matrix product
and the transposed matrix-matrix product
, where