NAME¶
CGEMV - perform one of the matrix-vector operations y := alpha*A*x + beta*y, or
y := alpha*A'*x + beta*y, or y := alpha*conjg( A' )*x + beta*y,
SYNOPSIS¶
- SUBROUTINE CGEMV
- ( TRANS, M, N, ALPHA, A, LDA, X, INCX, BETA, Y, INCY )
COMPLEX ALPHA, BETA INTEGER INCX, INCY, LDA, M, N CHARACTER*1 TRANS COMPLEX A(
LDA, * ), X( * ), Y( * )
PURPOSE¶
CGEMV performs one of the matrix-vector operations
where alpha and beta are scalars, x and y are vectors and A is an m by n matrix.
PARAMETERS¶
- TRANS - CHARACTER*1.
- 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*conjg( A' )*x + beta*y.
Unchanged on exit.
- M - INTEGER.
- On entry, M specifies the number of rows of the matrix A. M must be at
least zero. Unchanged on exit.
- N - INTEGER.
- On entry, N specifies the number of columns of the matrix A. N must be at
least zero. Unchanged on exit.
- ALPHA - COMPLEX .
- On entry, ALPHA specifies the scalar alpha. Unchanged on exit.
- A - COMPLEX array of DIMENSION ( LDA, n ).
- Before entry, the leading m by n part of the array A must contain the
matrix of coefficients. Unchanged on exit.
- LDA - INTEGER.
- On entry, LDA specifies the first dimension of A as declared in the
calling (sub) program. LDA must be at least max( 1, m ). Unchanged on
exit.
- X - COMPLEX 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. Unchanged on exit.
- INCX - INTEGER.
- On entry, INCX specifies the increment for the elements of X. INCX must
not be zero. Unchanged on exit.
- BETA - COMPLEX .
- On entry, BETA specifies the scalar beta. When BETA is supplied as zero
then Y need not be set on input. Unchanged on exit.
- Y - COMPLEX 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 - INTEGER.
- On entry, INCY specifies the increment for the elements of Y. INCY must
not be zero. Unchanged on exit.
Level 2 Blas routine.
-- Written on 22-October-1986. Jack Dongarra, Argonne National Lab. Jeremy
Du Croz, Nag Central Office. Sven Hammarling, Nag Central Office. Richard
Hanson, Sandia National Labs.