dla_geamv - vector product using a general matrix to calculate error bounds
SUBROUTINE DLA_GEAMV (TRANS, M, N, ALPHA, A, LDA, X, INCX, BETA, Y, INCY) DOUBLE PRECISION ALPHA, BETA INTEGER INCX, INCY, LDA, M, N, TRANS DOUBLE PRECISION A(LDA,*), X(*), Y(*) SUBROUTINE DLA_GEAMV_64 (TRANS, M, N, ALPHA, A, LDA, X, INCX, BETA, Y, INCY) DOUBLE PRECISION ALPHA, BETA INTEGER*8 INCX, INCY, LDA, M, N, TRANS DOUBLE PRECISION A(LDA,*), X(*), Y(*) F95 INTERFACE SUBROUTINE LA_GEAMV (TRANS, M, N, ALPHA, A, LDA, X, INCX, BETA, Y, INCY) INTEGER :: TRANS, M, N, LDA, INCX, INCY REAL(8), DIMENSION(:,:) :: A REAL(8), DIMENSION(:) :: X, Y REAL(8) :: ALPHA, BETA SUBROUTINE LA_GEAMV_64 (TRANS, M, N, ALPHA, A, LDA, X, INCX, BETA, Y, INCY) INTEGER(8) :: TRANS, M, N, LDA, INCX, INCY REAL(8), DIMENSION(:,:) :: A REAL(8), DIMENSION(:) :: X, Y REAL(8) :: ALPHA, BETA C INTERFACE #include <sunperf.h> void dla_geamv (int trans, int m, int n, double alpha, double *a, int lda, double *x, int incx, double beta, double *y, int incy); void dla_geamv_64 (long trans, long m, long n, double alpha, double *a, long lda, double *x, long incx, double beta, double *y, long incy);
Oracle Solaris Studio Performance Library dla_geamv(3P)
NAME
dla_geamv - compute a matrix-vector product using a general matrix to
calculate error bounds
SYNOPSIS
SUBROUTINE DLA_GEAMV (TRANS, M, N, ALPHA, A, LDA, X, INCX, BETA, Y,
INCY)
DOUBLE PRECISION ALPHA, BETA
INTEGER INCX, INCY, LDA, M, N, TRANS
DOUBLE PRECISION A(LDA,*), X(*), Y(*)
SUBROUTINE DLA_GEAMV_64 (TRANS, M, N, ALPHA, A, LDA, X, INCX, BETA, Y,
INCY)
DOUBLE PRECISION ALPHA, BETA
INTEGER*8 INCX, INCY, LDA, M, N, TRANS
DOUBLE PRECISION A(LDA,*), X(*), Y(*)
F95 INTERFACE
SUBROUTINE LA_GEAMV (TRANS, M, N, ALPHA, A, LDA, X, INCX, BETA, Y,
INCY)
INTEGER :: TRANS, M, N, LDA, INCX, INCY
REAL(8), DIMENSION(:,:) :: A
REAL(8), DIMENSION(:) :: X, Y
REAL(8) :: ALPHA, BETA
SUBROUTINE LA_GEAMV_64 (TRANS, M, N, ALPHA, A, LDA, X, INCX, BETA, Y,
INCY)
INTEGER(8) :: TRANS, M, N, LDA, INCX, INCY
REAL(8), DIMENSION(:,:) :: A
REAL(8), DIMENSION(:) :: X, Y
REAL(8) :: ALPHA, BETA
C INTERFACE
#include <sunperf.h>
void dla_geamv (int trans, int m, int n, double alpha, double *a, int
lda, double *x, int incx, double beta, double *y, int incy);
void dla_geamv_64 (long trans, long m, long n, double alpha, double *a,
long lda, double *x, long incx, double beta, double *y, long
incy);
PURPOSE
dla_geamv performs one of the matrix-vector operations
y := alpha*abs(A)*abs(x) + beta*abs(y),
or y := alpha*abs(A)**T*abs(x) + beta*abs(y),
where alpha and beta are scalars, x and y are vectors and A is an m by
n matrix.
This function is primarily used in calculating error bounds. To pro-
tect against underflow during evaluation, components in the resulting
vector are perturbed away from zero by (N+1) times the underflow
threshold. To prevent unnecessarily large errors for block-structure
embedded in general matrices, "symbolically" zero components are not
perturbed. A zero entry is considered "symbolic" if all multiplications
involved in computing that entry have at least one zero multiplicand.
ARGUMENTS
TRANS (input)
TRANS is INTEGER
On entry, TRANS specifies the operation to be performed as
follows:
BLAS_NO_TRANS y := alpha*abs(A)*abs(x) + beta*abs(y)
BLAS_TRANS y := alpha*abs(A**T)*abs(x) + beta*abs(y)
BLAS_CONJ_TRANS y := alpha*abs(A**T)*abs(x) + beta*abs(y)
Unchanged on exit.
M (input)
M is INTEGER
On entry, M specifies the number of rows of the matrix A.
M must be at least zero.
Unchanged on exit.
N (input)
N is INTEGER
On entry, N specifies the number of columns of the matrix A.
N must be at least zero.
Unchanged on exit.
ALPHA (input)
ALPHA is DOUBLE PRECISION
On entry, ALPHA specifies the scalar alpha.
Unchanged on exit.
A (input)
A is DOUBLE PRECISION 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 (input)
LDA is 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 (input)
X is DOUBLE PRECISION array, dimension
(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 (input)
INCX is INTEGER
On entry, INCX specifies the increment for the elements of X.
INCX must not be zero.
Unchanged on exit.
BETA (input)
BETA is DOUBLE PRECISION
On entry, BETA specifies the scalar beta. When BETA is sup-
plied as zero then Y need not be set on input.
Unchanged on exit.
Y (input/output)
Y is DOUBLE PRECISION
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)
INCY is INTEGER
On entry, INCY specifies the increment for the elements of Y.
INCY must not be zero.
Unchanged on exit.
Level 2 Blas routine.
7 Nov 2015 dla_geamv(3P)