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Updated: June 2017
 
 

zla_geamv (3p)

Name

zla_geamv - vector product using a general matrix to calculate error bounds

Synopsis

SUBROUTINE ZLA_GEAMV (TRANS, M, N, ALPHA, A, LDA,  X,  INCX,  BETA,  Y,
INCY)


DOUBLE PRECISION ALPHA, BETA

INTEGER INCX, INCY, LDA, M, N

INTEGER TRANS

DOUBLE COMPLEX A(LDA,*), X(*)

DOUBLE PRECISION Y(*)


SUBROUTINE  ZLA_GEAMV_64 (TRANS, M, N, ALPHA, A, LDA, X, INCX, BETA, Y,
INCY)


DOUBLE PRECISION ALPHA, BETA

INTEGER*8 INCX, INCY, LDA, M, N

INTEGER*8 TRANS

DOUBLE COMPLEX A(LDA,*), X(*)

DOUBLE PRECISION 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(:) :: Y

COMPLEX(8), DIMENSION(:,:) :: A

COMPLEX(8), DIMENSION(:) :: X

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(:) :: Y

COMPLEX(8), DIMENSION(:,:) :: A

COMPLEX(8), DIMENSION(:) :: X

REAL(8) :: ALPHA, BETA


C INTERFACE
#include <sunperf.h>

void zla_geamv (int trans, int m, int n,  double  alpha,  doublecomplex
*a,  int lda, doublecomplex *x, int incx, double beta, double
*y, int incy);


void zla_geamv_64 (long trans, long m, long n, double alpha, doublecom-
plex  *a, long lda, doublecomplex *x, long incx, double beta,
double *y, long incy);

Description

Oracle Solaris Studio Performance Library                        zla_geamv(3P)



NAME
       zla_geamv  -  compute a matrix-vector product using a general matrix to
       calculate error bounds


SYNOPSIS
       SUBROUTINE ZLA_GEAMV (TRANS, M, N, ALPHA, A, LDA,  X,  INCX,  BETA,  Y,
                 INCY)


       DOUBLE PRECISION ALPHA, BETA

       INTEGER INCX, INCY, LDA, M, N

       INTEGER TRANS

       DOUBLE COMPLEX A(LDA,*), X(*)

       DOUBLE PRECISION Y(*)


       SUBROUTINE  ZLA_GEAMV_64 (TRANS, M, N, ALPHA, A, LDA, X, INCX, BETA, Y,
                 INCY)


       DOUBLE PRECISION ALPHA, BETA

       INTEGER*8 INCX, INCY, LDA, M, N

       INTEGER*8 TRANS

       DOUBLE COMPLEX A(LDA,*), X(*)

       DOUBLE PRECISION 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(:) :: Y

       COMPLEX(8), DIMENSION(:,:) :: A

       COMPLEX(8), DIMENSION(:) :: X

       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(:) :: Y

       COMPLEX(8), DIMENSION(:,:) :: A

       COMPLEX(8), DIMENSION(:) :: X

       REAL(8) :: ALPHA, BETA


   C INTERFACE
       #include <sunperf.h>

       void zla_geamv (int trans, int m, int n,  double  alpha,  doublecomplex
                 *a,  int lda, doublecomplex *x, int incx, double beta, double
                 *y, int incy);


       void zla_geamv_64 (long trans, long m, long n, double alpha, doublecom-
                 plex  *a, long lda, doublecomplex *x, long incx, double beta,
                 double *y, long incy);


PURPOSE
       zla_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 multiplica-
       tions involved in computing that entry have at least one zero multipli-
       cand.


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 COMPLEX*16 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 COMPLEX*16 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 (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, dimension
                 ( 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                     zla_geamv(3P)