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  4. csymv(3)

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csymv.f(3) LAPACK csymv.f(3)

NAME

csymv.f

SYNOPSIS

Functions/Subroutines


subroutine csymv (UPLO, N, ALPHA, A, LDA, X, INCX, BETA, Y, INCY)
CSYMV computes a matrix-vector product for a complex symmetric matrix.

Function/Subroutine Documentation

subroutine csymv (character UPLO, integer N, complex ALPHA, complex, dimension( lda, * ) A, integer LDA, complex, dimension( * ) X, integer INCX, complex BETA, complex, dimension( * ) Y, integer INCY)

CSYMV computes a matrix-vector product for a complex symmetric matrix.

Purpose: 



 CSYMV  performs the matrix-vector  operation


    y := alpha*A*x + beta*y,


 where alpha and beta are scalars, x and y are n element vectors and


 A is an n by n symmetric matrix.

Parameters:

UPLO 



          UPLO is CHARACTER*1


           On entry, UPLO specifies whether the upper or lower


           triangular part of the array A is to be referenced as


           follows:


              UPLO = 'U' or 'u'   Only the upper triangular part of A


                                  is to be referenced.


              UPLO = 'L' or 'l'   Only the lower triangular part of A


                                  is to be referenced.


           Unchanged on exit.

N



          N is INTEGER


           On entry, N specifies the order of the matrix A.


           N must be at least zero.


           Unchanged on exit.

ALPHA



          ALPHA is COMPLEX


           On entry, ALPHA specifies the scalar alpha.


           Unchanged on exit.

A



          A is COMPLEX array, dimension ( LDA, N )


           Before entry, with  UPLO = 'U' or 'u', the leading n by n


           upper triangular part of the array A must contain the upper


           triangular part of the symmetric matrix and the strictly


           lower triangular part of A is not referenced.


           Before entry, with UPLO = 'L' or 'l', the leading n by n


           lower triangular part of the array A must contain the lower


           triangular part of the symmetric matrix and the strictly


           upper triangular part of A is not referenced.


           Unchanged on exit.

LDA



          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, N ).


           Unchanged on exit.

X



          X is COMPLEX array, dimension at least


           ( 1 + ( N - 1 )*abs( INCX ) ).


           Before entry, the incremented array X must contain the N-


           element vector x.


           Unchanged on exit.

INCX



          INCX is INTEGER


           On entry, INCX specifies the increment for the elements of


           X. INCX must not be zero.


           Unchanged on exit.

BETA



          BETA is 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



          Y is COMPLEX array, dimension at least


           ( 1 + ( N - 1 )*abs( INCY ) ).


           Before entry, the incremented array Y must contain the n


           element vector y. On exit, Y is overwritten by the updated


           vector y.

INCY



          INCY is INTEGER


           On entry, INCY specifies the increment for the elements of


           Y. INCY must not be zero.


           Unchanged on exit.

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

December 2016

Definition at line 159 of file csymv.f.

Author

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