chpmv.f (3) - Linux Manuals

NAME

chpmv.f -

SYNOPSIS


Functions/Subroutines


subroutine chpmv (UPLO, N, ALPHA, AP, X, INCX, BETA, Y, INCY)
CHPMV

Function/Subroutine Documentation

subroutine chpmv (characterUPLO, integerN, complexALPHA, complex, dimension(*)AP, complex, dimension(*)X, integerINCX, complexBETA, complex, dimension(*)Y, integerINCY)

CHPMV Purpose:

 CHPMV  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 hermitian matrix, supplied in packed form.


 

Parameters:

UPLO

          UPLO is CHARACTER*1
           On entry, UPLO specifies whether the upper or lower
           triangular part of the matrix A is supplied in the packed
           array AP as follows:

              UPLO = 'U' or 'u'   The upper triangular part of A is
                                  supplied in AP.

              UPLO = 'L' or 'l'   The lower triangular part of A is
                                  supplied in AP.


N

          N is INTEGER
           On entry, N specifies the order of the matrix A.
           N must be at least zero.


ALPHA

          ALPHA is COMPLEX
           On entry, ALPHA specifies the scalar alpha.


AP

          AP is COMPLEX array of DIMENSION at least
           ( ( n*( n + 1 ) )/2 ).
           Before entry with UPLO = 'U' or 'u', the array AP must
           contain the upper triangular part of the hermitian matrix
           packed sequentially, column by column, so that AP( 1 )
           contains a( 1, 1 ), AP( 2 ) and AP( 3 ) contain a( 1, 2 )
           and a( 2, 2 ) respectively, and so on.
           Before entry with UPLO = 'L' or 'l', the array AP must
           contain the lower triangular part of the hermitian matrix
           packed sequentially, column by column, so that AP( 1 )
           contains a( 1, 1 ), AP( 2 ) and AP( 3 ) contain a( 2, 1 )
           and a( 3, 1 ) respectively, and so on.
           Note that the imaginary parts of the diagonal elements need
           not be set and are assumed to be zero.


X

          X is COMPLEX array of dimension at least
           ( 1 + ( n - 1 )*abs( INCX ) ).
           Before entry, the incremented array X must contain the n
           element vector x.


INCX

          INCX is INTEGER
           On entry, INCX specifies the increment for the elements of
           X. INCX must not be zero.


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.


Y

          Y is COMPLEX array of 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.


 

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

November 2011

Further Details:

  Level 2 Blas routine.
  The vector and matrix arguments are not referenced when N = 0, or M = 0

  -- 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.


 

Definition at line 150 of file chpmv.f.

Author

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