ZHPMV
Purpose
ZHPMV 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.
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.
Arguments
| UPLO |
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. Unchanged on exit. |
| N |
INTEGER.
On entry, N specifies the order of the matrix A.
N must be at least zero. Unchanged on exit. |
| ALPHA |
COMPLEX*16 .
On entry, ALPHA specifies the scalar alpha.
Unchanged on exit. |
| AP |
COMPLEX*16 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. Unchanged on exit. |
| X |
COMPLEX*16 array of 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 |
INTEGER.
On entry, INCX specifies the increment for the elements of
X. INCX must not be zero. Unchanged on exit. |
| BETA |
COMPLEX*16 .
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*16 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 |
INTEGER.
On entry, INCY specifies the increment for the elements of
Y. INCY must not be zero. Unchanged on exit. |
Further Details
Level 2 Blas routine.
The vector and matrix arguments are not referenced when N = 0, or M = 0
Jack Dongarra, Argonne National Lab.
Jeremy Du Croz, Nag Central Office.
Sven Hammarling, Nag Central Office.
Richard Hanson, Sandia National Labs.
The vector and matrix arguments are not referenced when N = 0, or M = 0
Jack Dongarra, Argonne National Lab.
Jeremy Du Croz, Nag Central Office.
Sven Hammarling, Nag Central Office.
Richard Hanson, Sandia National Labs.