ZSPMV(1) | LAPACK auxiliary routine (version 3.2) | ZSPMV(1) |
NAME¶
ZSPMV - performs the matrix-vector operation y := alpha*A*x + beta*y,
SYNOPSIS¶
- SUBROUTINE ZSPMV(
- UPLO, N, ALPHA, AP, X, INCX, BETA, Y, INCY )
CHARACTER UPLO INTEGER INCX, INCY, N COMPLEX*16 ALPHA, BETA COMPLEX*16 AP( * ), X( * ), Y( * )
PURPOSE¶
ZSPMV performs the matrix-vector operation where alpha and beta are scalars, x and y are n element vectors and A is an n by n symmetric matrix, supplied in packed form.
ARGUMENTS¶
- UPLO (input) 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 (input) INTEGER
- On entry, N specifies the order of the matrix A. N must be at least zero. Unchanged on exit.
- ALPHA (input) COMPLEX*16
- On entry, ALPHA specifies the scalar alpha. Unchanged on exit.
- AP (input) COMPLEX*16 array, 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 symmetric 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 symmetric 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. Unchanged on exit.
- X (input) COMPLEX*16 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 (input) INTEGER
- On entry, INCX specifies the increment for the elements of X. INCX must not be zero. Unchanged on exit.
- BETA (input) 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 (input/output) COMPLEX*16 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 (input) INTEGER
- On entry, INCY specifies the increment for the elements of Y. INCY must not be zero. Unchanged on exit.
November 2008 | LAPACK auxiliary routine (version 3.2) |