ZSYMV(1) | LAPACK auxiliary routine (version 3.2) | ZSYMV(1) |
NAME¶
ZSYMV - performs the matrix-vector operation y := alpha*A*x + beta*y,
SYNOPSIS¶
- SUBROUTINE ZSYMV(
- UPLO, N, ALPHA, A, LDA, X, INCX, BETA, Y, INCY )
CHARACTER UPLO INTEGER INCX, INCY, LDA, N COMPLEX*16 ALPHA, BETA COMPLEX*16 A( LDA, * ), X( * ), Y( * )
PURPOSE¶
ZSYMV 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.
ARGUMENTS¶
- UPLO (input) 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 (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.
- A (input) COMPLEX*16 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 (input) 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 (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) |