Intel® oneAPI Math Kernel Library Developer Reference - Fortran
Computes a matrix-vector product for a complex symmetric matrix.
call csymv( uplo, n, alpha, a, lda, x, incx, beta, y, incy )
call zsymv( uplo, n, alpha, a, lda, x, incx, beta, y, incy )
The routine performs the matrix-vector operation defined as
y := alpha*a*x + beta*y,
where:
alpha and beta are complex scalars
x and y are n-element complex vectors
a is an n-by-n symmetric complex matrix.
These routines have their real equivalents in BLAS (see ?symv in Chapter "BLAS and Sparse BLAS Routines").
CHARACTER*1. Specifies whether the upper or lower triangular part of the array a is used:
If uplo = 'U' or 'u', then the upper triangular part of the array a is used.
If uplo = 'L' or 'l', then the lower triangular part of the array a is used.
INTEGER. Specifies the order of the matrix a. The value of n must be at least zero.
COMPLEX for csymv
DOUBLE COMPLEX for zsymv
Specify the scalars alpha and beta. When beta is supplied as zero, then y need not be set on input.
COMPLEX for csymv
DOUBLE COMPLEX for zsymv
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.
INTEGER. Specifies the leading dimension of A as declared in the calling (sub)program. The value of lda must be at least max(1,n).
COMPLEX for csymv
DOUBLE COMPLEX for zsymv
Array, DIMENSION at least (1 + (n - 1)*abs(incx)). Before entry, the incremented array x must contain the n-element vector x.
INTEGER. Specifies the increment for the elements of x. The value of incx must not be zero.
COMPLEX for csymv
DOUBLE COMPLEX for zsymv
Array, DIMENSION at least (1 + (n - 1)*abs(incy)). Before entry, the incremented array y must contain the n-element vector y.
INTEGER. Specifies the increment for the elements of y. The value of incy must not be zero.
Overwritten by the updated vector y.