?symv

Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

Download PDF

ID 766686

Date 10/15/2026

Version

Public

?symv

Computes a matrix-vector product for a complex symmetric matrix.

Syntax

call csymv(uplo, n, alpha, a, lda, x, incx, beta, y, incy)
call zsymv(uplo, n, alpha, a, lda, x, incx, beta, y, incy)

Include Files

mkl.fi

Description

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 (Computes a matrix-vector product for a symmetric matrix.) in Chapter “BLAS and Sparse BLAS Routines” ).

Input Parameters

uplo: 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.
n: INTEGER . Specifies the order of the matrix a . The value of n must be at least zero.
alpha , beta: 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.
a: 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.
lda: 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) .
x: 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 .
incx: INTEGER . Specifies the increment for the elements of x . The value of incx must not be zero.
y: 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 .
incy: INTEGER . Specifies the increment for the elements of y . The value of incy must not be zero.

Output Parameters

y: Overwritten by the updated vector y .

Select Your Language

Using Intel.com Search

Quick Links

Recent Searches

Advanced Search

Only search in

Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

?symv

Syntax

Include Files

Description

Input Parameters

Output Parameters