?symv

Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

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ID 766686

Date 4/28/2026

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

csymv zsymv

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 .

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Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

?symv

Syntax

Include Files

Description

Input Parameters

Output Parameters