?spmv

Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

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ID 766686

Date 4/28/2026

Version

Public

?spmv

Computes a matrix-vector product for complex vectors using a complex symmetric packed matrix.

Syntax

call cspmv ( uplo , n , alpha , ap , x , incx , beta , y , incy )

call zspmv ( uplo , n , alpha , ap , x , incx , beta , y , incy )

Include Files

mkl.fi

Description

cspmv zspmv

The ?spmv routines perform a 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 complex symmetric matrix, supplied in packed form.

These routines have their real equivalents in BLAS (see ?spmv (Computes a matrix-vector product with a symmetric packed matrix.) in Chapter “BLAS and Sparse BLAS Routines” ).

Input Parameters

uplo: CHARACTER*1 . Specifies whether the upper or lower triangular part of the matrix a is supplied in the packed array ap . If uplo = 'U' or ‘u’ , the upper triangular part of the matrix a is supplied in the array ap . If uplo = 'L' or ‘l’ , the lower triangular part of the matrix a is supplied in the array ap .
n: INTEGER . Specifies the order of the matrix a . The value of n must be at least zero.
alpha , beta: COMPLEX for cspmv DOUBLE COMPLEX for zspmv Specify complex scalars alpha and beta . When beta is supplied as zero, then y need not be set on input.
ap: COMPLEX for cspmv DOUBLE COMPLEX for zspmv 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.
x: COMPLEX for cspmv DOUBLE COMPLEX for zspmv 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 cspmv DOUBLE COMPLEX for zspmv 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

?spmv

Syntax

Include Files

Description

Input Parameters

Output Parameters