Intel® oneAPI Math Kernel Library Developer Reference - Fortran
Computes a matrix-vector product for complex vectors using a complex symmetric packed matrix.
call cspmv( uplo, n, alpha, ap, x, incx, beta, y, incy )
call zspmv( uplo, n, alpha, ap, x, incx, beta, y, incy )
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 in Chapter "BLAS and Sparse BLAS Routines").
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 .
INTEGER.
Specifies the order of the matrix a.
The value of n must be at least zero.
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.
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.
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.
INTEGER. Specifies the increment for the elements of x. The value of incx must not be zero.
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.
INTEGER. Specifies the increment for the elements of y. The value of incy must not be zero.
Overwritten by the updated vector y.