XLPack 7.0
Python API Reference Manual
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◆ ssr_dusmv()

def ssr_dusmv ( uplo  ,
,
alpha  ,
val  ,
rowptr  ,
colind  ,
base  ,
,
incx  ,
beta  ,
,
incy   
)

y <- αAx + βy (Symmetric matrices) (CSR)

Purpose
This function performs the following matrix-vector operation for a symmetric sparse matrix A in CSR format.
y <- αAx + βy
where α and β are scalars, x and y are vectors. A is an n x n symmetric sparse matrix.

The order of elements in each row of input matrix A must be ascending order of column index. The triangular elements (not including diagonal elements) other than specified by uplo will be ignored.
Returns
info (int)
= 0: Successful exit.
= i < 0: The (-i)-th argument is invalid.
Parameters
[in]uploSpecifies whether the upper or lower triangular part of input matrix A is stored.
= 'U': Upper triangular part.
= 'L': Lower triangular part.
[in]nNumber of rows and columns of matrix A. (n >= 0) (If n = 0, returns without computation)
[in]alphaScalar α
[in]valNumpy ndarray (1-dimensional, float, nnz)
Values of nonzero elements of matrix A (where nnz is the number of nonzero elements).
[in]rowptrNumpy ndarray (1-dimensional, int32, m + 1)
Row pointers of matrix A.
[in]colindNumpy ndarray (1-dimensional, int32, nnz)
Column indices of matrix A (where nnz is the number of nonzero elements).
[in]baseIndexing of rowptr[] and colind[].
= 0: Zero-based (C style) indexing: Starting index is 0.
= 1: One-based (Fortran style) indexing: Starting index is 1.
[in]xNumpy ndarray (1-dimensional, float, 1 + (n - 1)*incx)
Vector x.
[in]incxStorage spacing between elements of x.
[in]betaScalar β.
[in,out]yNumpy ndarray (1-dimensional, float, 1 + (m - 1)*incy)
[in] Input vector y (If beta is supplied as zero, y needs not be set on input).
[out] Output vector. (= αAx + βy)
[in]incyStorage spacing between elements of y.