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◆ csr_dusmv()
| def csr_dusmv |
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rowptr |
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colind |
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incx |
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y <- αAx + βy or y <- αATx + βy (CSR)
- Purpose
- This function performs one of the following matrix-vector operations for a sparse matrix in CSR format.
y <- αAx + βy or y <- αA^Tx + βy
where alpha and beta are scalars, x and y are vectors and A is an m x n sparse matrix.
- Returns
- info (int)
= 0: Successful exit.
= i < 0: The (-i)-th argument is invalid.
- Parameters
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| [in] | trans | Specifies the operation to be performed.
= 'N': y <- y <- αAx + βy.
= 'T' or 'C': y <- αA^Tx + βy. |
| [in] | m | Number of rows of matrix A. (m >= 0) (If m = 0, returns without computation) |
| [in] | n | Number of columns of matrix A. (n >= 0) (If n = 0, returns without computation) |
| [in] | alpha | Scalar α |
| [in] | val | Numpy ndarray (1-dimensional, float, nnz)
Values of nonzero elements of matrix A (where nnz is the number of nonzero elements). |
| [in] | rowptr | Numpy ndarray (1-dimensional, int32, m + 1)
Row pointers of matrix A. |
| [in] | colind | Numpy ndarray (1-dimensional, int32, nnz)
Column indices of matrix A (where nnz is the number of nonzero elements). |
| [in] | base | Indexing 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] | x | Numpy ndarray (1-dimensional, float, 1 + (n - 1)*incx (if trans = 'N'), 1 + (m - 1)*incx (if trans = 'T' or 'C'))
Vector x. |
| [in] | incx | Storage spacing between elements of x. |
| [in] | beta | Scalar β. |
| [in,out] | y | Numpy ndarray (1-dimensional, float, 1 + (m - 1)*incy (if trans = 'N'), 1 + (n - 1)*incy (if trans = 'T' or 'C'))
[in] Input vector y (If beta is supplied as zero, y needs not be set on input).
[out] Output vector. (= αAx + βy) |
| [in] | incy | Storage spacing between elements of y. |
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