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◆ csr_dussm()
| def csr_dussm |
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uplo |
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trans |
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diag |
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order |
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n |
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nrhs |
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val |
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rowptr |
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colind |
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base |
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x |
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Solution of AX = B or ATX = B (Triangular matrices) (CSR)
- Purpose
- This function solves one of the following systems of equations for a sparse matrix in CSR format. where A is an n x n upper or lower sparse triangular matrix, and B and X are n x nrhs dense matrices.
- Returns
- info (int)
= 0: Successful exit.
= i < 0: The (-i)-th argument is invalid.
= i > 0: The matrix is singular (i-th diagonal element is zero).
- Parameters
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| [in] | uplo | Specifies whether the matrix is an upper or lower triangular matrix as follows:
= 'U': A is an upper triangular matrix.
= 'L': A is an lower triangular matrix.
The other triangular elements (not including diagonal elements) are ignored. |
| [in] | trans | Specifies the equation to be solved as follows:
= 'N': A*X = B.
= 'T' or 'C': A^T*X = B. |
| [in] | diag | Specifies whether or not A is assumed to be unit triangular.
= 'N': A is not assumed to be unit triangular.
= 'U': A is assumed to be unit triangular. (diagonal elements are assumed to be ones. val[]s at diagonal element positions (if exist) are ignored.) |
| [in] | order | Storage order of x[].
= 'C': Column major.
= 'R': Row major. |
| [in] | n | Number of rows and columns of matrix A. (n >= 0) (If n = 0, returns without computation) |
| [in] | nrhs | Number of columns of matrices B and C. (nrhs >= 0) (if nrhs = 0, returns without computation) |
| [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, n + 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] | ldx | Leading dimension of two dimensional array x[]. (ldx >= n) |
| [in,out] | x | Numpy ndarray (2-dimensional, float, n x nrhs)
[in] Right-hand side matrix B.
[out] Solution matrix X. |
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