66 lines
2.2 KiB
Markdown
66 lines
2.2 KiB
Markdown
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# FactorizationPLUGeTridRaw
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Computes an LU factorization of a general (non-symmetric) tridiagonal N-by-N matrix A using elimination with partial pivoting and row interchanges. The factorization has the form
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A = P * L * U
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where P is a permutation matrix, L is lower triangular with unit diagonal elements, and U is upper triangular. LAPACK function [GTTRF](https://www.intel.com/content/www/us/en/docs/onemkl/developer-reference-fortran/2025-2/gttrf.html).
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Computing for type matrix<double>
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```
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bool matrix::FactorizationPLUGeTridRaw(
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matrix& AF, // factored matrix A
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long[]& ipiv // pivot indices array
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);
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```
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Computing for type matrix<float>
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```
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bool matrixf::FactorizationPLUGeTridRaw(
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matrixf& AF, // factored matrix A
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long[]& ipiv // pivot indices array
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);
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```
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Computing for type matrix<complex>
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```
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bool matrixc::FactorizationPLUGeTridRaw(
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matrixc& AF, // factored matrix A
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long[]& ipiv // pivot indices array
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);
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```
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Computing for type matrix<complexf>
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```
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bool matrixcf::FactorizationPLUGeTridRaw(
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matrixcf& AF, // factored matrix A
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long[]& ipiv // pivot indices array
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);
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```
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Parameters
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AF
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[out] Factored matrix A. The factors L and U from the factorization A = P*L*U; the unit diagonal elements of L are not stored.
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ipiv
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[out] Pivot indices array of size N; row i of the matrix A was interchanged with row ipiv[i].
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Return Value
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Return true if successful, otherwise false in case of an [error](/en/docs/constants/errorswarnings/errorcodes).
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Note
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Matrix AF and pivot indices array ipiv[] are raw output of the GTTRF function and can be used for further calculations with methods [PLUGeTridLinearEquationsSolution](/en/docs/matrix/openblas/factored_calculations/plugetridlinearequations) and [PLUGeTridCondNumReciprocal](/en/docs/matrix/openblas/factored_calculations/plugetridcondnumreciprocal).
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