MatQRFactor#

Performs in-place QR factorization of matrix.

Synopsis#

#include "petscmat.h" 
PetscErrorCode MatQRFactor(Mat mat, IS col, const MatFactorInfo *info)

Collective

Input Parameters#

  • mat - the matrix

  • col - column permutation

  • info - options for factorization, includes

          fill - expected fill as ratio of original fill.
          dtcol - pivot tolerance (0 no pivot, 1 full column pivoting)
                   Run with the option -info to determine an optimal value to use

Notes#

Most users should employ the KSP interface for linear solvers instead of working directly with matrix algebra routines such as this. See, e.g., KSPCreate().

This changes the state of the matrix to a factored matrix; it cannot be used for example with MatSetValues() unless one first calls MatSetUnfactored().

Developer Note#

The Fortran interface is not autogenerated as the interface definition cannot be generated correctly [due to MatFactorInfo]

See Also#

Matrices, Mat, Matrix Factorization, MatFactorInfo, MatGetFactor(), MatQRFactorSymbolic(), MatQRFactorNumeric(), MatLUFactor(), MatSetUnfactored()

Level#

developer

Location#

src/mat/interface/matrix.c

Implementations#

MatQRFactor_SeqDense() in src/mat/impls/dense/seq/dense.c

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