QR_MUMPS
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Functions/Subroutines | |
subroutine | dqrm_rowperm (graph, cperm, rperm, nvar, stair) |
This routine computes a row permutation that puts the input matrix into a staircase format. More... | |
subroutine dqrm_rowperm | ( | type(dqrm_spmat_type) | graph, |
integer, dimension(:) | cperm, | ||
integer, dimension(:) | rperm, | ||
integer, dimension(:) | nvar, | ||
integer, dimension(:) | stair | ||
) |
This routine computes a row permutation that puts the input matrix into a staircase format.
This subroutine computes a row permutation rperm such that A(rperm, cperm) is as much as possible upper triangular. The idea is to have someting like:
|x | |x | in this case stair would be: | x | stair=(/ 2, 5, 7, 7, 9 /) | x | | x | | xx | | xx | | x | | x |
[in] | graph | a qrm_spmat_type containing the matrix |
[in] | cperm | a column permutation |
[out] | rperm | the computed row permutation |
[in] | nvar | nvar(i) is the number of variables in the node whose principal variable is i |
[out] | stair | stair(i) is the number of rows in step i of the stair structure computed on the input graph |
Definition at line 69 of file dqrm_rowperm.F90.
Referenced by dqrm_analyse().