SuperLU: SRC/zldperm.c File Reference

SuperLU 5.2.2

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zldperm.c File Reference

Finds a row permutation so that the matrix has large entries on the diagonal. More...

`#include "slu_zdefs.h"`
Include dependency graph for zldperm.c:

## Functions
int_t | mc64id_ (int_t *)
int_t | mc64ad_ (int_t *, int_t *, int_t *, int_t[], int_t[], double[], int_t *, int_t[], int_t *, int_t[], int_t *, double[], int_t[], int_t[])
int | zldperm (int_t job, int_t n, int_t nnz, int_t colptr[], int_t adjncy[], doublecomplex nzval[], int_t *perm, double u[], double v[])

## Detailed Description

Copyright (c) 2003, The Regents of the University of California, through Lawrence Berkeley National Laboratory (subject to receipt of any required approvals from U.S. Dept. of Energy)

All rights reserved.

The source code is distributed under BSD license, see the file License.txt at the top-level directory.

    – SuperLU routine (version 4.0) –
    Lawrence Berkeley National Laboratory.
    June 30, 2009

## Function Documentation

int_t mc64ad_ | ( | int_t * | ,
|  | int_t * | ,
|  | int_t * | ,
|  | int_t | [],
|  | int_t | [],
|  | double | [],
|  | int_t * | ,
|  | int_t | [],
|  | int_t * | ,
|  | int_t | [],
|  | int_t * | ,
|  | double | [],
|  | int_t | [],
|  | int_t | []
| ) |  |

int_t mc64id_ | ( | int_t * |  | ) |

int zldperm | ( | int_t | job,
|  | int_t | n,
|  | int_t | nnz,
|  | int_t | colptr[],
|  | int_t | adjncy[],
|  | doublecomplex | nzval[],
|  | int_t * | perm,
|  | double | u[],
|  | double | v[]
| ) |  |

#

    Purpose

      ZLDPERM finds a row permutation so that the matrix has large
      entries on the diagonal.

#

    Arguments

    job    (input) int
           Control the action. Possible values for JOB are:
           = 1 : Compute a row permutation of the matrix so that the
                 permuted matrix has as many entries on its diagonal as
                 possible. The values on the diagonal are of arbitrary size.
                 HSL subroutine MC21A/AD is used for this.
           = 2 : Compute a row permutation of the matrix so that the smallest
                 value on the diagonal of the permuted matrix is maximized.
           = 3 : Compute a row permutation of the matrix so that the smallest
                 value on the diagonal of the permuted matrix is maximized.
                 The algorithm differs from the one used for JOB = 2 and may
                 have quite a different performance.
           = 4 : Compute a row permutation of the matrix so that the sum
                 of the diagonal entries of the permuted matrix is maximized.
           = 5 : Compute a row permutation of the matrix so that the product
                 of the diagonal entries of the permuted matrix is maximized
                 and vectors to scale the matrix so that the nonzero diagonal
                 entries of the permuted matrix are one in absolute value and
                 all the off-diagonal entries are less than or equal to one in
                 absolute value.
           Restriction: 1 <= JOB <= 5.

    n      (input) int
           The order of the matrix.

    nnz    (input) int
           The number of nonzeros in the matrix.

    adjncy (input) int*, of size nnz
           The adjacency structure of the matrix, which contains the row
           indices of the nonzeros.

    colptr (input) int*, of size n+1
           The pointers to the beginning of each column in ADJNCY.

    nzval  (input) doublecomplex*, of size nnz
           The nonzero values of the matrix. nzval[k] is the value of
           the entry corresponding to adjncy[k].
           It is not used if job = 1.

    perm   (output) int*, of size n
           The permutation vector. perm[i] = j means row i in the
           original matrix is in row j of the permuted matrix.

    u      (output) double*, of size n
           If job = 5, the natural logarithms of the row scaling factors.

    v      (output) double*, of size n
           If job = 5, the natural logarithms of the column scaling factors.
           The scaled matrix B has entries b_ij = a_ij * exp(u_i + v_j).

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