SuperLU_DIST  4.0
superlu_dist on CPU and GPU clusters
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Macros | Functions
get_perm_c.c File Reference

Gets matrix permutation. More...

#include "superlu_ddefs.h"

Macros

#define METISOPTIONS   40
 

Functions

void get_metis (int_t n, int_t bnz, int_t *b_colptr, int_t *b_rowind, int_t *perm_c)
 
void getata_dist (const int_t m, const int_t n, const int_t nz, int_t *colptr, int_t *rowind, int_t *atanz, int_t **ata_colptr, int_t **ata_rowind)
 
void at_plus_a_dist (const int_t n, const int_t nz, int_t *colptr, int_t *rowind, int_t *bnz, int_t **b_colptr, int_t **b_rowind)
 
void get_perm_c_dist (int_t pnum, int_t ispec, SuperMatrix *A, int_t *perm_c)
 

Detailed Description

Gets matrix permutation.

-- Distributed SuperLU routine (version 2.1) --
Lawrence Berkeley National Lab, Univ. of California Berkeley,
November 1, 2007
Feburary 20, 2008

Last update: 7/27/2011 fix a bug with metis ordering on empty graph.

Macro Definition Documentation

#define METISOPTIONS   40

Function Documentation

void at_plus_a_dist ( const int_t  n,
const int_t  nz,
int_t colptr,
int_t rowind,
int_t bnz,
int_t **  b_colptr,
int_t **  b_rowind 
)

Purpose

Form the structure of A'+A. A is an n-by-n matrix in column oriented
format represented by (colptr, rowind). The output A'+A is in column
oriented format (symmetrically, also row oriented), represented by
(b_colptr, b_rowind).
void get_metis ( int_t  n,
int_t  bnz,
int_t b_colptr,
int_t b_rowind,
int_t perm_c 
)
void get_perm_c_dist ( int_t  pnum,
int_t  ispec,
SuperMatrix A,
int_t perm_c 
)

Purpose

GET_PERM_C_DIST obtains a permutation matrix Pc, by applying the multiple
minimum degree ordering code by Joseph Liu to matrix A'*A or A+A',
or using approximate minimum degree column ordering by Davis et. al.
The LU factorization of A*Pc tends to have less fill than the LU 
factorization of A.

Arguments

ispec   (input) colperm_t
        Specifies what type of column permutation to use to reduce fill.
        = NATURAL: natural ordering (i.e., Pc = I)
        = MMD_AT_PLUS_A: minimum degree ordering on structure of A'+A
        = MMD_ATA: minimum degree ordering on structure of A'*A
        = METIS_AT_PLUS_A: MeTis on A'+A
A       (input) SuperMatrix*
        Matrix A in A*X=B, of dimension (A->nrow, A->ncol). The number
        of the linear equations is A->nrow. Currently, the type of A 
        can be: Stype = SLU_NC; Dtype = SLU_D; Mtype = SLU_GE.
        In the future, more general A can be handled.
perm_c  (output) int*
    Column permutation vector of size A->ncol, which defines the 
        permutation matrix Pc; perm_c[i] = j means column i of A is 
        in position j in A*Pc.
void getata_dist ( const int_t  m,
const int_t  n,
const int_t  nz,
int_t colptr,
int_t rowind,
int_t atanz,
int_t **  ata_colptr,
int_t **  ata_rowind 
)

Purpose

Form the structure of A'*A. A is an m-by-n matrix in column oriented
format represented by (colptr, rowind). The output A'*A is in column
oriented format (symmetrically, also row oriented), represented by
(ata_colptr, ata_rowind).
This routine is modified from GETATA routine by Tim Davis.
The complexity of this algorithm is: SUM_{i=1,m} r(i)^2,
i.e., the sum of the square of the row counts.

Questions

    o  Do I need to withhold the dense rows?
    o  How do I know the number of nonzeros in A'*A?