ditersol1.c File Reference

Example #2 showing how to use ILU to precondition GMRES. More...

#include "slu_ddefs.h"

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Functions
void	dpsolve (int n, double x[], double y[])
void	dmatvec_mult (double alpha, double x[], double beta, double y[])
int	main (int argc, char *argv[])

Variables
char *	GLOBAL_EQUED
superlu_options_t *	GLOBAL_OPTIONS
double *	GLOBAL_R
double *	GLOBAL_C
int *	GLOBAL_PERM_C
int *	GLOBAL_PERM_R
SuperMatrix *	GLOBAL_A
SuperMatrix *	GLOBAL_A_ORIG
SuperMatrix *	GLOBAL_L
SuperMatrix *	GLOBAL_U
SuperLUStat_t *	GLOBAL_STAT
mem_usage_t *	GLOBAL_MEM_USAGE

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 5.0) –
Lawrence Berkeley National Laboratory
November, 2010
August, 2011

This example shows that ILU is computed from the equilibrated matrix,
but the preconditioned GMRES is applied to the original system.
The driver routine DGSISX is called twice to perform factorization
and apply preconditioner separately.

Note that DGSISX performs the following factorization:
    Pr*Dr*A*Dc*Pc^T ~= LU
with Pr being obtained from MC64 statically then partial pivoting
dynamically. On return, A is overwritten as A1 = Dr*A*Dc.

We need to save a copy of the original matrix A, then solve
the original system, A*x = B, using FGMRES.
Each GMRES step requires requires 2 procedures:
  1) Apply preconditioner M^{-1} = Dc*Pc^T*U^{-1}*L^{-1}*Pr*Dr
  2) Matrix-vector multiplication: w = A*v

Function Documentation

void dmatvec_mult	(	double	alpha,
		double	x[],
		double	beta,
		double	y[]
	)

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void dpsolve	(	int	n,
		double	x[],
		double	y[]
	)

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int main	(	int	argc,
		char *	argv[]
	)

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Variable Documentation

SuperMatrix* GLOBAL_A

SuperMatrix * GLOBAL_A_ORIG

double * GLOBAL_C

char* GLOBAL_EQUED

SuperMatrix * GLOBAL_L

mem_usage_t* GLOBAL_MEM_USAGE

superlu_options_t* GLOBAL_OPTIONS

int* GLOBAL_PERM_C

int * GLOBAL_PERM_R

double* GLOBAL_R

SuperLUStat_t* GLOBAL_STAT

SuperMatrix * GLOBAL_U