KmlScaissGmresSubPcSet?I?

Set the parameters related to the Block-Jacobi sub-preconditioners in the iterative solution.

Interface Definition

C interface:

int KmlScaissGmresSubPcSetSII(KmlScasolverTask **handle, enum KmlSolverPreconditionerParam param, int subn, const int *data, int nd);

int KmlScaissGmresSubPcSetDII(KmlScasolverTask **handle, enum KmlSolverPreconditionerParam param, int subn, const int *data, int nd);

int KmlScaissGmresSubPcSetSIS(KmlScasolverTask **handle, enum KmlSolverPreconditionerParam param, int subn, const float *data, int nd);

int KmlScaissGmresSubPcSetDID(KmlScasolverTask **handle, enum KmlSolverPreconditionerParam param, int subn, const double *data, int nd);

Parameters

Parameter	Type	Description	Input/Output
handle	KmlScasolverTask **	Solver handle, which is a variable passed from a previous step.	Input/Output
param	enum KmlSolverParam	KML_RELAXATION_FACTOR indicates the parameters related to the SOR preconditioner. KMLSS_DROP_FILL indicates the maximum number of elements to be retained per row for the ILUT preconditioner. KMLSS_DROP_TOL indicates the threshold for retaining elements for the ILUT preconditioner.	Input
subn	int in KmlScaissGmresSubPcSetSIS/KmlScaissGmresSubPcSetSII/KmlScaissGmresSubPcSetDII/KmlScaissGmresSubPcSetDID	Index of a sub-preconditioner.	Input
data	const int * in KmlScaissGmresSubPcSetSII/KmlScaissGmresSubPcSetDII const float * in KmlScaissGmresSubPcSetSIS const double * in KmlScaissGmresSubPcSetDID	Parameters related to the preconditioner.	Input
nd	int in KmlScaissGmresSubPcSetSII/KmlScaissGmresSubPcSetSIS/KmlScaissGmresSubPcSetDII/KmlScaissGmresSubPcSetDID	Number of elements in the data array.	Input

Return Value

Return Value	Type	Description
KMLSS_NO_ERROR	int	Normal execution.
KMLSS_DATA_SIZE	int	The value of nd is not 1.
KMLSS_NULL_ARGUMENT	int	A null argument exists in {handle, data}.
KMLSS_BAD_SELECTOR	int	param is invalid.
KMLSS_BAD_PRECONDITIONER	int	The selected preconditioner has not been implemented.

Dependencies

#include "kml_scaiss.h"

Examples

C interface:

MPI_Init(NULL, NULL);
int size, rank;
MPI_Comm_size(MPI_COMM_WORLD, &size);// Obtain the total number of processes.
MPI_Comm_rank(MPI_COMM_WORLD, &rank);// Obtain the current rank.

int mat_size = 8;
int n = mat_size / size;
int n_beg = n * rank;
if (n * size != mat_size && rank == (size - 1)) {
    n = mat_size - n * rank;
}
int ja[26] = { 0, 3, 4, 1, 2, 3, 5, 1, 2, 7, 0, 1, 3, 6, 0, 4, 5, 1, 4, 5, 7, 3, 6, 2, 5, 7 };
double a[26] = { 1.0, 1.0, 2.0, 9.0, 2.0, 1.0, -3.0, 2.0, 3.0, 2.0, 1.0, 1.0, 9.0, -5.0, 2.0, 6.0, 1.0, -3.0, 1.0, 4.0, 1.0, -5.0, 7.0, 2.0, 1.0, 2.0 };
int ia[9] = { 0, 3, 7, 10, 14, 17, 21, 23, 26 };
int a_beg = ia[n_beg];
for (int i = n_beg; i < (n_beg + n + 1); i++) {
    ia[i] -= a_beg;
}

/* Internal KML_SCAISS structure */
KmlScasolverTask *handle;

/* KML_SCAISS control parameters */
int error;            /* Output error handle */

/* Create data structures */
const double *a_holder = &a[a_beg];
const int *ja_holder = &ja[a_beg];
const int *ia_holder = &ia[n_beg];
error = KmlScaissGmresInitStripesDI(&handle, mat_size, 1, &n, &n_beg, &a_holder, &ja_holder, &ia_holder, MPI_COMM_WORLD);

double eps = 1e-4;
error = KmlScaissGmresSetDID(&handle, KMLSS_THRESHOLD, &eps, 1); 
if (error != 0) {
    printf("\nERROR in KmlScaissGmresSetDID with KMLSS_THRESHOLD: %d", error);
    return 1;
}
int max_iters = 2000;
error = KmlScaissGmresSetDII(&handle, KMLSS_MAX_ITERATION_COUNT, &max_iters, 1);
if (error != 0) {
    printf("\nERROR in KmlScaissGmresSetDII with KMLSS_MAX_ITERATION_COUNT: %d", error);
    return 1;
}
int precond = KMLSS_BJACOBI;
error = KmlScaissGmresSetDII(&handle, KMLSS_PRECONDITIONER_TYPE, &precond, 1);
if (error != 0) {
    printf("\nERROR in KmlScaissGmresSetDII with KMLSS_PRECONDITIONER_TYPE: %d", error);
    return 1;
}
int num_blocks = 1;
error = KmlScaissGmresPcSetDII(&handle, KMLSS_NUM_BLOCKS, &num_blocks, 1);
if (error != 0) {
	printf("ERROR in KmlScaissGmresPcSetDII: %d\n", error);
	return 1;
}
int subprecond = KMLSS_ICC;
error = KmlScaissGmresPcSetDII(&handle, KMLSS_BLOCK_METHOD, &subprecond, 1);
if (error != 0) {
    printf("ERROR in KmlScaissGmresPcSetDII: %d\n", error);
    return 1;
}

Parent topic: SCAISS-GMRES