KmlScaissBicgstabSet?I?

Set parameters related to iterative solution.

Interface Definition

C interface:

int KmlScaissBicgstabSetSII(KmlScasolverTask **handle, enum KmlSolverParam param, const int *data, int nd);

int KmlScaissBicgstabSetSIS(KmlScasolverTask **handle, enum KmlSolverParam param, const float *data, int nd);

int KmlScaissBicgstabSetDII(KmlScasolverTask **handle, enum KmlSolverParam param, const int *data, int nd);

int KmlScaissBicgstabSetDID(KmlScasolverTask **handle, enum KmlSolverParam param, const double *data, int nd);

Parameters

Parameter	Type	Description	Input/Output
handle	KmlScasolverTask **	Solver handle, which transfers a variable defined previously.	Input/Output
param	enum KmlSolverParam	KMLSS_THRESHOLD indicates the relative threshold for iteration residuals. KMLSS_ABS_TOLERANCE indicates the absolute threshold for iteration residuals. KMLSS_MAX_ITERATION_COUNT indicates the maximum number of iterations. KMLSS_PRECONDITIONER_TYPE indicates the preconditioner type. KMLSS_VECTOR_NORM_TYPE indicates the norm for computing the iteration residual. KMLSS_MATRIX_FORMAT indicates the sparse storage format for diagonal blocks of a matrix. KMLSS_OFFDIAG_MATRIX_FORMAT indicates the sparse storage format for non-diagonal blocks of a matrix.	Input
data	const int * in KmlScaissBicgstabSetSII/ KmlScaissBicgstabSetDII const float * in KmlScaissBicgstabSetSIS const double * in KmlScaissBicgstabSetDID	Iterative solution-related parameter array (such as thresholds, maximum number of iterations, etc.). Currently available norms for computation: 1-NORM: KMLSS_L1 2-NORM: KMLSS_L2 Currently available sparse matrix storage formats: CSR format: KMLSS_CSR ELLPACK format: KMLSS_ELL COO format: KMLSS_COO ELLPACK_COO hybrid format: KMLSS_SELLCOO Available preconditioner types: JACOBI preconditioner: KMLSS_JACOBI Block JACOBI preconditioner: KMLSS_BJACOBI AMG preconditioner: KMLSS_AMG	Input
nd	int	Number of elements in the data array.	Input

Return Values

Return Value	Type	Description
KMLSS_NO_ERROR	int	The execution is successful.
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	Parameter param is invalid.
KMLSS_BAD_PRECONDITIONER	int	The selected preconditioner has not been implemented.

Dependency

#include "kml_scaiss.h"

Example

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 = KmlScaissBicgstabInitStripesDI(&handle, mat_size, 1, &n, &n_beg, &a_holder, &ja_holder, &ia_holder, MPI_COMM_WORLD);

double eps = 1e-4;
error = KmlScaissBicgstabSetDID(&handle, KMLSS_THRESHOLD, &eps, 1); 
if (error != 0) {
    printf("\nERROR in KmlScaissBicgstabSetDID with KMLSS_THRESHOLD: %d", error);
    return 1;
}
int max_iters = 2000;
error = KmlScaissBicgstabSetDII(&handle, KMLSS_MAX_ITERATION_COUNT, &max_iters, 1);
if (error != 0) {
    printf("\nERROR in KmlScaissBicgstabSetDII with KMLSS_MAX_ITERATION_COUNT: %d", error);
    return 1;
}
int precond = KMLSS_BJACOBI;
error = KmlScaissBicgstabSetDII(&handle, KMLSS_PRECONDITIONER_TYPE, &precond, 1);
if (error != 0) {
    printf("\nERROR in KmlScaissBicgstabSetDII with KMLSS_PRECONDITIONER_TYPE: %d", error);
    return 1;
}

Parent topic: SCAISS-BICGSTAB