KmlScaissCgInitStripes?I

Initialize the data structure and associate a provided coefficient matrix with the solution system. The complete matrix in CSR format is used when the CG method for clusters is initialized.

Interface Definition

C interface:

int KmlScaissCgInitStripesSI(KmlScasolverTask **handle, int n, int nstripes, const int *stripeWidth,const int *stripeRow, const float * const *a, const int * const *ja, const int * const *ia, MPI_Comm comm);

int KmlScaissCgInitStripesDI(KmlScasolverTask **handle, int n, int nstripes, const int *stripeWidth, const int *stripeRow, const double * const *a, const int * const *ja, const int * const *ia, MPI_Comm comm);

Parameters

Parameter	Type	Description	Input/Output
handle	KmlScasolverTask **	Solver handle. handle cannot be a null pointer.	Input/Output
n	int	Dimension of matrix A.	Input
nstripes	int	Number of band matrices stored in the related MPI process. Currently, the value can only be 1.	Input
stripeWidth	int	Array containing the number of rows in a band matrix, with a length of nstripes stripeWidth[i] indicates the number of rows in the i-th band matrix. The lifecycle of this array is the same as that of handle.	Input
stripeRow	int	Array containing the global coordinates of specific row numbers in a band matrix, with a length of nstripes. stripeRow[i] indicates the row number in the global matrix that corresponds to the first row of the i-th band matrix. The lifecycle of this array is the same as that of handle.	Input
a	float * in KmlScaissCgInitStripesSI double * in KmlScaissCgInitStripesDI	Array whose dimension is the quantity of non-zero elements. a[i] is the value of the i-th non-zero element. The lifecycle of this array is the same as that of handle.	Input
ja	int	Array whose dimension is the quantity of non-zero elements. ja[i] is the column number of the i-th non-zero element. The lifecycle of this array is the same as that of handle.	Input
ia	int	(n+1)-dimensional array. ia[i] is the index of the first non-zero element in the i-th row in all non-zero elements. The lifecycle of this array is the same as that of handle.	Input
comm	MPI_Comm	Communicator of the MPI process.	Input

Return Values

Return Value	Type	Description
KMLSS_NO_ERROR	int	The execution is successful.
KMLSS_NULL_ARGUMENT	int	A null argument exists in {handle, stripeWidth, stripeRow, a, ja, ia}.
KMLSS_BAD_N	int	The value of parameter n is not an integer.
KMLSS_NOT_IMPLEMENTED	int	The value of nstripes is not 1.
KMLSS_NO_MEMORY	int	The memory is insufficient.

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 process ID.

int n = 8 / size;
int n_beg = n * rank;
if (n * size != 8 && rank == (size - 1)) {
    n = 8 - 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, 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 < 9; 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 = KmlScaissCgInitStripesDI(&handle, 8, 1, &n, &n_beg, &a_holder, &ja_holder, &ia_holder, MPI_COMM_WORLD);
if (error != 0) {
    printf("\nERROR in KmlScaissCgInitStripesDI: %d", error);
    return 1;
    }

Parent topic: SCAISS-CG