KmlIssCgSetUserPreconditioner?I
Interface Definition
C interface:
int KmlIssCgSetUserPreconditionerSI(KmlSolverTask **handle, void *ustruct, int (*fptr)(void *ustruct, float *x));
int KmlIssCgSetUserPreconditionerDI(KmlSolverTask **handle, void *ustruct, int (*fptr)(void *ustruct, double *x));
Parameters
Parameter |
Type |
Description |
Input/Output |
|---|---|---|---|
handle |
KmlSolverTask ** |
Solver handle, which transfers a variable defined previously. |
Input/Output |
ustruct |
void * |
Pointer to user data. This parameter is transferred as the first parameter each time the preconditioner is called. |
Input |
(*fptr) |
int |
User-defined function pointer to the callback function. The callback function performs calculation between the preconditioner and the second parameter of the preconditioner. |
Input |
Return Value
Return Value |
Type |
Description |
|---|---|---|
KMLSS_NO_ERROR |
int |
The execution is successful. |
KMLSS_NULL_ARGUMENT |
int |
A null argument exists in {handle, fptr}. |
Dependency
#include "kml_iss.h"
Example
class pc
{
public:
int n;
double *b;
};
int mut(void *unstruct,double *x)
{
/*
Compute the product of the precondition matrix and the vector x,
the precondition matrix is a diagonal matrix
*/
int n;
pc *a;
a = (pc *)unstruct;
n = a->n;
for(int i=0; i<n; i++){
x[i] = x[i] * a->b[i];
}
return 0;
}
KmlSolverTask *handle;
int ierr;
int n = 8;
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 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};
int ia[9] = {0, 3, 7, 10, 14, 17, 21, 23, 26};
pc *unstruct = new pc;
unstruct->b = new double [n];
for(int i=0; i<n; i++){
unstruct->b[i] = 2;
}
ierr = KmlIssCgInitDI(&handle, n, a, ja, ia);
ierr = KmlIssCgSetUserPreconditionerDI(&handle, unstruct, mut);
if (ierr != 0) {
printf("\nERROR in KmlIssCgSetUserPreconditionerDI: %d", ierr);
return 1;
}