/*!
@param[in] A the known system matrix
@param[in] r the input vector
@param[inout] x On exit contains the result of the multigrid V-cycle with r as the RHS, x is the approximation to Ax = r.
@return returns 0 upon success and non-zero otherwise
@see ComputeMG_ref
*/
int ComputeMG(const SparseMatrix & A, const Vector & r, Vector & x) {
// This line and the next two lines should be removed and your version of ComputeSYMGS should be used.
if(A.optimizationData == 0 || r.optimizationData == 0 || x.optimizationData == 0){
A.isMgOptimized = false;
return ComputeMG_ref(A, r, x);
}
assert(x.localLength==A.localNumberOfColumns); // Make sure x contain space for halo values
ZeroVector(x); // initialize x to zero
int ierr = 0;
if (A.mgData!=0) { // Go to next coarse level if defined
int numberOfPresmootherSteps = A.mgData->numberOfPresmootherSteps;
for (int i=0; i< numberOfPresmootherSteps; ++i) ierr += ComputeSYMGS(A, r, x);
if (ierr!=0) return ierr;
ierr = ComputeSPMV(A, x, *A.mgData->Axf); if (ierr!=0) return ierr;
// Perform restriction operation using simple injection
ierr = ComputeRestriction(A, r); if (ierr!=0) return ierr;
ierr = ComputeMG(*A.Ac,*A.mgData->rc, *A.mgData->xc); if (ierr!=0) return ierr;
ierr = ComputeProlongation(A, x); if (ierr!=0) return ierr;
int numberOfPostsmootherSteps = A.mgData->numberOfPostsmootherSteps;
for (int i=0; i< numberOfPostsmootherSteps; ++i) ierr += ComputeSYMGS(A, r, x);
if (ierr!=0) return ierr;
}
else {
ierr = ComputeSYMGS(A, r, x);
if (ierr!=0) return ierr;
}
return 0;
}
/*!
@param[in] A the known system matrix.
@param[in] r the input vector.
@param[inout] x On exit contains the result of the multigrid V-cycle with r
as the RHS, x is the approximation to Ax = r.
@return returns 0 upon success and non-zero otherwise.
@see ComputeMG
*/
inline int
ComputeMG(
SparseMatrix &A,
Array<floatType> &r,
Array<floatType> &x,
Context ctx,
Runtime *lrt
) {
const auto *const Asclrs = A.sclrs->data();
assert(Asclrs);
// Make sure x contain space for halo values.
assert(x.length() == size_t(Asclrs->localNumberOfColumns));
// Initialize x to zero.
ZeroVector(x, ctx, lrt);
//
int ierr = 0;
// Go to next coarse level if defined
if (A.mgData != NULL) {
const int nPre = A.mgData->numberOfPresmootherSteps;
for (int i = 0; i < nPre; ++i) {
ierr += ComputeSYMGS(A, r, x, ctx, lrt);
}
if (ierr != 0) return ierr;
//
ierr = ComputeSPMV(A, x, *A.mgData->Axf, ctx, lrt);
if (ierr != 0) return ierr;
// Perform restriction operation using simple injection.
ierr = ComputeRestriction(A, r, ctx, lrt);
if (ierr != 0) return ierr;
//
ierr = ComputeMG(*A.Ac, *A.mgData->rc, *A.mgData->xc, ctx, lrt);
if (ierr != 0) return ierr;
//
ierr = ComputeProlongation(A, x, ctx, lrt);
if (ierr!=0) return ierr;
const int nPost = A.mgData->numberOfPostsmootherSteps;
for (int i = 0; i < nPost; ++i) {
ierr += ComputeSYMGS(A, r, x, ctx, lrt);
}
if (ierr != 0) return ierr;
}
else {
ierr = ComputeSYMGS(A, r, x, ctx, lrt);
if (ierr != 0) return ierr;
}
//
return 0;
}