/*
* Jacobi smoother.
*
* Implement using phgMatvec
* ref: phgSolverJacobi, solver-phg.c
* */
void
mg_Jacobi(MAT *A, VEC *x, VEC *b, int nsmooth, void *ctx)
{
VEC *r;
INT i, k;
FLOAT dx, omega = _p->smooth_damp;
if (A->diag == NULL)
phgMatSetupDiagonal(A);
r = phgMapCreateVec(b->map, 1);
for (k = 0; k < nsmooth; k++) {
phgVecCopy(b, &r);
phgMatVec(MAT_OP_N, -1.0, A, x, 1.0, &r);
for (i = 0; i < A->cmap->nlocal; i++) {
assert(fabs(A->diag[i]) > 1e-12);
dx = r->data[i] / A->diag[i];
x->data[i] += omega * dx;
}
}
phgVecDestroy(&r);
return;
}
static void
build_matrices(MAT *matA, MAT *matM, MAT *matC, MAT *S, FLOAT s,
DOF *u_h, DOF *p_h)
/* S is used to store s*diag(M(p_h))^(-1) */
{
int N = u_h->type->nbas; /* number of basis functions in an element */
int M = p_h->type->nbas;
int i, j;
GRID *g = u_h->g;
ELEMENT *e;
FLOAT A[N][N], B[N][N], C[N][M];
INT I[N], Ip[M];
INT k, n0;
VEC *V = phgMapCreateVec(S->rmap, 1);
phgVecDisassemble(V); /* for phgVecAddEntry */
ForAllElements(g, e) {
for (i = 0; i < N; i++) {
I[i] = phgMapE2L(matA->rmap, 0, e, i);
for (k = 0; k < M; k++) {
/* \int \grad\psi_k\cdot\phi_i */
C[i][k] = phgQuadGradBasDotBas(e, p_h, k, u_h, i, QUAD_DEFAULT);
}
for (j = 0; j <= i; j++) {
/* \int \phi_i\cdot\phi_j */
B[j][i] = B[i][j] =
phgQuadBasDotBas(e, u_h, j, u_h, i, QUAD_DEFAULT);
/* \int \curl\phi_i\cdot\curl\phi_j */
A[j][i] = A[i][j] =
phgQuadCurlBasDotCurlBas(e, u_h, j, u_h, i, QUAD_DEFAULT);
}
}
for (i = 0; i < M; i++) {
Ip[i] = phgMapE2L(matC->cmap, 0, e, i);
if (Ip[i] < 0) /* boundary entry */
continue;
phgVecAddEntry(V, 0, Ip[i],
phgQuadBasDotBas(e, p_h, i, p_h, i, QUAD_DEFAULT));
}
/* loop on basis functions */
for (i = 0; i < N; i++) {
if (phgDofDirichletBC(u_h, e, i, NULL, NULL, NULL, DOF_PROJ_CROSS))
continue;
phgMatAddEntries(matA, 1, I + i, N, I, A[i]);
phgMatAddEntries(matM, 1, I + i, N, I, B[i]);
phgMatAddEntries(matC, 1, I + i, M, Ip, C[i]);
}
}
phgVecAssemble(V);
n0 = V->map->partition[V->map->rank];
for (k = 0; k < V->map->nlocal; k++)
phgMatAddGlobalEntry(S, k + n0, k + n0, s / V->data[k]);
phgVecDestroy(&V);
phgMatAssemble(S);
phgMatSetupDiagonal(S);
phgMatAssemble(matA);
phgMatAssemble(matM);
phgMatAssemble(matC);
}
