A special purpose adaptation algorithm. consider using adapt_wavelet() instead.

struct Adapt_Field {
scalar f;       // The field with leaf-filled values
double max;     // refinement criterion
double min;     // coarseing criterion
int maxlevel;   // maximum level of refinement
int minlevel;   // minimum level of refinement (default 1)
scalar * list;  // list of fields to update (default all)
};

trace
scalar f = p.f;
if (p.list == NULL)
p.list = all;
scalar * listc = NULL;
for (scalar s in p.list)
if (!is_constant(s) && s.restriction != no_restriction)
astats st = {0, 0};
// refinement
if (p.minlevel < 1)
p.minlevel = 1;
tree->refined.n = 0;
static const int refined = 1 << user, too_fine = 1 << (user + 1);
foreach_cell() {
if (is_active(cell)) {
static const int too_coarse = 1 << (user + 2);
if (is_leaf (cell)) {
if (cell.flags & too_coarse) {
cell.flags &= ~too_coarse;
refine_cell (point, listc, refined, &tree->refined);
st.nf++;
}
continue;
}
else { // !is_leaf (cell)
if (cell.flags & refined) {
// cell has already been refined, skip its children
cell.flags &= ~too_coarse;
continue;
}
// check whether the cell or any of its children is local
bool local = is_local(cell);
if (!local)
foreach_child()
if (is_local(cell))
local = true, break;
if (local) {
static const int just_fine = 1 << (user + 3);
double max = p.max, min = p.min;
foreach_child() {
double e = fabs(f[]);
if (e > max && level < p.maxlevel) {
cell.flags &= ~too_fine;
cell.flags |= too_coarse;
}
else if ((e <= min || level > p.maxlevel) &&
!(cell.flags & (too_coarse|just_fine))) {
if (level >= p.minlevel)
cell.flags |= too_fine;
}
else if (!(cell.flags & too_coarse)) {
cell.flags &= ~too_fine;
cell.flags |= just_fine;
}
}
foreach_child() {
cell.flags &= ~just_fine;
if (!is_leaf(cell)) {
cell.flags &= ~too_coarse;
if (level >= p.maxlevel)
cell.flags |= too_fine;
}
else if (!is_active(cell))
cell.flags &= ~too_coarse;
}
}
}
}
else // inactive cell
continue;
}
mpi_boundary_refine (listc);
// coarsening
// the loop below is only necessary to ensure symmetry of 2:1 constraint
for (int l = depth(); l >= 0; l--) {
foreach_cell()
if (!is_boundary(cell)) {
if (level == l) {
if (!is_leaf(cell)) {
if (cell.flags & refined)
// cell was refined previously, unset the flag
cell.flags &= ~(refined|too_fine);
else if (cell.flags & too_fine) {
if (is_local(cell) && coarsen_cell (point, listc))
st.nc++;
cell.flags &= ~too_fine; // do not coarsen parent
}
}
if (cell.flags & too_fine)
cell.flags &= ~too_fine;
else if (level > 0 && (aparent(0).flags & too_fine))
aparent(0).flags &= ~too_fine;
continue;
}
else if (is_leaf(cell))
continue;
}
mpi_boundary_coarsen (l, too_fine);
}
free (listc);
mpi_all_reduce (st.nf, MPI_INT, MPI_SUM);
mpi_all_reduce (st.nc, MPI_INT, MPI_SUM);
if (st.nc || st.nf)
mpi_boundary_update (p.list);
return st;
}