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Correct FMG routine to start prolongation at the proper level #124

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Merged
julianlitz merged 5 commits into from
Sep 23, 2025
Merged

Correct FMG routine to start prolongation at the proper level #124

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705bc13
FMG didnt start at the correct level
julianlitz Sep 22, 2025
ff886e7
Improve naming
julianlitz Sep 22, 2025
e79f094
small name change
julianlitz Sep 22, 2025
dc41867
Simplify names further
julianlitz Sep 22, 2025
0e7dff9
Revert comment
julianlitz Sep 22, 2025
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42 changes: 21 additions & 21 deletions src/GMGPolar/solver.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -194,38 +194,38 @@ void GMGPolar::initializeSolution()
}
else {
// Start from the coarsest level
int FMG_start_level_depth = number_of_levels_ - 1;
Level& FMG_level = levels_[FMG_start_level_depth];
int coarsest_depth = number_of_levels_ - 1;
Level& coarsest_level = levels_[coarsest_depth];

// Solve directly on the coarsest level
FMG_level.solution() = FMG_level.rhs();
FMG_level.directSolveInPlace(FMG_level.solution()); // Direct solve on coarsest grid
coarsest_level.solution() = coarsest_level.rhs();
coarsest_level.directSolveInPlace(coarsest_level.solution()); // Direct solve on coarsest grid

// Prolongate the solution from the coarsest level up to the finest, while applying Multigrid Cycles on each level
for (int current_level = FMG_start_level_depth - 1; current_level > 0; --current_level) {
Level& FMG_level = levels_[current_level]; // The current level
Level& next_FMG_level = levels_[current_level - 1]; // The finer level
for (int depth = coarsest_depth; depth > 0; --depth) {
Level& coarse_level = levels_[depth]; // Current coarse level
Level& fine_level = levels_[depth - 1]; // Next finer level

// The bi-cubic FMG interpolation is of higher order
FMGInterpolation(current_level, next_FMG_level.solution(), FMG_level.solution());
FMGInterpolation(coarse_level.level_depth(), fine_level.solution(), coarse_level.solution());

// Apply some FMG iterations
for (int i = 0; i < FMG_iterations_; i++) {
if (current_level - 1 == 0 && (extrapolation_ != ExtrapolationType::NONE)) {
if (fine_level.level_depth() == 0 && (extrapolation_ != ExtrapolationType::NONE)) {
switch (FMG_cycle_) {
case MultigridCycleType::V_CYCLE:
implicitlyExtrapolatedMultigrid_V_Cycle(current_level - 1, next_FMG_level.solution(),
next_FMG_level.rhs(), next_FMG_level.residual());
implicitlyExtrapolatedMultigrid_V_Cycle(fine_level.level_depth(), fine_level.solution(),
fine_level.rhs(), fine_level.residual());
break;

case MultigridCycleType::W_CYCLE:
implicitlyExtrapolatedMultigrid_W_Cycle(current_level - 1, next_FMG_level.solution(),
next_FMG_level.rhs(), next_FMG_level.residual());
implicitlyExtrapolatedMultigrid_W_Cycle(fine_level.level_depth(), fine_level.solution(),
fine_level.rhs(), fine_level.residual());
break;

case MultigridCycleType::F_CYCLE:
implicitlyExtrapolatedMultigrid_F_Cycle(current_level - 1, next_FMG_level.solution(),
next_FMG_level.rhs(), next_FMG_level.residual());
implicitlyExtrapolatedMultigrid_F_Cycle(fine_level.level_depth(), fine_level.solution(),
fine_level.rhs(), fine_level.residual());
break;

default:
Expand All @@ -237,18 +237,18 @@ void GMGPolar::initializeSolution()
else {
switch (FMG_cycle_) {
case MultigridCycleType::V_CYCLE:
multigrid_V_Cycle(current_level - 1, next_FMG_level.solution(), next_FMG_level.rhs(),
next_FMG_level.residual());
multigrid_V_Cycle(fine_level.level_depth(), fine_level.solution(), fine_level.rhs(),
fine_level.residual());
break;

case MultigridCycleType::W_CYCLE:
multigrid_W_Cycle(current_level - 1, next_FMG_level.solution(), next_FMG_level.rhs(),
next_FMG_level.residual());
multigrid_W_Cycle(fine_level.level_depth(), fine_level.solution(), fine_level.rhs(),
fine_level.residual());
break;

case MultigridCycleType::F_CYCLE:
multigrid_F_Cycle(current_level - 1, next_FMG_level.solution(), next_FMG_level.rhs(),
next_FMG_level.residual());
multigrid_F_Cycle(fine_level.level_depth(), fine_level.solution(), fine_level.rhs(),
fine_level.residual());
break;

default:
Expand Down
10 changes: 5 additions & 5 deletions tests/GMGPolar/solve_tests.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -190,7 +190,7 @@ using gmgpolar_test_suite = testing::Types<
std::integral_constant<ResidualNormType, ResidualNormType::EUCLIDEAN>, // residualNormType
std::integral_constant<double, 1e-8>, // absoluteTolerance
std::integral_constant<double, 1e-8>, // relativeTolerance
std::integral_constant<int, 28>, // expected_iterations
std::integral_constant<int, 26>, // expected_iterations
std::integral_constant<double, 2e-6>, // expected_l2_error
std::integral_constant<double, 9e-6>, // expected_inf_error
std::integral_constant<double, 0.7> // expected_residual_reduction
Expand Down Expand Up @@ -227,7 +227,7 @@ using gmgpolar_test_suite = testing::Types<
std::integral_constant<ResidualNormType, ResidualNormType::EUCLIDEAN>, // residualNormType
std::integral_constant<double, 1e-8>, // absoluteTolerance
std::integral_constant<double, 1e-8>, // relativeTolerance
std::integral_constant<int, 28>, // expected_iterations
std::integral_constant<int, 26>, // expected_iterations
std::integral_constant<double, 2e-6>, // expected_l2_error
std::integral_constant<double, 9e-6>, // expected_inf_error
std::integral_constant<double, 0.7> // expected_residual_reduction
Expand Down Expand Up @@ -264,7 +264,7 @@ using gmgpolar_test_suite = testing::Types<
std::integral_constant<ResidualNormType, ResidualNormType::EUCLIDEAN>, // residualNormType
std::integral_constant<double, 1e-8>, // absoluteTolerance
std::integral_constant<double, 1e-8>, // relativeTolerance
std::integral_constant<int, 28>, // expected_iterations
std::integral_constant<int, 26>, // expected_iterations
std::integral_constant<double, 2e-6>, // expected_l2_error
std::integral_constant<double, 9e-6>, // expected_inf_error
std::integral_constant<double, 0.7> // expected_residual_reduction
Expand Down Expand Up @@ -299,7 +299,7 @@ using gmgpolar_test_suite = testing::Types<
std::integral_constant<ResidualNormType, ResidualNormType::INFINITY_NORM>, // residualNormType
std::integral_constant<double, 1e-12>, // absoluteTolerance
std::integral_constant<double, 1e-10>, // relativeTolerance
std::integral_constant<int, 14>, // expected_iterations
std::integral_constant<int, 12>, // expected_iterations
std::integral_constant<double, 6e-6>, // expected_l2_error
std::integral_constant<double, 2e-5>, // expected_inf_error
std::integral_constant<double, 0.3> // expected_residual_reduction
Expand Down Expand Up @@ -472,7 +472,7 @@ using gmgpolar_test_suite = testing::Types<
std::integral_constant<ResidualNormType, ResidualNormType::WEIGHTED_EUCLIDEAN>, // residualNormType
std::integral_constant<double, 1e-8>, // absoluteTolerance
std::integral_constant<double, -1.0>, // relativeTolerance
std::integral_constant<int, 15>, // expected_iterations
std::integral_constant<int, 14>, // expected_iterations
std::integral_constant<double, 9e-5>, // expected_l2_error
std::integral_constant<double, 3e-4>, // expected_inf_error
std::integral_constant<double, 0.6> // expected_residual_reduction
Expand Down