From: Matthias Maier Date: Fri, 18 Jan 2019 21:01:55 +0000 (-0600) Subject: DoFTools: restructure set_periodicity_constraints, part III X-Git-Tag: v9.1.0-rc1~421^2~1 X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6f266bb072c917b7bce8a2d4635933a5e64cfc0c;p=dealii.git DoFTools: restructure set_periodicity_constraints, part III The last commit in this series fixes up the remainder of the set_periodicity_constraints function. --- diff --git a/source/dofs/dof_tools_constraints.cc b/source/dofs/dof_tools_constraints.cc index b885b604ae..fa4ee20c8d 100644 --- a/source/dofs/dof_tools_constraints.cc +++ b/source/dofs/dof_tools_constraints.cc @@ -1991,37 +1991,11 @@ namespace DoFTools if (no_entries > 1) { is_identity_constrained = false; - target = numbers::invalid_unsigned_int; break; } } } - // Fix up a rare corner case: - // - // Find out whether the current dof (living on face 2) also - // exists on face 1. If this is the case then both faces share - // the same dof and we are in one of two situations: - // - We are about to enter an identity constraint of the dof to - // itself. In this case simply do nothing. - // - Otherwise, we force the dof to zero. - { - bool continue_with_next_dof = false; - for (unsigned int j = 0; j < dofs_per_face; ++j) - if (dofs_2[i] == dofs_1[j]) - { - // Force dof to 0 if we do not have an identity - // constraint of the dof to itself. - if (!(is_identity_constrained && target == i)) - affine_constraints.add_line(dofs_2[i]); - - continue_with_next_dof = true; - } - - if (continue_with_next_dof) - continue; - } - // Next, we work on all constraints that are not identity // constraints, i.e., constraints that involve an interpolation // step that constrains the current dof (on face 2) to more than @@ -2039,8 +2013,8 @@ namespace DoFTools for (unsigned int jj = 0; jj < dofs_per_face; ++jj) { - // Query the correct face_index on face_1 respecting - // the given orientation: + // Get the correct dof index on face_1 respecting the + // given orientation: const unsigned int j = cell_to_rotated_face_index[fe.face_to_cell_index( jj, 0, face_orientation, face_flip, face_rotation)]; @@ -2055,126 +2029,79 @@ namespace DoFTools continue; } - // - // We are left with an equality constraint. - // + // We are left with an "identity constraint". - // Query the correct face_index on face_1 respecting the - // given orientation: + // Get the correct dof index on face_1 respecting the given + // orientation: const unsigned int j = cell_to_rotated_face_index[fe.face_to_cell_index( target, 0, face_orientation, face_flip, face_rotation)]; - if (affine_constraints.is_constrained(dofs_2[i])) + const bool face_2_constrained = + affine_constraints.is_constrained(dofs_2[i]); + const auto dof_left = face_2_constrained ? dofs_1[j] : dofs_2[i]; + const auto dof_right = face_2_constrained ? dofs_2[i] : dofs_1[j]; + factor = face_2_constrained ? 1. / factor : factor; + + // If both degrees of freedom are constrained, there is nothing we + // can do. Simply continue with the next dof. + if (affine_constraints.is_constrained(dof_left) && + affine_constraints.is_constrained(dof_right)) + continue; + + // We have to be careful that adding the current identity + // constraint does not create a constraint cycle. Thus, check for + // a dependency cycle: + + bool constraints_are_cyclic = true; + double cycle_factor = factor; + + for (auto test_dof = dof_right; test_dof != dof_left;) { - // If the two aren't already identity constrained (whichever - // way around) or already identical (in case of rotated - // periodicity constraints), then enter the constraint. - // Otherwise, there is nothing for us to do. - bool enter_constraint = false; - // see if this would add an identity constraint - // cycle - if (!affine_constraints.is_constrained(dofs_1[j])) + if (!affine_constraints.is_constrained(test_dof)) { - types::global_dof_index new_dof = dofs_2[i]; - while (new_dof != dofs_1[j]) - if (affine_constraints.is_constrained(new_dof)) - { - const std::vector< - std::pair> - *constraint_entries = - affine_constraints.get_constraint_entries(new_dof); - if (constraint_entries->size() == 1) - new_dof = (*constraint_entries)[0].first; - else - { - enter_constraint = true; - break; - } - } - else - { - enter_constraint = true; - break; - } + constraints_are_cyclic = false; + break; } - if (enter_constraint) - { - affine_constraints.add_line(dofs_1[j]); - affine_constraints.add_entry(dofs_1[j], dofs_2[i], factor); - } - } - else - { - // if the two aren't already identity constrained - // (whichever way around) or already identical (in - // case of rotated periodicity constraints), then - // enter the constraint. Otherwise there is nothing - // for us to do - bool enter_constraint = false; - if (!affine_constraints.is_constrained(dofs_1[j])) + const auto &constraint_entries = + *affine_constraints.get_constraint_entries(test_dof); + if (constraint_entries.size() == 1) { - if (dofs_2[i] != dofs_1[j]) - enter_constraint = true; + test_dof = constraint_entries[0].first; + cycle_factor *= constraint_entries[0].second; } - else // dofs_1[j] is constrained, is it identity or - // inverse constrained? + else { - const std::vector> - *constraint_entries = - affine_constraints.get_constraint_entries(dofs_1[j]); - if (constraint_entries->size() == 1 && - (*constraint_entries)[0].first == dofs_2[i]) - { - if (std::abs(std::abs((*constraint_entries)[0].second) - - 1) > eps) - { - // this pair of constraints means that - // both dofs have to be constrained to - // 0. - affine_constraints.add_line(dofs_2[i]); - } - } - else - { - // see if this would add an identity - // constraint cycle - types::global_dof_index new_dof = dofs_1[j]; - while (new_dof != dofs_2[i]) - if (affine_constraints.is_constrained(new_dof)) - { - const std::vector< - std::pair> - *constraint_entries = - affine_constraints.get_constraint_entries( - new_dof); - if (constraint_entries->size() == 1) - new_dof = (*constraint_entries)[0].first; - else - { - enter_constraint = true; - break; - } - } - else - { - enter_constraint = true; - break; - } - } + constraints_are_cyclic = false; + break; } + } - if (enter_constraint) - { - affine_constraints.add_line(dofs_2[i]); - affine_constraints.add_entry(dofs_2[i], dofs_1[j], factor); - } + // In case of a dependency cycle we, either + // - do nothing if cycle_factor == 1. In this case all degrees + // of freedom are already periodically constrained, + // - otherwise, force all dofs to zero (by setting dof_left to + // zero). The reasoning behind this is the fact that + // cycle_factor != 1 occurs in situations such as + // x1 == x2 and x2 == -1. * x1. This system is only solved by + // x_1 = x_2 = 0. + + if (constraints_are_cyclic) + { + if (std::abs(cycle_factor - 1.) > eps) + affine_constraints.add_line(dof_left); + } + else + { + affine_constraints.add_line(dof_left); + affine_constraints.add_entry(dof_left, dof_right, factor); } } /* for dofs_per_face */ } + // Internally used in make_periodicity_constraints. // // Build up a (possibly rotated) interpolation matrix that is used in