/**
* Backtracking graph coloring routines
*/
bool
colorGraph(const PolycrystalICTools::AdjacencyMatrix<Real> & adjacency_matrix,
std::vector<unsigned int> & colors,
unsigned int n_vertices,
unsigned int n_colors,
unsigned int vertex)
{
// Base case: All grains are assigned
if (vertex == n_vertices)
return true;
// Consider this grain and try different ops
for (unsigned int color_idx = 0; color_idx < n_colors; ++color_idx)
{
// We'll try to spread these colors around a bit rather than
// packing them all on the first few colors if we have several colors.
unsigned int color = (vertex + color_idx) % n_colors;
if (isGraphValid(adjacency_matrix, colors, n_vertices, vertex, color))
{
colors[vertex] = color;
if (colorGraph(adjacency_matrix, colors, n_vertices, n_colors, vertex + 1))
return true;
// Backtrack...
colors[vertex] = GraphColoring::INVALID_COLOR;
}
}
return false;
}
std::vector<unsigned int>
PolycrystalICTools::assignOpsToGrains(AdjacencyMatrix<Real> & adjacency_matrix,
unsigned int n_grains,
unsigned int n_ops,
const MooseEnum & coloring_algorithm)
{
Moose::perf_log.push("assignOpsToGrains()", "PolycrystalICTools");
std::vector<unsigned int> grain_to_op(n_grains, GraphColoring::INVALID_COLOR);
// Use a simple backtracking coloring algorithm
if (coloring_algorithm == "bt")
{
if (!colorGraph(adjacency_matrix, grain_to_op, n_grains, n_ops, 0))
mooseError(
"Unable to find a valid Grain to op configuration, do you have enough op variables?");
}
else // PETSc Coloring algorithms
{
#ifdef LIBMESH_HAVE_PETSC
const std::string & ca_str = coloring_algorithm;
Real * am_data = adjacency_matrix.rawDataPtr();
Moose::PetscSupport::colorAdjacencyMatrix(
am_data, n_grains, n_ops, grain_to_op, ca_str.c_str());
#else
mooseError("Selected coloring algorithm requires PETSc");
#endif
}
Moose::perf_log.pop("assignOpsToGrains()", "PolycrystalICTools");
return grain_to_op;
}
bool
PolycrystalUserObjectBase::colorGraph(unsigned int vertex)
{
// Base case: All grains are assigned
if (vertex == _feature_count)
return true;
// Consider this grain and try different ops
for (unsigned int color_idx = 0; color_idx < _op_num; ++color_idx)
{
// We'll try to spread these colors around a bit rather than
// packing them all on the first few colors if we have several colors.
unsigned int color = (vertex + color_idx) % _op_num;
if (isGraphValid(vertex, color))
{
_grain_to_op[vertex] = color;
if (colorGraph(vertex + 1))
return true;
// Backtrack...
_grain_to_op[vertex] = PolycrystalUserObjectBase::INVALID_COLOR;
}
}
return false;
}
void
PolycrystalUserObjectBase::assignOpsToGrains()
{
mooseAssert(_is_master, "This routine should only be called on the master rank");
// Moose::perf_log.push("assignOpsToGrains()", "PolycrystalICTools");
//
// Use a simple backtracking coloring algorithm
if (_coloring_algorithm == "bt")
{
if (!colorGraph(0))
mooseError("Unable to find a valid grain to op coloring, do you have enough op variables?");
}
else // PETSc Coloring algorithms
{
#ifdef LIBMESH_HAVE_PETSC
const std::string & ca_str = _coloring_algorithm;
Real * am_data = _adjacency_matrix->get_values().data();
Moose::PetscSupport::colorAdjacencyMatrix(
am_data, _feature_count, _vars.size(), _grain_to_op, ca_str.c_str());
#else
mooseError("Selected coloring algorithm requires PETSc");
#endif
}
// Moose::perf_log.pop("assignOpsToGrains()", "PolycrystalICTools");
}
void
PolycrystalUserObjectBase::assignOpsToGrains()
{
mooseAssert(_is_master, "This routine should only be called on the master rank");
Moose::perf_log.push("assignOpsToGrains()", "PolycrystalICTools");
// Use a simple backtracking coloring algorithm
if (_coloring_algorithm == "bt")
{
paramInfo("coloring_algorithm",
"The backtracking algorithm has exponential complexity. If you are using very few "
"order parameters, or you have several hundred grains or more, you should use one of "
"the PETSc coloring algorithms such as \"jp\".");
if (!colorGraph(0))
paramError("op_num",
"Unable to find a valid grain to op coloring, Make sure you have created enough "
"variables to hold a valid polycrystal initial condition (no grains represented "
"by the same variable should be allowed to touch, ~8 for 2D, ~25 for 3D)?");
}
else // PETSc Coloring algorithms
{
#ifdef LIBMESH_HAVE_PETSC
const std::string & ca_str = _coloring_algorithm;
Real * am_data = _adjacency_matrix->get_values().data();
try
{
Moose::PetscSupport::colorAdjacencyMatrix(
am_data, _feature_count, _vars.size(), _grain_to_op, ca_str.c_str());
}
catch (std::runtime_error & e)
{
paramError("op_num",
"Unable to find a valid grain to op coloring, Make sure you have created enough "
"variables to hold a valid polycrystal initial condition (no grains represented "
"by the same variable should be allowed to touch, ~8 for 2D, ~25 for 3D)?");
}
#else
mooseError("Selected coloring algorithm requires PETSc");
#endif
}
Moose::perf_log.pop("assignOpsToGrains()", "PolycrystalICTools");
}