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// -----------------------------------------------------------------------------
//
// Gmsh C++ extended tutorial 4
//
// Post-processing data import: model-based
//
// -----------------------------------------------------------------------------
#include <set>
#include <gmsh.h>
int main(int argc, char **argv)
{
gmsh::initialize(argc, argv);
// Contrary to list-based view (see `x3.cpp'), model-based views are based on
// one or more meshes. Compared to list-based views, they are thus linked to
// one model (per step). Post-processing data stored in MSH files create such
// model-based views.
// Let's create a first model-based view using a simple mesh constructed by
// hand. We create a model with a discrete surface
gmsh::model::add("simple model");
int surf = gmsh::model::addDiscreteEntity(2);
// We add 4 nodes and 2 3-node triangles (element type "2")
gmsh::model::mesh::addNodes(2, surf, {1, 2, 3, 4},
{0., 0., 0., 1., 0., 0., 1., 1., 0., 0., 1., 0.});
gmsh::model::mesh::addElementsByType(surf, 2, {1, 2}, {1, 2, 3, 1, 3, 4});
// We can now create a new model-based view, to which we add 10 steps of
// node-based data:
int t1 = gmsh::view::add("Continuous");
for(int step = 0; step < 10; step++) {
gmsh::view::addHomogeneousModelData(
t1, step, "simple model", "NodeData", {1, 2, 3, 4}, // tags of nodes
{10., 10., 12. + step, 13. + step}); // data, per node
}
// Besided node-based data, which result in continuous fields, one can also
// add general discontinous fields defined at the nodes of each element, using
// "ElementNodeData":
int t2 = gmsh::view::add("Discontinuous");
for(int step = 0; step < 10; step++) {
gmsh::view::addHomogeneousModelData(
t2, step, "simple model", "ElementNodeData", {1, 2}, // tags of elements
{10., 10., 12. + step, 14., 15., 13. + step}); // data per element nodes
}
// Constant per element datasets can also be created using "ElementData". Note
// that a more general function `addModelData' to add data for hybrid meshes
// (when data is not homogeneous, i.e. when the number of nodes changes
// between elements) is also available.
// Each step of a model-based view can be defined on a different model,
// i.e. on a different mesh. Let's define a second model and mesh it
gmsh::model::add("another model");
gmsh::model::occ::addBox(0, 0, 0, 1, 1, 1);
gmsh::model::occ::synchronize();
gmsh::model::mesh::generate(3);
// We can add other steps to view "t" based on this new mesh:
std::vector<std::size_t> nodes;
std::vector<double> coord, coordParam;
gmsh::model::mesh::getNodes(nodes, coord, coordParam);
for(int step = 11; step < 20; step++) {
std::vector<double> val;
for(std::size_t i = 0; i < coord.size(); i += 3)
val.push_back(step * coord[i]);
gmsh::view::addHomogeneousModelData(t1, step, "another model", "NodeData",
nodes, val);
}
// This feature allows to create seamless animations for time-dependent
// datasets on deforming or remeshed models.
// High-order node-based datasets are supported without needing to supply the
// interpolation matrices (iso-parametric Lagrange elements). Arbitrary
// high-order datasets can be specified as "ElementNodeData", with the
// interpolation matrices specified in the same as as for list-based views
// (see `x3.cpp').
// Model-based views can be saved to disk using `gmsh::view::write()'; note
// that saving a view based on multiple meshes (like the view `t1') will
// automatically create several files. If the `PostProcessing.SaveMesh' option
// is not set, `gmsh::view::write()' will only save the view data, without the
// mesh (which could be saved independently with `gmsh::write()').
gmsh::view::write(t1, "x4_t1.msh");
gmsh::view::write(t2, "x4_t2.msh");
// Launch the GUI to see the results:
std::set<std::string> args(argv, argv + argc);
if(!args.count("-nopopup")) gmsh::fltk::run();
gmsh::finalize();
return 0;
}
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