Commit 5dd0408c authored by Dennis Gläser's avatar Dennis Gläser
Browse files

[examples] add example2

parent dd8278e9
frackit_add_application(NAME example2
LABELS examples)
#include <random>
#include <iostream>
#include <frackit/common/id.hh>
#include <frackit/io/gmshwriter.hh>
#include <frackit/sampling/makeuniformpointsampler.hh>
#include <frackit/sampling/quadrilateralsampler.hh>
#include <frackit/sampling/status.hh>
#include <frackit/geometry/quadrilateral.hh>
#include <frackit/geometry/box.hh>
#include <frackit/geometry/cylinder.hh>
#include <frackit/magnitude/containedmagnitude.hh>
#include <frackit/entitynetwork/constraints.hh>
#include <frackit/entitynetwork/networkbuilder.hh>
//! create a network of 3d quadrilaterals contained in a cylinder
int main()
using namespace Frackit;
// We use the same samplers for quadrilaterals as in example 1.
// Therefore, we do not repeat the comments here. For more details
// please see the main file of example1. We will only add comments
// here in those places that deviate from the first example.
static constexpr int worldDimension = 3;
using ctype = double;
using Quad = Quadrilateral<ctype, worldDimension>;
// In this example we consider a cylindrical domain
Cylinder<ctype> domain(/*radius*/0.5, /*height*/1.0);
// However, we still sample the quadrilateral sample points
// within the unit cube (a sampler on cylinders is also available)
// Note that we shift the unit cube to have the origin in
// the center of the bottom boundary
Box<ctype> unitCube(-0.5, -0.5, 0.0, 0.5, 0.5, 1.0);
using QuadSampler = QuadrilateralSampler<worldDimension>;
using Distro = std::normal_distribution<ctype>;
QuadSampler quadSampler1(makeUniformPointSampler(unitCube),
Distro(toRadians(45.0), toRadians(5.0)),
Distro(toRadians(90.0), toRadians(5.0)),
Distro(0.5, 0.1),
QuadSampler quadSampler2(makeUniformPointSampler(unitCube),
Distro(toRadians(0.0), toRadians(5.0)),
Distro(toRadians(0.0), toRadians(5.0)),
Distro(0.5, 0.1),
EntityNetworkConstraints constraintsOnSelf;
auto constraintsOnOther = constraintsOnSelf;
// We can now also enforce constraints w.r.t. the domain boundary
auto constraintsOnBoundary = constraintsOnSelf;
std::vector<Quad> entitySet1;
std::vector<Quad> entitySet2;
const Id idSet1(1);
const Id idSet2(2);
SamplingStatus status;
status.setTargetCount(idSet1, 15);
status.setTargetCount(idSet2, 15);
bool sampleIntoSet1 = true;
std::cout << "\n --- Start entity sampling ---\n" << std::endl;
while (!status.finished())
auto quad = sampleIntoSet1 ? quadSampler1() : quadSampler2();
auto& entitySet = sampleIntoSet1 ? entitySet1 : entitySet2;
const auto& otherEntitySet = sampleIntoSet1 ? entitySet2 : entitySet1;
if (!constraintsOnSelf.evaluate(entitySet, quad))
{ status.increaseRejectedCounter(); continue; }
if (!constraintsOnOther.evaluate(otherEntitySet, quad))
{ status.increaseRejectedCounter(); continue; }
// we want to enforce constraints also w.r.t. to the cylinder boundary
if (!constraintsOnBoundary.evaluate(domain.topFace(), quad))
{ status.increaseRejectedCounter(); continue; }
if (!constraintsOnBoundary.evaluate(domain.bottomFace(), quad))
{ status.increaseRejectedCounter(); continue; }
if (!constraintsOnBoundary.evaluate(domain.lateralFace(), quad))
{ status.increaseRejectedCounter(); continue; }
// we also want to neglect quadrilaterals of which only
// small fragments remain after confining them to the
// domain. This computes the area of the quad that is
// inside the domain
const auto containedArea = computeContainedMagnitude(quad, domain);
// reject if this is too small (< 0.01 m^2)
if (containedArea < 0.01)
{ status.increaseRejectedCounter(); continue; }
status.increaseCounter(sampleIntoSet1 ? idSet1 : idSet2);
sampleIntoSet1 = !sampleIntoSet1;
std::cout << "\n --- Finished entity sampling ---\n" << std::endl;
// We can now create a contained entity network from the two sets,
// which has information on both the entities and the domain.
ContainedEntityNetworkBuilder builder;
// define the domain (single sub-domain) and give it a unique id
builder.addConfiningSubDomain(domain, Id(1));
// define entities to be embedded in this domain
builder.addSubDomainEntities(entitySet1, Id(1));
builder.addSubDomainEntities(entitySet2, Id(1));
const auto network =;
// This can be written out in Gmsh (.geo) format to be
// meshed by a three-dimensional mesh that is conforming
// to the two-dimensional quadrilaterals
std::cout << "\n --- Writing .geo file ---\n" << std::endl;
GmshWriter writer(network);
writer.write("network", // filename of the .geo files (will add extension .geo automatically)
0.1, // element size to be used on the quadrilaterals
0.2); // element size to be used in the domain away from the quadrilaterals
std::cout << "\n --- Finished writing .geo file ---\n" << std::endl;
return 0;
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment