Added PolyLineMeshGenerator

Refs idaholab#20192

framework/include/meshgenerators/PolyLineMeshGenerator.h

@@ -0,0 +1,35 @@
+//* This file is part of the MOOSE framework
+//* https://www.mooseframework.org
+//*
+//* All rights reserved, see COPYRIGHT for full restrictions
+//* https://github.com/idaholab/moose/blob/master/COPYRIGHT
+//*
+//* Licensed under LGPL 2.1, please see LICENSE for details
+//* https://www.gnu.org/licenses/lgpl-2.1.html
+
+#pragma once
+
+#include "MeshGenerator.h"
+
+/**
+ * Generates a polyline (open ended or looped) of Edge elements
+ * through a series of nodal locations and other input parameters.
+ */
+class PolyLineMeshGenerator : public MeshGenerator
+{
+public:
+  static InputParameters validParams();
+
+  PolyLineMeshGenerator(const InputParameters & parameters);
+
+  std::unique_ptr<MeshBase> generate() override;
+
+protected:
+  std::vector<Point> _points;
+
+  bool _loop;
+
+  boundary_id_type _bcid0, _bcid1;
+
+  unsigned int _nebp;
+};

framework/src/meshgenerators/PolyLineMeshGenerator.C

@@ -0,0 +1,106 @@
+//* This file is part of the MOOSE framework
+//* https://www.mooseframework.org
+//*
+//* All rights reserved, see COPYRIGHT for full restrictions
+//* https://github.com/idaholab/moose/blob/master/COPYRIGHT
+//*
+//* Licensed under LGPL 2.1, please see LICENSE for details
+//* https://www.gnu.org/licenses/lgpl-2.1.html
+
+#include "PolyLineMeshGenerator.h"
+
+#include "CastUniquePointer.h"
+#include "MooseUtils.h"
+
+#include "libmesh/elem.h"
+#include "libmesh/int_range.h"
+#include "libmesh/unstructured_mesh.h"
+
+registerMooseObject("MooseApp", PolyLineMeshGenerator);
+
+InputParameters
+PolyLineMeshGenerator::validParams()
+{
+  InputParameters params = MeshGenerator::validParams();
+
+  params.addParam<std::vector<Point>>("points", "The points defining the polyline, in order");
+
+  params.addParam<bool>("loop", false, "Whether edges should form a closed loop");
+
+  params.addParam<boundary_id_type>("bcid0", 0, "Boundary id for (non-looped) polyline start");
+
+  params.addParam<boundary_id_type>("bcid1", 1, "Boundary id for (non-looped) polyline end");
+
+  params.addParam<unsigned int>(
+      "num_edges_between_points", 1, "How many Edge elements to build between each point pair");
+
+  return params;
+}
+
+PolyLineMeshGenerator::PolyLineMeshGenerator(const InputParameters & parameters)
+  : MeshGenerator(parameters),
+    _points(getParam<std::vector<Point>>("points")),
+    _loop(getParam<bool>("loop")),
+    _bcid0(getParam<boundary_id_type>("bcid0")),
+    _bcid1(getParam<boundary_id_type>("bcid1")),
+    _nebp(getParam<unsigned int>("num_edges_between_points"))
+{
+}
+
+std::unique_ptr<MeshBase>
+PolyLineMeshGenerator::generate()
+{
+  auto uptr_mesh = buildMeshBaseObject();
+  MeshBase & mesh = *uptr_mesh;
+
+  if (_points.size() < 2)
+    paramError("points", "At least 2 points are needed to define a polyline");
+
+  if (_loop && _points.size() < 3)
+    paramError("points", "At least 3 points are needed to define a polygon");
+
+  const auto n_points = _points.size();
+  for (auto i : make_range(n_points))
+    {
+      Point p = _points[i];
+      mesh.add_point(p, i * _nebp);
+      if (_nebp > 1)
+      {
+        if (!_loop && (i + 1) == n_points)
+          break;
+
+        const auto ip1 = (i + 1) % n_points;
+        const Point pvec = (_points[ip1] - p) / _nebp;
+
+        for (auto j : make_range(1u, _nebp))
+        {
+          p += pvec;
+          mesh.add_point(p, i * _nebp + j);
+        }
+      }
+    }
+
+    const auto n_segments = _loop ? n_points : (n_points - 1);
+    const auto n_elem = n_segments * _nebp;
+    const auto max_nodes = n_points * _nebp;
+    for (auto i : make_range(n_elem))
+    {
+      const auto ip1 = (i + 1) % max_nodes;
+      auto elem = Elem::build(EDGE2);
+      elem->set_node(0) = mesh.node_ptr(i);
+      elem->set_node(1) = mesh.node_ptr(ip1);
+      elem->set_id() = i;
+      mesh.add_elem(std::move(elem));
+    }
+
+  if (!_loop)
+  {
+    BoundaryInfo & bi = mesh.get_boundary_info();
+    bi.add_side(mesh.elem_ptr(0), 0, _bcid0);
+    bi.add_side(mesh.elem_ptr(n_elem - 1), 1, _bcid1);
+  }
+
+  mesh.prepare_for_use();
+
+  return uptr_mesh;
+}