properly rename cell_size -> edge_size for 2D

Author: nschloe

README.md

@@ -36,7 +36,7 @@ import pygalmesh
 points = numpy.array([[0.0, 0.0], [1.0, 0.0], [1.0, 1.0], [0.0, 1.0]])
 constraints = [[0, 1], [1, 2], [2, 3], [3, 0]]
 
-mesh = pygalmesh.generate_2d(points, constraints, cell_size=1.0e-1, num_lloyd_steps=10)
+mesh = pygalmesh.generate_2d(points, constraints, edge_size=1.0e-1, num_lloyd_steps=10)
 # mesh.points, mesh.cells
 ```
 The quality of the mesh isn't very good, but can be improved with

src/generate_2d.cpp

@@ -30,9 +30,9 @@ generate_2d(
   // for what the bounds mean. Spoiler:
   // B = circumradius / shortest_edge,
   //   relates to the smallest angle via sin(alpha_min) = 1 / (2B)
-  // cell_size is "size",
+  // edge_size S: "all segments of all triangles must be shorter than a bound S."
   const double max_circumradius_shortest_edge_ratio,
-  const double cell_size,
+  const double edge_size,
   const int num_lloyd_steps
 )
 {
@@ -53,7 +53,7 @@ generate_2d(
       cdt,
       Criteria(
         0.25 / (max_circumradius_shortest_edge_ratio * max_circumradius_shortest_edge_ratio),
-        cell_size
+        edge_size
        )
       );
 

src/generate_2d.hpp

@@ -2,6 +2,7 @@
 #define GENERATE_2D_HPP
 
 #include <memory>
+#include <pthread.h>
 #include <vector>
 
 namespace pygalmesh {
@@ -11,7 +12,11 @@ generate_2d(
   const std::vector<std::array<double, 2>> & points,
   const std::vector<std::array<int, 2>> & constraints,
   const double max_circumradius_shortest_edge_ratio,
-  const double cell_size,
+  // https://github.com/CGAL/cgal/issues/5061#issuecomment-705520984
+  // the "default" size criterion for a triangle in the 2D mesh generator refers to its
+  // edges lengths. In the output mesh, all segments of all triangles must be shorter
+  // than the given bound.pthread_mutexattr_getprotocol
+  const double edge_size,
   const int num_lloyd_steps
 );
 

src/pybind11.cpp

@@ -262,7 +262,7 @@ PYBIND11_MODULE(_pygalmesh, m) {
         py::arg("points"),
         py::arg("constraints"),
         py::arg("max_circumradius_shortest_edge_ratio") = 1.41421356237,
-        py::arg("cell_size") = 0.0,
+        py::arg("edge_size") = 0.0,
         py::arg("num_lloyd_steps") = 0
         );
     m.def(

test/test_2d.py

@@ -8,7 +8,7 @@ def test_2d():
     constraints = [[0, 1], [1, 2], [2, 3], [3, 0]]
 
     mesh = pygalmesh.generate_2d(
-        points, constraints, cell_size=1.0e-1, num_lloyd_steps=10
+        points, constraints, edge_size=1.0e-1, num_lloyd_steps=10
     )
 
     assert mesh.points.shape == (276, 2)