bindings for edges_to_path

src/edges_to_path.cpp

@@ -0,0 +1,56 @@
+#include "default_types.h"
+#include <igl/edges_to_path.h>
+#include <nanobind/nanobind.h>
+#include <nanobind/eigen/dense.h>
+#include <nanobind/stl/tuple.h>
+
+namespace nb = nanobind;
+using namespace nb::literals;
+
+namespace pyigl
+{
+    // Wrapper for igl::edges_to_path
+    auto edges_to_path(const nb::DRef<const Eigen::MatrixXI> &E)
+    {
+        // libigl's implementation internally maps to an int-backed buffer,
+        // so ensure the input scalar type is 32-bit int to avoid Map pointer mismatches.
+        using MatXI32 = Eigen::Matrix<int, Eigen::Dynamic, Eigen::Dynamic, Options>;
+        using VecXI32 = Eigen::Matrix<int, Eigen::Dynamic, 1>;
+
+        MatXI32 Ei = E.template cast<int>();
+        VecXI32 Ii, Ji, Ki;
+        igl::edges_to_path(Ei, Ii, Ji, Ki);
+
+        Eigen::VectorXI I = Ii.template cast<Integer>();
+        Eigen::VectorXI J = Ji.template cast<Integer>();
+        Eigen::VectorXI K = Ki.template cast<Integer>();
+        return std::make_tuple(I, J, K);
+    }
+}
+
+// Bind the wrapper to the Python module
+void bind_edges_to_path(nb::module_ &m)
+{
+    m.def(
+    "edges_to_path",
+    &pyigl::edges_to_path,
+    "E"_a,
+R"(Given a set of undirected, unique edges such that all form a
+single connected component with exactly 0 or 2 nodes with valence = 1,
+determine a path visiting all nodes.
+
+Parameters
+----------
+E : (#E, 2) int array
+    Undirected edges
+
+Returns
+-------
+I : (#E+1,) int array
+    Nodes in order tracing the chain (loop). If the output is a loop then I[0] == I[-1]
+J : (#I-1,) int array
+    Indices into E of edges tracing I
+K : (#I-1,) int array in {0,1}
+    Column indices so that I[i] == E[J[i], K[i]] for i < len(I)-1)"
+    );
+}

tests/test_all.py

@@ -164,7 +164,12 @@ def test_harmonic_integrated_from_laplacian_and_mass():
     M = igl.massmatrix(V, F, igl.MASSMATRIX_TYPE_VORONOI)
     Q = igl.harmonic_integrated_from_laplacian_and_mass(L, M, k=1)
     Q = igl.harmonic_integrated_from_laplacian_and_mass(L, M, k=2)
-
+
+def test_edges_to_path():
+    V,F = triangulated_square()
+    E, D, G = igl.boundary_facets(F)
+    _,_,_ = igl.edges_to_path(E)
+
 def test_tets():
     V,F,T = single_tet()
     F,J,K = igl.boundary_facets(T)