connected_components

Author: Teseo Schneider

src/connected_components.cpp

@@ -0,0 +1,53 @@
+#include <common.h>
+#include <npe.h>
+#include <typedefs.h>
+
+#include <igl/connected_components.h>
+
+const char *ds_connected_components = R"igl_Qu8mg5v7(
+
+Determine the connected components of a graph described by the input
+   adjacency matrix (similar to MATLAB's graphconncomp).
+
+Parameters
+----------
+
+A  #A by #A adjacency matrix (treated as describing an undirected graph)
+
+Returns
+-------
+Returns number of connected components
+C  #A list of component indices into [0,#K-1]
+K  #K list of sizes of each component
+
+See also
+--------
+
+
+Notes
+-----
+None
+
+Examples
+--------
+
+)igl_Qu8mg5v7";
+
+npe_function(connected_components)
+npe_doc(ds_connected_components)
+
+npe_arg(a, sparse_int, sparse_long, sparse_longlong)
+
+
+npe_begin_code()
+   assert_nonzero_rows(a, "A");
+   assert_cols_equals(a, a.rows(), "A");
+   Eigen::SparseMatrix<npe_Scalar_a> a_copy = a;
+   EigenDense<npe_Scalar_a> c;
+   EigenDense<npe_Scalar_a> k;
+   const int comps = igl::connected_components(a_copy, c, k);
+   return std::make_tuple(comps, npe::move(c), npe::move(k));
+
+npe_end_code()
+
+

tests/test_basic.py

@@ -2018,6 +2018,18 @@ def test_unique_edge_map(self):
         self.assertTrue(uE.shape[1] == 2)
         self.assertTrue(E.shape[0] == self.f1.shape[0]*3)
 
+    def test_connected_components(self):
+        a = igl.adjacency_matrix(self.f)
+        comps, c, k = igl.connected_components(a)
+
+        self.assertTrue(c.flags.c_contiguous)
+        self.assertTrue(k.flags.c_contiguous)
+
+        self.assertTrue(c.dtype == self.f1.dtype)
+        self.assertTrue(k.dtype == self.f1.dtype)
+
+        self.assertTrue(c.shape[0] == a.shape[0])
+
 
 if __name__ == '__main__':
     unittest.main()