Merge pull request #252 from higra/fix_empty_tree

fix empty tree creation from empty parent array
higra · Dec 5, 2022 · f58a301 · f58a301
2 parents 12e3230 + 9a69341
commit f58a301
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diff --git a/include/higra/structure/tree_graph.hpp b/include/higra/structure/tree_graph.hpp
@@ -255,6 +255,12 @@ namespace hg {
  private:
 
  void _init() {
+ if (_parents.size() == 0) {
+ _root = invalid_index;
+ _num_vertices = 0;
+ _num_leaves = 0;
+ return;
+ }
  hg_assert(_parents.shape().size() == 1, "parents must be a linear (1d) array");
  _num_vertices = _parents.size();
  _root = _num_vertices - 1;

diff --git a/test/cpp/structure/test_tree.cpp b/test/cpp/structure/test_tree.cpp
@@ -32,6 +32,10 @@ namespace tree {
  hg::tree t1;
  REQUIRE(hg::num_vertices(t1) == 0);
 
+ array_1d<index_t> p1{};
+ hg::tree t11(p1);
+ REQUIRE(hg::num_vertices(t11) == 0);
+
  array_1d<index_t> p2{5, 5, 6, 6, 6, 7, 7, 7};
  hg::tree t2(p2);
  REQUIRE(hg::num_vertices(t2) == 8);

diff --git a/test/python/test_structure/test_tree.py b/test/python/test_structure/test_tree.py
@@ -40,6 +40,15 @@ def test_size_tree(self):
  self.assertTrue(t.parent(4) == 6)
  self.assertTrue(np.all(t.parent((0, 5, 2, 3, 7)) == (5, 7, 6, 6, 7)))
 
+ def test_empty_tree(self):
+ t = hg.Tree([])
+
+ self.assertTrue(t.category() == hg.TreeCategory.PartitionTree)
+ self.assertTrue(t.root() == -1)
+ self.assertTrue(t.num_vertices() == 0)
+ self.assertTrue(t.num_edges() == 0)
+ self.assertTrue(t.num_leaves() == 0)
+
  def test_dynamic_attributes(self):
  t = TestTree.get_tree()
  t.new_attribute = 42