From 37a141533397568e7070c734e21ef9c4dc85d132 Mon Sep 17 00:00:00 2001
From: Vincent Rouvreau <vincent.rouvreau@inria.fr>
Date: Thu, 10 Feb 2022 16:16:14 +0100
Subject: Add SimplexTree copy method and its test

---
 src/python/gudhi/simplex_tree.pxd    |  1 +
 src/python/gudhi/simplex_tree.pyx    | 14 ++++++++++++++
 src/python/test/test_simplex_tree.py | 19 ++++++++++++++++++-
 3 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/src/python/gudhi/simplex_tree.pxd b/src/python/gudhi/simplex_tree.pxd
index 006a24ed..92139db4 100644
--- a/src/python/gudhi/simplex_tree.pxd
+++ b/src/python/gudhi/simplex_tree.pxd
@@ -45,6 +45,7 @@ cdef extern from "Simplex_tree_interface.h" namespace "Gudhi":
 
     cdef cppclass Simplex_tree_interface_full_featured "Gudhi::Simplex_tree_interface<Gudhi::Simplex_tree_options_full_featured>":
         Simplex_tree_interface_full_featured() nogil
+        Simplex_tree_interface_full_featured(Simplex_tree_interface_full_featured&) nogil
         double simplex_filtration(vector[int] simplex) nogil
         void assign_simplex_filtration(vector[int] simplex, double filtration) nogil
         void initialize_filtration() nogil
diff --git a/src/python/gudhi/simplex_tree.pyx b/src/python/gudhi/simplex_tree.pyx
index c3720936..6b3116a4 100644
--- a/src/python/gudhi/simplex_tree.pyx
+++ b/src/python/gudhi/simplex_tree.pyx
@@ -63,6 +63,20 @@ cdef class SimplexTree:
          """
         return self.pcohptr != NULL
 
+    def copy(self):
+        """ 
+        :returns: A simplex tree that is a deep copy itself.
+        :rtype: SimplexTree
+        """
+        stree = SimplexTree()
+        cdef Simplex_tree_interface_full_featured* stree_ptr
+        cdef Simplex_tree_interface_full_featured* self_ptr=self.get_ptr()
+        with nogil:
+            stree_ptr = new Simplex_tree_interface_full_featured(dereference(self_ptr))
+
+        stree.thisptr = <intptr_t>(stree_ptr)
+        return stree
+
     def filtration(self, simplex):
         """This function returns the filtration value for a given N-simplex in
         this simplicial complex, or +infinity if it is not in the complex.
diff --git a/src/python/test/test_simplex_tree.py b/src/python/test/test_simplex_tree.py
index 31c46213..dac45288 100755
--- a/src/python/test/test_simplex_tree.py
+++ b/src/python/test/test_simplex_tree.py
@@ -447,4 +447,21 @@ def test_persistence_intervals_in_dimension():
     assert np.array_equal(H2, np.array([[ 0., float("inf")]]))
     # Test empty case
     assert st.persistence_intervals_in_dimension(3).shape == (0, 2)
-    
\ No newline at end of file
+
+def test_simplex_tree_copy():
+    st = SimplexTree()
+    st .insert([1,2,3], 0.)
+    a = st.copy()
+    # TODO(VR): when #463 is merged, replace with
+    # assert a == st
+    assert a.num_vertices() == st.num_vertices()
+    assert a.num_simplices() == st.num_simplices()
+    st_filt_list = list(st.get_filtration())
+    assert list(a.get_filtration()) == st_filt_list
+
+    a.remove_maximal_simplex([1, 2, 3])
+    a_filt_list = list(a.get_filtration())
+    assert len(a_filt_list) < len(st_filt_list)
+
+    for a_splx in a_filt_list:
+        assert a_splx in st_filt_list
-- 
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