From bcf7f07092e70831a7d6924552de935ea1460d86 Mon Sep 17 00:00:00 2001
From: Jen Bradley <55467578+janbridley@users.noreply.github.com>
Date: Sat, 30 Sep 2023 11:35:26 -0400
Subject: [PATCH] Added `edge_lengths` property (#196)

* Added `edge_lengths` property

* Clarified documentation

* Updated changelog and credits

---------

Co-authored-by: Domagoj Fijan <50439291+DomFijan@users.noreply.github.com>
---
 ChangeLog.rst                |  7 +++++++
 Credits.rst                  |  2 +-
 coxeter/shapes/polyhedron.py | 13 ++++++++++++-
 tests/test_polyhedron.py     |  1 +
 4 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/ChangeLog.rst b/ChangeLog.rst
index e312f07a..349b06fa 100644
--- a/ChangeLog.rst
+++ b/ChangeLog.rst
@@ -1,6 +1,13 @@
 The format is based on `Keep a Changelog <http://keepachangelog.com/en/1.0.0/>`__.
 This project adheres to `Semantic Versioning <http://semver.org/spec/v2.0.0.html>`__.
 
+v0.x.x - 20xx-xx-xx
+
+Added
+~~~~~
+
+- New `edge_lengths` method.
+
 v0.7.0 - 2023-09-18
 -------------------
 
diff --git a/Credits.rst b/Credits.rst
index 97bc7beb..d6545066 100644
--- a/Credits.rst
+++ b/Credits.rst
@@ -112,7 +112,7 @@ Jen Bradley
 * Added shape families for Archimedean, Catalan, and Johnson solids.
 * Added shape family for prisms and antiprisms.
 * Added shape family for equilateral pyramids and dipyramids.
-* Added edges, edge_vectors, and num_edges methods.
+* Added edges, edge_vectors, edge_lengths, and num_edges methods.
 
 Domagoj Fijan
 * Rewrote point in polygon check to use NumPy vectorized operations.
diff --git a/coxeter/shapes/polyhedron.py b/coxeter/shapes/polyhedron.py
index 0f2dd6a9..4f0997cf 100644
--- a/coxeter/shapes/polyhedron.py
+++ b/coxeter/shapes/polyhedron.py
@@ -387,9 +387,20 @@ def edges(self):
 
     @property
     def edge_vectors(self):
-        """:class:`numpy.ndarray`: Get the polyhedron's edges as vectors."""
+        """:class:`numpy.ndarray`: Get the polyhedron's edges as vectors.
+
+        :code:`edge_vectors` are returned in the same order as in :attr:`edges`.
+        """
         return self.vertices[self.edges[:, 1]] - self.vertices[self.edges[:, 0]]
 
+    @property
+    def edge_lengths(self):
+        """:class:`numpy.ndarray`: Get the length of each edge of the polyhedron.
+
+        :code:`edge_lengths` are returned in the same order as in :attr:`edges`.
+        """
+        return np.linalg.norm(self.edge_vectors, axis=1)
+
     @property
     def num_edges(self):
         """int: Get the number of edges."""
diff --git a/tests/test_polyhedron.py b/tests/test_polyhedron.py
index 03028ef6..caa13600 100644
--- a/tests/test_polyhedron.py
+++ b/tests/test_polyhedron.py
@@ -393,6 +393,7 @@ def test_edge_lengths():
             poly.vertices[poly.edges[:, 1]] - poly.vertices[poly.edges[:, 0]], axis=1
         )
         assert np.allclose(veclens, edgelength)
+        assert np.allclose(poly.edge_lengths, edgelength)
         assert np.allclose(veclens, np.linalg.norm(poly.edge_vectors, axis=1))