From a92866dcb25a653476daf1d1877fc34796d006f1 Mon Sep 17 00:00:00 2001
From: Joe Wallwork <jw2423@cam.ac.uk>
Date: Wed, 12 Jun 2024 13:39:46 +0100
Subject: [PATCH] Raise error if points are identical

---
 maths.py | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/maths.py b/maths.py
index 6bd8cd5..5ea2e16 100644
--- a/maths.py
+++ b/maths.py
@@ -1,3 +1,6 @@
+import numpy as np
+
+
 def equation_of_line(a, b):
     """
     Determine the equation of the line passing through two points.
@@ -6,6 +9,8 @@ def equation_of_line(a, b):
     :arg b: the second point the line passes through
     :return: function of two variables defining the line
     """
+    if np.allclose(a, b):
+        raise ValueError("Cannot determine a unique line through {a} and {b}.")
     x0, y0 = a
     x1, y1 = b