From: Michael Orlitzky <michael@orlitzky.com>
Date: Fri, 14 Nov 2025 01:21:10 +0000 (-0500)
Subject: mjo/cone/decomposition.py: handle trivial cones correctly
X-Git-Url: http://gitweb.michael.orlitzky.com/?a=commitdiff_plain;h=b8c1c05692272d64a3cece0f6bceffd75b23b4c3;p=sage.d.git

mjo/cone/decomposition.py: handle trivial cones correctly
---

diff --git a/mjo/cone/decomposition.py b/mjo/cone/decomposition.py
index a21b0ec..ca18b4d 100644
--- a/mjo/cone/decomposition.py
+++ b/mjo/cone/decomposition.py
@@ -160,11 +160,25 @@ def irreducible_factors(K):
         ValueError: cone must be strictly convex (AKA pointed) for its
         irreducible factors to be well-defined
 
+    Trivial cones are handled correctly::
+
+        sage: K = cones.trivial(0)
+        sage: irreducible_factors(K) == {K}
+        True
+        sage: K = cones.trivial(4)
+        sage: irreducible_factors(K) == {K}
+        True
+
     """
     if not K.is_strictly_convex():
         raise ValueError("cone must be strictly convex (AKA pointed) for"
                          " its irreducible factors to be well-defined")
 
+    if K.is_trivial():
+        # Trivial cones are valid inputs, but they have no generators
+        # so a special case is required.
+        return {K}
+
     V = K.ambient_vector_space()
 
     # Create a column matrix from the generators of K, and then