From: Michael Orlitzky <michael@orlitzky.com>
Date: Mon, 9 Nov 2020 12:44:59 +0000 (-0500)
Subject: eja: use fuzzy equality test with inexact base rings.
X-Git-Url: http://gitweb.michael.orlitzky.com/?a=commitdiff_plain;h=ef91dedb7fecddd4c0a5472e501188739b3d3d88;p=sage.d.git

eja: use fuzzy equality test with inexact base rings.
---

diff --git a/mjo/eja/eja_algebra.py b/mjo/eja/eja_algebra.py
index 3846b83..7f7b1f9 100644
--- a/mjo/eja/eja_algebra.py
+++ b/mjo/eja/eja_algebra.py
@@ -296,14 +296,26 @@ class FiniteDimensionalEuclideanJordanAlgebra(CombinatorialFreeModule):
         this algebra was constructed with ``check=False`` and passed
         an invalid multiplication table.
         """
+
+        # Used to check whether or not something is zero in an inexact
+        # ring. This number is sufficient to allow the construction of
+        # QuaternionHermitianEJA(2, RDF) with check=True.
+        epsilon = 1e-16
+
         for i in range(self.dimension()):
             for j in range(self.dimension()):
                 for k in range(self.dimension()):
                     x = self.monomial(i)
                     y = self.monomial(j)
                     z = self.monomial(k)
-                    if (x*y).inner_product(z) != x.inner_product(y*z):
-                        return False
+                    diff = (x*y).inner_product(z) - x.inner_product(y*z)
+
+                    if self.base_ring().is_exact():
+                        if diff != 0:
+                            return False
+                    else:
+                        if diff.abs() > epsilon:
+                            return False
 
         return True