eja: allow subalgebra_idempotent() to work in trivial EJAs.

[sage.d.git] / mjo / eja / eja_element.py

diff --git a/mjo/eja/eja_element.py b/mjo/eja/eja_element.py
index 575c2a4754ae261f284c53de4d423011c9bf5418..f44bee1c3f20d3040f0f77d8ff472b08c1bb5e9e 100644 (file)
--- a/mjo/eja/eja_element.py
+++ b/mjo/eja/eja_element.py
@@ -9,7 +9,7 @@ from sage.modules.with_basis.indexed_element import IndexedFreeModuleElement
 # TODO: make this unnecessary somehow.
 from sage.misc.lazy_import import lazy_import
 lazy_import('mjo.eja.eja_algebra', 'FiniteDimensionalEuclideanJordanAlgebra')
-lazy_import('mjo.eja.eja_subalgebra',
+lazy_import('mjo.eja.eja_element_subalgebra',
             'FiniteDimensionalEuclideanJordanElementSubalgebra')
 from mjo.eja.eja_operator import FiniteDimensionalEuclideanJordanAlgebraOperator
 from mjo.eja.eja_utils import _mat2vec
@@ -1270,10 +1270,13 @@ class FiniteDimensionalEuclideanJordanAlgebraElement(IndexedFreeModuleElement):
 
             sage: from mjo.eja.eja_algebra import random_eja
 
-        TESTS::
+        TESTS:
+
+        Ensure that we can find an idempotent in a non-trivial algebra
+        where there are non-nilpotent elements::
 
             sage: set_random_seed()
-            sage: J = random_eja()
+            sage: J = random_eja(nontrivial=True)
             sage: x = J.random_element()
             sage: while x.is_nilpotent():
             ....:     x = J.random_element()
@@ -1282,6 +1285,9 @@ class FiniteDimensionalEuclideanJordanAlgebraElement(IndexedFreeModuleElement):
             True
 
         """
+        if self.parent().is_trivial():
+            return self
+
         if self.is_nilpotent():
             raise ValueError("this only works with non-nilpotent elements!")