matrix_algebra: factor out Hurwitz subclass.

[sage.d.git] / mjo / octonions.py

diff --git a/mjo/octonions.py b/mjo/octonions.py
index 073765ccf1ef934ab6d9f6fc59435384bf832f36..289c46a69b075f22409b69f827d7c8efbfee375d 100644 (file)
--- a/mjo/octonions.py
+++ b/mjo/octonions.py
@@ -141,6 +141,11 @@ class Octonion(IndexedFreeModuleElement):
         """
         return self._norm_squared().sqrt()
 
+    # The absolute value notation is typically used for complex numbers...
+    # and norm() isn't supported in AA, so this lets us use abs() in all
+    # of the division algebras we need.
+    abs = norm
+
     def inverse(self):
         r"""
         Return the inverse of this element if it exists.
@@ -369,8 +374,8 @@ class OctonionMatrixAlgebra(MatrixAlgebra):
         sage: O = Octonions(QQ)
         sage: e0,e1,e2,e3,e4,e5,e6,e7 = O.gens()
         sage: MS = OctonionMatrixAlgebra(2)
-        sage: MS.from_list([ [e0+e4, e1+e5],
-        ....:                [e2-e6, e3-e7] ])
+        sage: MS([ [e0+e4, e1+e5],
+        ....:      [e2-e6, e3-e7] ])
         +---------+---------+
         | e0 + e4 | e1 + e5 |
         +---------+---------+