octonions: rename octonions() accessor to entry_algebra().

This entire class can be made more generic. Here's phase one.

diff --git a/mjo/octonions.py b/mjo/octonions.py
index c2b829f98b9b49dbe078172a3669f0cb8b6406e4..f786fcf1228e62f605876c04a2003614d5015e64 100644 (file)
--- a/mjo/octonions.py
+++ b/mjo/octonions.py
@@ -376,7 +376,7 @@ class OctonionMatrix(IndexedFreeModuleElement):
             [[e0 + 2*e3, 0, 0], [0, 0, 0], [0, 0, 0]]
 
         """
-        zero = self.parent().octonions().zero()
+        zero = self.parent().entry_algebra().zero()
         l = [[zero for j in range(self.ncols())] for i in range(self.nrows())]
         for (k,v) in self.monomial_coefficients().items():
             (i,j,e) = k
@@ -464,7 +464,7 @@ class OctonionMatrix(IndexedFreeModuleElement):
             3*e0
 
         """
-        zero = self.parent().octonions().zero()
+        zero = self.parent().entry_algebra().zero()
         return sum( (self[i,i] for i in range(self.nrows())), zero )
 
     def matrix_space(self):
@@ -530,8 +530,8 @@ class OctonionMatrixAlgebra(CombinatorialFreeModule):
 
         I = FiniteEnumeratedSet(range(n))
         J = FiniteEnumeratedSet(range(n))
-        self._octonions = Octonions(field=field)
-        entry_basis = self._octonions.gens()
+        self._entry_algebra = Octonions(field=field)
+        entry_basis = self._entry_algebra.gens()
 
         basis_indices = cartesian_product([I,J,entry_basis])
         super().__init__(field,
@@ -545,11 +545,11 @@ class OctonionMatrixAlgebra(CombinatorialFreeModule):
                 " over the scalar ring %s" %
                 (self.nrows(), self.ncols(), self.base_ring()) )
 
-    def octonions(self):
+    def entry_algebra(self):
         r"""
-        Return the Octonion algebra that our elements' entries come from.
+        Return the algebra that our elements' entries come from.
         """
-        return self._octonions
+        return self._entry_algebra
 
     def nrows(self):
         return self._nrows
@@ -578,7 +578,7 @@ class OctonionMatrixAlgebra(CombinatorialFreeModule):
             True
 
         """
-        return sum( (self.monomial((i,i,self._octonions.one()))
+        return sum( (self.monomial((i,i,self.entry_algebra().one()))
                      for i in range(self.nrows()) ),
                     self.zero() )
 
@@ -618,7 +618,7 @@ class OctonionMatrixAlgebra(CombinatorialFreeModule):
             # given octonion algebra to ours. Otherwise we can fail
             # to convert an element of (for example) Octonions(QQ)
             # to Octonions(AA).
-            return self.octonions().from_vector(e_ij.to_vector())
+            return self.entry_algebra().from_vector(e_ij.to_vector())
 
         return sum( (self.monomial( (i,j, convert(entries[i][j])) )
                      for i in range(nrows)