eja: drop redundant vector->superalgebra-element conversion.

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

diff --git a/mjo/eja/eja_subalgebra.py b/mjo/eja/eja_subalgebra.py
index d7bcf2c3a59638ef8a4176a7ae0dba2a422e6af2..cb9631df18b5a0749dda75855682c40a689cd5b3 100644 (file)
--- a/mjo/eja/eja_subalgebra.py
+++ b/mjo/eja/eja_subalgebra.py
@@ -56,6 +56,14 @@ class FiniteDimensionalEuclideanJordanSubalgebraElement(FiniteDimensionalEuclide
             f1
             sage: A(x).superalgebra_element()
             e0 + e1 + e2 + e3 + e4 + e5
+            sage: y = sum(A.gens())
+            sage: y
+            f0 + f1
+            sage: B = y.subalgebra_generated_by()
+            sage: B(y)
+            g1
+            sage: B(y).superalgebra_element()
+            f0 + f1
 
         TESTS:
 
@@ -70,10 +78,17 @@ class FiniteDimensionalEuclideanJordanSubalgebraElement(FiniteDimensionalEuclide
             sage: y = A.random_element()
             sage: A(y.superalgebra_element()) == y
             True
+            sage: B = y.subalgebra_generated_by()
+            sage: B(y).superalgebra_element() == y
+            True
 
         """
-        return self.parent().superalgebra().linear_combination(
-          zip(self.parent()._superalgebra_basis, self.to_vector()) )
+        W = self.parent().vector_space()
+        V = self.parent().superalgebra().vector_space()
+        A = W.basis_matrix().transpose()
+        W_coords = A*self.to_vector()
+        V_coords = V.coordinate_vector(W_coords)
+        return self.parent().superalgebra().from_vector(V_coords)
 
 
 
@@ -130,7 +145,7 @@ class FiniteDimensionalEuclideanJordanSubalgebra(FiniteDimensionalEuclideanJorda
         1
 
     """
-    def __init__(self, superalgebra, basis, category=None, check=True):
+    def __init__(self, superalgebra, basis, category=None, check_axioms=True):
         self._superalgebra = superalgebra
         V = self._superalgebra.vector_space()
         field = self._superalgebra.base_ring()
@@ -150,15 +165,17 @@ class FiniteDimensionalEuclideanJordanSubalgebra(FiniteDimensionalEuclideanJorda
             prefix = prefixen[0]
 
         basis_vectors = [ b.to_vector() for b in basis ]
-        superalgebra_basis = [ self._superalgebra.from_vector(b)
-                               for b in basis_vectors ]
 
+        # If our superalgebra is a subalgebra of something else, then
+        # these vectors won't have the right coordinates for
+        # V.span_of_basis() unless we use V.from_vector() on them.
         W = V.span_of_basis( V.from_vector(v) for v in basis_vectors )
-        n = len(superalgebra_basis)
+
+        n = len(basis)
         mult_table = [[W.zero() for i in range(n)] for j in range(n)]
         for i in range(n):
             for j in range(n):
-                product = superalgebra_basis[i]*superalgebra_basis[j]
+                product = basis[i]*basis[j]
                 # product.to_vector() might live in a vector subspace
                 # if our parent algebra is already a subalgebra. We
                 # use V.from_vector() to make it "the right size" in
@@ -166,13 +183,10 @@ class FiniteDimensionalEuclideanJordanSubalgebra(FiniteDimensionalEuclideanJorda
                 product_vector = V.from_vector(product.to_vector())
                 mult_table[i][j] = W.coordinate_vector(product_vector)
 
-        natural_basis = tuple( b.natural_representation()
-                               for b in superalgebra_basis )
+        natural_basis = tuple( b.natural_representation() for b in basis )
 
 
         self._vector_space = W
-        self._superalgebra_basis = superalgebra_basis
-
 
         fdeja = super(FiniteDimensionalEuclideanJordanSubalgebra, self)
         fdeja.__init__(field,
@@ -180,7 +194,8 @@ class FiniteDimensionalEuclideanJordanSubalgebra(FiniteDimensionalEuclideanJorda
                        prefix=prefix,
                        category=category,
                        natural_basis=natural_basis,
-                       check=check)
+                       check_field=False,
+                       check_axioms=check_axioms)