X-Git-Url: http://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=mjo%2Feja%2FTODO;h=6223bff9331ba3144cbfdd8fbdd8fe616139a230;hb=b259821a73cb75a6d5a81d13256802be023b0fa9;hp=103e8d1017eb5589b6bc5eedcc91655eb13d8c0d;hpb=98bb214e8175eb3526d248c69b3fafe8ab694705;p=sage.d.git

diff --git a/mjo/eja/TODO b/mjo/eja/TODO
index 103e8d1..6223bff 100644
--- a/mjo/eja/TODO
+++ b/mjo/eja/TODO
@@ -1,19 +1,15 @@
-1. Finish CartesianProductEJA: add random_instance() method and
-   optimize. I guess I should create a separate class hierarchy for
-   Cartesian products of RationalBasisEJA? That way we get fast
-   charpoly and random_instance() defined...
+1. Add references and start citing them.
 
-2. Add references and start citing them.
+2. Profile (and fix?) any remaining slow operations.
 
-3. Implement the octonion simple EJA.
+3. When we take a Cartesian product involving a trivial algebra, we
+   could easily cache the identity and charpoly coefficients using
+   the nontrivial factor. On the other hand, it's nice that we can
+   test out some alternate code paths...
 
-4. Pre-cache charpoly for some small algebras?
+4. Can we hit "x" with the deortho matrix and delegate to the
+   _rational_algebra to speed up minimal_polynomial?
 
-RealSymmetricEJA(4):
-
-sage: F = J.base_ring()
-sage: a0 = (1/4)*X[4]**2*X[6]**2 - (1/2)*X[2]*X[5]*X[6]**2 - (1/2)*X[3]*X[4]*X[6]*X[7] + (F(2).sqrt()/2)*X[1]*X[5]*X[6]*X[7] + (1/4)*X[3]**2*X[7]**2 - (1/2)*X[0]*X[5]*X[7]**2 + (F(2).sqrt()/2)*X[2]*X[3]*X[6]*X[8] - (1/2)*X[1]*X[4]*X[6*X[8] - (1/2)*X[1]*X[3]*X[7]*X[8] + (F(2).sqrt()/2)*X[0]*X[4]*X[7]*X[8] + (1/4)*X[1]**2*X[8]**2 - (1/2)*X[0]*X[2]*X[8]**2 - (1/2)*X[2]*X[3]**2*X[9] + (F(2).sqrt()/2)*X[1]*X[3]*X[4]*X[9] - (1/2)*X[0]*X[4]**2*X[9] - (1/2)*X[1]**2*X[5]*X[9] + X[0]*X[2]*X[5]*X[9]
-
-5. Profile the construction of "large" matrix algebras (like the
-   15-dimensional QuaternionHermitianAlgebra(3)) to find out why
-   they're so slow.
+5. In CartesianProductEJA we already know the multiplication table and
+   inner product matrix. Refactor things until it's no longer
+   necessary to duplicate that work.