X-Git-Url: http://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=mjo%2Feja%2FTODO;h=1def3d2e9fd8cf381ae743344ce670a13f226438;hb=cc172fbdcd369542f90cf64e31611cf8698bc05a;hp=310e3073c667fb42b7591c0b8a989f590455e4fa;hpb=197e8fdf8737fabde9003bd093cf45527afd4568;p=sage.d.git

diff --git a/mjo/eja/TODO b/mjo/eja/TODO
index 310e307..1def3d2 100644
--- a/mjo/eja/TODO
+++ b/mjo/eja/TODO
@@ -1,38 +1,20 @@
 1. Add references and start citing them.
 
-2. Pre-cache charpoly for some small algebras?
+2. Profile (and fix?) any remaining slow operations.
 
-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]
-
-3. Profile the construction of "large" matrix algebras (like the
-   15-dimensional QuaternionHermitianAlgebra(3)) to find out why
-   they're so slow.
-
-4. Instead of storing a basis multiplication matrix, just make
-   product_on_basis() a cached method and manually cache its
-   entries. The cython cached method lookup should be faster than a
-   python-based matrix lookup anyway. NOTE: we should still be able
-   to recompute the table somehow. Is this worth it?
-
-5. What the ever-loving fuck is this shit?
-
-       sage: O = Octonions(QQ)
-       sage: e0 = O.monomial(0)
-       sage: e0*[[[[]]]]
-       [[[[]]]]*e0
-
-6. Can we convert the complex/quaternion algebras to avoid real-
-   (un)embeddings? Quaternions would need their own
-   QuaternionMatrixAlgebra, since Sage matrices have to have entries
-   in a commutative ring.
-
-7. Every once in a long while, the test
+3. Every once in a long while, the test
 
        sage: set_random_seed()
        sage: x = random_eja().random_element()
        sage: x.is_invertible() == (x.det() != 0)
 
-   in eja_element.py returns False.
+   in eja_element.py returns False. Example:
+
+       sage: J1 = ComplexHermitianEJA(2)
+       sage: J2 = TrivialEJA()
+       sage: J = cartesian_product([J1,J2])
+       sage: x = J.from_vector(vector(QQ, [-1, -1/2, -1/2, -1/2]))
+       sage: x.is_invertible()
+       True
+       sage: x.det()
+       0