X-Git-Url: http://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=mjo%2Feja%2FTODO;h=f0901ca91b793debc4877a8ee5a670d240fa51fc;hb=f1ddf1e9eee634161aad87b9c2de0194efb17879;hp=7285d4aae1c90713348bfbc7126e78d67958944c;hpb=8b74269d8c59aa31306f1de713d6ce3fab9cb5de;p=sage.d.git diff --git a/mjo/eja/TODO b/mjo/eja/TODO index 7285d4a..f0901ca 100644 --- a/mjo/eja/TODO +++ b/mjo/eja/TODO @@ -1,3 +1,42 @@ 1. Add CartesianProductEJA. -2. Check the axioms in the constructor when check != False? +2. Add references and start citing them. + +3. Implement the octonion simple EJA. + +4. Override random_instance(), one(), et cetera in DirectSumEJA. + +5. Switch to QQ in *all* algebras for _charpoly_coefficients(). + This only works when we know that the basis can be rationalized... + which is the case at least for the concrete EJAs we provide, + but not in general. + +6. Pass already_echelonized (default: False) and echelon_basis + (default: None) into the subalgebra constructor. The value of + already_echelonized can be passed to V.span_of_basis() to save + some time, and using e.g. FreeModule_submodule_with_basis_field + we may somehow be able to pass the echelon basis straight in to + save time. + + This may require supporting "basis" as a list of basis vectors + (as opposed to superalgebra elements) in the subalgebra constructor. + +7. The inner product should be an *argument* to the main EJA + constructor. Afterwards, the basis normalization step should be + optional (and enabled by default) for ALL algebras, since any + algebra can have a nonstandard inner-product and its basis can be + normalized with respect to that inner- product. For example, the + HadamardEJA could be equipped with an inner- product that is twice + the usual one. Then for the basis to be orthonormal, we would need + to divide e.g. (1,0,0) by <(1,0,0),(1,0,0)> = 2 to normalize it. + +8. Pre-cache charpoly for some small algebras? + +9. Compute the scalar in the general natural_inner_product() for + matrices, so no overrides are necessary. + +10. The main EJA element constructor is happy to convert between + e.g. HadamardEJA(3) and JordanSpinEJA(3). + +11. Figure out if CombinatorialFreeModule's use of IndexedGenerators + can be used to replace the matrix_basis().