From: Michael Orlitzky Date: Wed, 3 Mar 2021 04:45:48 +0000 (-0500) Subject: eja: refactor _all2list to support forthcoming matrix algebras. X-Git-Url: https://gitweb.michael.orlitzky.com/?a=commitdiff_plain;h=b0044b0f4a417ecbdf72a9d13b268fd7f94694de;p=sage.d.git eja: refactor _all2list to support forthcoming matrix algebras. --- diff --git a/mjo/eja/eja_utils.py b/mjo/eja/eja_utils.py index 832dcef..430113d 100644 --- a/mjo/eja/eja_utils.py +++ b/mjo/eja/eja_utils.py @@ -46,9 +46,18 @@ def _all2list(x): Flatten a vector, matrix, or cartesian product of those things into a long list. - EXAMPLES:: + If the entries of the matrix themselves belong to a real vector + space (such as the complex numbers which can be thought of as + pairs of real numbers), they will also be expanded in vector form + and flattened into the list. + + SETUP:: sage: from mjo.eja.eja_utils import _all2list + sage: from mjo.octonions import Octonions, OctonionMatrixAlgebra + + EXAMPLES:: + sage: V1 = VectorSpace(QQ,2) sage: V2 = MatrixSpace(QQ,2) sage: x1 = V1([1,1]) @@ -65,15 +74,35 @@ def _all2list(x): sage: _all2list(M((x2,y2))) [1, -1, 0, 1, 1, 0] + :: + + sage: _all2list(Octonions().one()) + [1, 0, 0, 0, 0, 0, 0, 0] + sage: _all2list(OctonionMatrixAlgebra(1).one()) + [1, 0, 0, 0, 0, 0, 0, 0] + """ - if hasattr(x, 'list'): - # Easy case... - return x.list() - else: - # But what if it's a tuple or something else? This has to - # handle cartesian products of cartesian products, too; that's - # why it's recursive. - return sum( map(_all2list,x), [] ) + if hasattr(x, 'to_vector'): + # This works on matrices of e.g. octonions directly, without + # first needing to convert them to a list of octonions and + # then recursing down into the list. It also avoids the wonky + # list(x) when x is an element of a CFM. I don't know what it + # returns but it aint the coordinates. This will fall through + # to the iterable case the next time around. + return _all2list(x.to_vector()) + + try: + xl = list(x) + except TypeError: # x is not iterable + return [x] + + if len(xl) == 1: + # Avoid the retardation of list(QQ(1)) == [1]. + return xl + + return sum(list( map(_all2list, xl) ), []) + + def _mat2vec(m): return vector(m.base_ring(), m.list())