Actually, using Eq for tuples seems problematic as well. Maybe just something like ShapeEq((1, 1)), so the fact would be
Implies(ShapeEq((1, 1)) | ShapeEq((0, 0)), Q.diagonal) That's just one idea. There's lots of ways you can equivalently write the same thing. The goal is to make abstractions that make the facts as readable as possible. Aaron Meurer On Wed, Dec 14, 2016 at 4:42 PM, Aaron Meurer <[email protected]> wrote: > That looks good, although I might try to go for something more general. > Maybe we just need a Shape class that we can combine with Eq, like Eq(Shape, > (1, 1)) where Shape(A) evaluates as the shape of A. It wouldn't really be a > predicate, though, so maybe some more thought is needed here. > > Aaron Meurer > > On Wed, Dec 14, 2016 at 4:35 PM Andrey Torba <[email protected]> wrote: >> >> Aaron, what should be done in order to add new sat handlers? >> >> I'm thinking where to start from? sympy/assumptions/sathandlers.py: >> >> class IsEmptyOr1x1(UnevaluatedOnFree): >> >> def apply(self): >> return Equivalent(self.args[0], self.expr.shape == (0, 0) or >> self.expr.shape == (1, 1)) >> >> >> for klass, fact in [ >> ... >> (MatrixExpr, IsEmptyOr1x1(Q.diagonal)), >> (MatrixExpr, Implies(Q.diagonal, Q.symmetric)), >> ... >> ] >> >> >> On Monday, December 12, 2016 at 4:04:57 PM UTC-8, Aaron Meurer wrote: >>> >>> This is a downside of the handlers system. The deductions aren't made >>> >>> >>> based on facts that the handlers return. This is one of the main >>> >>> >>> deficiencies that the satask/sathandlers system tries to fix. I don't >>> >>> >>> know if there's an easy fix to make it work in the handlers system. >>> >>> >>> You could also manually modify the SymmetricHandler class to check for >>> >>> >>> diagonal (this is obviously annoying, because it blatantly duplicates >>> >>> >>> the general fact in get_known_facts >>> >>> >>> >>> https://github.com/sympy/sympy/blob/5827cafb1e1840915b3e7c9f62cd0d58fff9fc48/sympy/assumptions/ask.py#L1517). >>> >>> >>> >>> >>> >>> The better way to fix it is to implement it in the sathandlers system. >>> >>> >>> No matrix stuff is implemented there yet, so it may require some >>> >>> >>> ground work. >>> >>> >>> >>> >>> >>> Aaron Meurer >>> >>> >>> >>> >>> >>> On Mon, Dec 12, 2016 at 6:57 PM, Andrey Torba <[email protected]> wrote: >>> >>> >>> > Hi, >>> >>> >>> > >>> >>> >>> > I'm working on the pull request. >>> >>> >>> > >>> >>> >>> > A 1x1 matrix is always diagonal. Diagonal implies symmetric. I have >>> > fixed >>> >>> >>> > AskDiagonalHandler such that this assertion pass: >>> >>> >>> > >>> >>> >>> > V1 = MatrixSymbol('V1', 2, 1) >>> >>> >>> > V2 = MatrixSymbol('V2', 2, 1) >>> >>> >>> > expr = V1.T*(V1 + V2) >>> >>> >>> > assert ask(Q.diagonal(expr)) is True >>> >>> >>> > >>> >>> >>> > Now I assume that inference module will deduce that this expression is >>> > also >>> >>> >>> > symmetric (since the expression is diagonal): >>> >>> >>> > >>> >>> >>> > assert ask(Q.symmetric(expr)) is True # it is None! >>> >>> >>> > >>> >>> >>> > It returns None. Is anything missing? Can you show an example where >>> > this >>> >>> >>> > kind of inference works well? >>> >>> >>> > >>> >>> >>> > -Andrey >>> >>> >>> > >>> >>> >>> > -- >>> >>> >>> > You received this message because you are subscribed to the Google >>> > Groups >>> >>> >>> > "sympy" group. >>> >>> >>> > To unsubscribe from this group and stop receiving emails from it, send >>> > an >>> >>> >>> > email to [email protected]. >>> >>> >>> > To post to this group, send email to [email protected]. >>> >>> >>> > Visit this group at https://groups.google.com/group/sympy. >>> >>> >>> > To view this discussion on the web visit >>> >>> >>> > >>> > https://groups.google.com/d/msgid/sympy/d84286f8-9a6f-469b-ac95-4a3c8b21cda2%40googlegroups.com. >>> >>> >>> > For more options, visit https://groups.google.com/d/optout. >>> >>> >> >> >> >> >> >> >> >> >> -- >> >> >> You received this message because you are subscribed to the Google Groups >> "sympy" group. >> >> >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> >> >> To post to this group, send email to [email protected]. >> >> >> Visit this group at https://groups.google.com/group/sympy. >> >> >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/sympy/1e2b221a-2b4a-48f5-b1dc-44ff6ab0db28%40googlegroups.com. >> >> >> For more options, visit https://groups.google.com/d/optout. >> >> > -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAKgW%3D6JSOL64FDckwM2-swN61eHBUQgm31s1p0VYPYCEL-OsAw%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
