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[Axiom-mail] Re: [fricas-devel] Re: InputForm
From: |
Bill Page |
Subject: |
[Axiom-mail] Re: [fricas-devel] Re: InputForm |
Date: |
Wed, 3 Jun 2009 10:35:09 -0400 |
On Wed, Jun 3, 2009 at 10:20 AM, Martin Rubey wrote:
>
> Bill Page writes:
>> Note also that
>>
>> y^2+x
>>
>> is not syntactically identical to the input
>>
>> x+y^2
>>
>> I wonder why FriCAS changes the order?
>
> Because the semantics is the same.
Yes, thanks. Now I understand. In the expression:
(x+y^2 )::INFORM
'(x+y^2 )' is first fully interpreted by Fricas as a polynomial and
only then does it coerce (convert?) the result back to InputForm. To
do what I expected I guess one could write:
(1) -> unparse(parse("x+y^2")$InputForm)
(1) "x+y^2"
Type: String
Then no semantics are involved but if invoke the interpreter explicitly
(2) -> unparse(interpret(parse("x+y^2")$InputForm)::INFORM)
(2) "y^2+x"
Type: String
then of course I get the result you showed.
> Currently, + is always commutative I think, but compare:
>
> (18) -> a:XPOLY INT := y*x
>
> (18) y x 1
> Type: XPolynomial(Integer)
> (19) -> b:POLY INT := x*y
>
> (19) x y
> Type: Polynomial(Integer)
>
> well, embarassingly enough, there is no INFORM for XPOLY :-(
>
Of course there should be such a coercion.
You are right that the result depends on the domain chosen by the interpreter.
Regards,
Bill Page.
- [Axiom-mail] InputForm, Ralf Hemmecke, 2009/06/03
- Re: [Axiom-mail] InputForm, Martin Rubey, 2009/06/03
- Re: [fricas-devel] Re: [Axiom-mail] InputForm, Bill Page, 2009/06/03
- Re: [fricas-devel] Re: [Axiom-mail] InputForm, Ralf Hemmecke, 2009/06/03
- Re: [fricas-devel] Re: [Axiom-mail] InputForm, Gabriel Dos Reis, 2009/06/03
- Re: [fricas-devel] Re: [Axiom-mail] InputForm, Ralf Hemmecke, 2009/06/03
- Re: [fricas-devel] Re: [Axiom-mail] InputForm, Bill Page, 2009/06/03
- Re: [fricas-devel] Re: [Axiom-mail] InputForm, Gabriel Dos Reis, 2009/06/03
- Re: [fricas-devel] Re: [Axiom-mail] InputForm, Ralf Hemmecke, 2009/06/03
- Re: [fricas-devel] Re: [Axiom-mail] InputForm, Gabriel Dos Reis, 2009/06/03
- Re: [fricas-devel] Re: [Axiom-mail] InputForm, Tim Daly, 2009/06/04
- Re: [fricas-devel] Re: [Axiom-mail] InputForm, Gabriel Dos Reis, 2009/06/04