[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Axiom-developer] Question concerning types...
From: |
Martin Rubey |
Subject: |
Re: [Axiom-developer] Question concerning types... |
Date: |
16 Sep 2006 18:51:09 +0200 |
User-agent: |
Gnus/5.09 (Gnus v5.9.0) Emacs/21.3 |
C Y <address@hidden> writes:
> Question came up on IRC, and I'm curious. Given the following:
>
> AXIOM Computer Algebra System
> Version: Axiom (September 2006)
> Timestamp: Saturday September 9, 2006 at 11:29:25
> -----------------------------------------------------------------------------
> Issue )copyright to view copyright notices.
> Issue )summary for a summary of useful system commands.
> Issue )quit to leave AXIOM and return to shell.
> -----------------------------------------------------------------------------
>
> Re-reading compress.daase Re-reading interp.daase
> Re-reading operation.daase
> Re-reading category.daase
> Re-reading browse.daase
> (1) ->
> (1) -> a1 : Quaternion Fraction Integer
>
> Type: Void
> (2) -> a2 : Quaternion Fraction Integer
>
> Type: Void
> (3) -> a3 : Quaternion Fraction Integer
>
> Type: Void
> (4) -> a4 : Quaternion Fraction Integer
>
> Type: Void
> (5) -> a1
> 5) ->
> a1 is declared as being in Quaternion Fraction Integer but has not
> been given a value.
> (5) -> m := matrix[[a1,a2],[a3,a4]]
> 5) ->
> a1 is declared as being in Quaternion Fraction Integer but has not
> been given a value.
> (5) ->
>
> Why isn't this allowed? I want a1->a4 to be variables without assigned
> value, and I want to create a symbolic matric where all I know about
> the entries is their type, in order to do general solving operations.
> How would I set this up correctly in Axiom?
Currently, you can't. Note that you promise axiom that a1 is a Quaternion
Fraction Integer. However, you don't hold your promise...
What you want is to make a1 a variable. Currently, there is no domain of
"Variables, which can take values only in Quaternion Fraction Integer".
In fact, it is (or should be) a FAQ. See MathAction.
The point of Axioms type system is that any identifier has a typed value. There
is no such thing as a identifier that does not have a value.
If you type
5*a+a^2
into the interpreter, it responds with
Polynomial Integer.
When you say p:=5*a+3*a^2, the identifier p refers to this polynomial. The
internal representation is something like
[[5,a,1],[3,a,2]]
How would you represent a generic polynomial? You need a different domain for
that.
Martin
- [Axiom-developer] Question concerning types..., C Y, 2006/09/16
- Re: [Axiom-developer] Question concerning types...,
Martin Rubey <=
- Re: [Axiom-developer] Question concerning types..., C Y, 2006/09/16
- Re: [Axiom-developer] Question concerning types..., Ralf Hemmecke, 2006/09/16
- Re: [Axiom-developer] Question concerning types..., Gabriel Dos Reis, 2006/09/16
- Re: [Axiom-developer] Question concerning types..., C Y, 2006/09/16
- Re: [Axiom-developer] Question concerning types..., Martin Rubey, 2006/09/16
- Re: [Axiom-developer] Question concerning types..., Ralf Hemmecke, 2006/09/16
- Re: [Axiom-developer] Question concerning types..., Gabriel Dos Reis, 2006/09/16
- Re: [Axiom-developer] Question concerning types..., Gabriel Dos Reis, 2006/09/16
- Re: [Axiom-developer] Question concerning types..., C Y, 2006/09/16
- Re: [Axiom-developer] Question concerning types..., Gabriel Dos Reis, 2006/09/16