Dear John,
On 8 Feb., 10:40, "John Cremona" <[EMAIL PROTECTED]> wrote:
> In your first example, where you have not defined x, ...
... but it is pre-defined, and explicitly saying "var('x')" has the
same effect.
> In this
> system, "==" is used to create equations, not to test equality.
That's nasty!
My personal opinion is: When i say "==" in Sage then i expect a
consistent behaviour, hence, a test for equality. Certainly the __eq__
method can do whatever the programmer wants, but it would be good
style to make it consistent with the rest of Sage.
Working in Sage, i do believe that Sage's conventions should overrule
the conventions of any sub-system. Hence, if i want "==" to be
interpreted in the Maxima-way, i would express that wish explicitly,
say, by
maxima('x==x')
However, i do understand that this would hardly be possible to change
now.
By the way, i just tested "maxima('x==x')", and Sage *freezes*!
Why?
> In your second example, you are creating a specific ring containing an
> element x, namely the ring of polynomials on one variable x over QQ.
Maxima does some simplifications automatically. How can i do the same
for polynomials over QQ? Note that simplify(((x^4+1)/((-1)*x^2)))
again returns (x^4 + 1)/-x^2.
Thank you for your answer, that made me understand the reason for the
different behaviour of "==" (although i don't like it).
Now i would like to understand why "maxima('x==x')" is so difficult
for Sage. It doesn't give an error, it simply hangs.
Yours sincerely
Simon
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