[Maxima] single quote

Stavros Macrakis macrakis at alum.mit.edu
Mon Oct 5 14:02:09 CDT 2009

```On Mon, Oct 5, 2009 at 1:38 PM, Leo Butler <l.butler at ed.ac.uk> wrote:

> On Mon, 5 Oct 2009, Stavros Macrakis wrote:
>
> < Yes, it is accurate.  You could also show the same thing with '+', which
> < might motivate the behavior better:
> <
> < 1+2.0 => 3.0
> < '(1+2.0) => 3.0
> < '(x+1+2.0) => x+3.0
>
> These examples muddy the water,

The intent was to *clarify* the water by showing the parallel between the
operation of adding 1 (or x+1) to 2.0 to the operation of taking the sin of
2.0.

> because they clearly are
> 'simplifications'. There is some arbitrary line that separates a
> 'simplification' from an 'evaluation' (e.g. in your examples above, one
> can say that the '+' function is being evaluated.).

Why would you say that 1+2=>3 is an "evaluation" (though not in Maxima
terms), but x+2*x => 3*x is an "evaluation"?  What about %i+2*%i?

The line is not arbitrary at all for mathematical functions.  As I mentioned
in my last mail, where it gets somewhat more arbitrary is with operators
like "integrate".

> I was trying to find the line, because it is not where I would naively put
> it.
>

The line is very simple (except as I say for cases like 'integrate').  ALL
automatic transformations of expressions involving Maxima functions are
simplifications.

Things also get muddy for user-defined routines (better not to call them
functions...) -- users can define mathematical functions but only through
the pattern-matching mechanism.

-s
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