Re: [Maxima-discuss] Stop simplifying a subexpression

[Oleg N. <ol...@re...>]

On 08/07, Robert Dodier wrote:
>
> On Thu, Aug 7, 2025 at 1:09 PM Michael Gough
> <inn...@gm...> wrote:
> >
> > I need to prevent maxima from maxima from simplifying a subexpression. Let’s say I have x+x.
> >
> > Try as I might, I can not keep it from becoming 2x.
>
> Mike, take a look at a little package I wrote called superq (for
> superquote). You can find it in the folder robert-dodier/superq at:
> https://github.com/maxima-project-on-github/maxima-packages

Thanks, I will probably use it ;)

On a related note... From time to time I do something like

	(%i1) '"+"(2,2) = 4;
	(%o1)                              2 + 2 = 4

without "simp: false" and then I can copy the unsimplified expression somewhere.
This mostly works, but

	(%i2) '"."(matrix([1, 2], [3, 4]),  matrix([1], [2])) = matrix([5],[11]);
				  ┌      ┐     ┌   ┐    ┌    ┐
				  │ 1  2 │     │ 1 │    │ 5  │
	(%o2)                    (│      │) . (│   │) = │    │
				  │ 3  4 │     │ 2 │    │ 11 │
				  └      ┘     └   ┘    └    ┘
looks a bit worse.

If I do

	(%i3) :lisp (def-lbp $matrix 201)
	(%i3) :lisp (def-rbp $matrix 201)

then

	(%i3) '"."(matrix([1, 2], [3, 4]),  matrix([1], [2])) = matrix([5],[11]);
				   ┌      ┐   ┌   ┐   ┌    ┐
				   │ 1  2 │   │ 1 │   │ 5  │
	(%o3)                      │      │ . │   │ = │    │
				   │ 3  4 │   │ 2 │   │ 11 │
				   └      ┘   └   ┘   └    ┘

and this matches "matrix([1, 2], [3, 4]) . matrix([1], [2]) = matrix([5],[11])"
with "simp: false".

	:lisp (defprop %mnctimes 130. lbp)
	:lisp (defprop %mnctimes 129. rbp)

works too and probably makes more sense, this matches "(defprop mnctimes ...)"
in src/grind.lisp.

Another simple example:

	(%i4) a = b . c;
	(%o4)                              a = b . c
	(%i5) '"="(a, b.c);
	(%o5)                             a = (b . c)
	(%i6) :lisp (defprop %mequal 80. lbp)
	(%i6) :lisp (defprop %mequal 80. rbp)
	(%i6) '"="(a, b.c);
	(%o6)                              a = b . c

so perhaps it makes sense to update src/grind.lisp even if this all is
purely cosmetic?

Oleg.