Re: [Maxima-discuss] makelist, map (and probably others) returning unsimplified lists -> extra simplifier calls

[Barton W. <wi...@un...>]

FYI: In case somebody doesn't know, the functions cons and friends are more general than are push and pop; for example:

(%i1) cons(3,a*b);
(%o1)  3 a b


(%i2) cons(p+q, a*b);
(%o2)   a b (q + p)


--Barton

________________________________
From: David Scherfgen via Maxima-discuss <max...@li...>
Sent: Thursday, March 6, 2025 00:14
To: Richard Fateman <fa...@gm...>
Cc: <max...@li...> <max...@li...>
Subject: Re: [Maxima-discuss] makelist, map (and probably others) returning unsimplified lists -> extra simplifier calls

Caution: Non-NU Email

I gave a wrong number previously.
The actual number of simplifier calls in the code that creates 100,000 list elements is 5 billion.

$push doesn't cause resimplification of the entire list because it calls the simplifier with the second argument T. There's a comment in there by Barton:

;; We assume that if each member of a list is simplified, the list members are still simplified
;; after pushing onto (or popping) the list. Just before returning, the code calls simplifya
;; with second argument true. Without this call to simplifya, the general simplifier would simplify
;; every list member after returning. (Barton Willis, author of $push and $pop)

$cons, $endcons and other functions should operate on the same assumption. I'm collecting all the affected functions to fix them.