CODEWITHSUNDEEP
maxima
Joe Ali
Joe Ali

Reputation: 33

How to Subst symbolic variables in Maxima

I have a long list containing something like

a:[1, a, -b, -a*b, j, -j, j^2, -j^3, a*j, a*j^2, -a*j,- a*j^2, a*b*j, a*j^4, -a*b*j^7];

I would like to perform substitution like j^x -> j^(3 mod x)

Basically replace every occurrence in the list of the pattern j^x (where x = 0 to 100) with j^(3 mod x).

subst and ratsubst etc seem to look for a pattern literally not symbolically.

Is there a way to do this in Maxima?

Thanks

Upvotes: 1

Views: 585

Answers (1)

Robert Dodier
Robert Dodier

Reputation: 17577

I think you can use pattern matching for this. (Pattern matching in the sense of matching expressions, not strings.) tellsimp and tellsimpafter define rules that are applied automatically; defrule and defmatch define rules that are applied explicitly. See also matchdeclare.

A solution via defrule might look like this; I haven't tried it.

matchdeclare (nn, lambda ([e], integerp(e) and e >= 3));
defrule (r1, j^nn, j^(mod(3, nn)));
apply1 (mylist, r1);

where mylist is the list above. (I think assigning the list to a is problematic, since a appears as a term in the products ....)

Upvotes: 2

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