Re: [Maxima-discuss] Programatically extract the summand of the innermost sum

[Robert D. <rob...@gm...>]

On 2015-06-05, Marduk Bolaños <mar...@ma...> wrote:

> The goal is to use one of the answers I got to my previous question on
> applying a function under the summation sign, but now it is not only one
> summation sign but several.

How about:

  matchdeclare (ss, lambda ([e], not mapatom(e) and (op(e) = 'sum or
    op(e) = nounify('sum))));
  tellsimp (f(ss), apply (op(ss), cons (f(first(ss)), rest(args(ss)))));

and then for example:

  f('sum('sum('sum(a[i,j,k],i,1,m),j,1,n),k,1,o));
   => 'sum('sum('sum(f(a[i,j,k]),i,1,m),j,1,n),k,1,o)
  subst (f=lambda([x], x^2), %);
   => 'sum('sum('sum(a[i,j,k]^2,i,1,m),j,1,n),k,1,o)

??

best

Robert Dodier