How to minimize Sum in Maple

Question

I have the following problem - I need to minimize the sum in the maple. For example, suppose I have this:

EXPESSION:=A[0]+A[1]+A[2]+A[3]+A[4]+A[5];

And I want to use some function

someFunction(EXPRESSION);

which will return a symbol of the Sum (like sum(A[i], i = 0 .. 5));

Is some function like that exists?

Answer 1

Okay, I guess that you need something to compress an existing expession. If you're willing to specify the summand, index, and index range, then someFunction could subtract the terms and add the (unevaluated) Sum of those terms.

convert_to_Sum:= (ex, summand, index)->
    simplify(ex - sum(summand, index) + Sum(summand, index))
;

Example:

ex:= A[0]+A[1]+A[2]+A[3]+A[4]+A[5];
convert_to_Sum(ex, A[i], i= 0..5);

Answer 2

Use Sum(A[i], i= 0..5) Note that Sum is uppercase. I realize that this does not handle the case where the expression already exists, which may be what you are primarily interested in.