GAMS sum and prod syntax_ what different?

GAMS
1

Hi all,

I read GAMS manual and find some unclear points.
I want to know what is the prod meaning in GAMS?
I know that it uses same sysntax as sum. But I am not sure what is it implying in economics.

Sum(j, x(j)) = x1+x2+x3+…xn
What prod(j, x(i, j)) is equivalent to?

Note that I see it uses with objective function.

obj… UU =e= prod(i,x(i)**alpha(i));

Anyone, please help clarify me.
Thank you,

2

Hi,

The product operation prod() represents the capital pi notation (see https://en.wikipedia.org/wiki/Multiplication#Capital_Pi_notation).
This is similar to the sum operation sum() representing the captal sigma notation (https://en.wikipedia.org/wiki/Summation#Capital-sigma_notation)

I hope this helps!

Fred

3

Hi Fred,

Many thanks for your reply.
I totally understand it now.

Best regards,

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