If then else function

[reza1999]

Hi,
How to write this function in vensim?
Thanks in advance.

[tomfid]

Ugh.

The general framework will be something like:

QFP1 = IF THEN ELSE( tfp>0
, IF THEN ELSE( expression beginning with pp>0
,expression beginning with sum over QH
,expression beginning with sum over QH*fraction with pp in numerator )
, 0 )

It's pretty confusing subscripting though - I would strongly encourage making each summation a separate variable.