First of all thanks a lot for noticing my question

I’m new to julia and JuMP and all my experience using them has been just a couple of days

Here are my answers to your questions:

1.This matrix was a csv file which I read using `CSV`

and converted it to a `DataFrame`

because in other constraints I need to select some special columns (based on column name).Having worked with pandas in python , I did so. If there is a better way of doing this please inform me.

2.The error I’ve mentioned is not related to the `.`

as I played with the code and deleted and wrote the dot ,but I got same error!(I’ve just accidentally copied the “without dot” version here)

3.Thank you so much ,`dot`

worked for me!!

there’s a problem with another constraint which is nonlinear:

“Unexpected array VariableRef in nonlinear expression. nonlinear expressions may contain only scalar expressions”

here is the constraint:

`@NLconstraint(model,[sum(c[j]*v[indx_of_P[j]]) for j in 1:length(c)] ==uptake*g )`

I tried to define a function, but it didn’t work

`f(x,y)=sum(x[j]*y[indx_of_P[j]] for j in 1:length(x))`

` @NLconstraint(model,f(c,v)==uptake*g )`