JuMP variable definition

[ar.sh...@gmail.com]

hello, I decided to implement Power Flow problem in julia, but while i cannot been determined the variable because when i defined, a set of special type of busess active powers(or other variables), the previously defined active powers are eliminated.
@variable(PF, P[i=1:nGen; bus[:,2][i] == 2] == gen[:,2][i]/baseMVA)
@variable(PF, P[i=1:nBus; bus[:,2][i] == 1] == -bus[:,3][i]/baseMVA)
can you help me?

_

[Carleton Coffrin]

Hi,

I can see two options,

1) Precompute a p_delta for each bus, which is the sum of generator output and bus load.  Then post KCL for each bus of the form,

for i in buses

  @constraint(p_delta[i] == sum{ p[(i,j)] for (i,j) in  bus_edges[i] })

end

2) Break up your p values into demands and generation, then you can post,

for i in buses

  @constraint(p_gen[i] - p_load[i] == sum{ p[(i,j)] for (i,j) in  bus_edges[i] })

end

Depending on your use case, you might also consider using PowerModels.jl 

It supports both AC and DC power flow computations.

Cheers,

-Carleton

[ar.sh...@gmail.com]

thanks for your help

[Miles Lubin]

Repeated definition of a variable with the same name will generate a warning in the next release of JuMP.

[ar.sh...@gmail.com]

how i can defined different bounds or fixed values to elements of a vector variable?