VsCode julia execute file and while loop

Hi,

I have a script with a while loop. When I run the code using “Shift+Enter”, “Alt+Enter” or even “Execute Code” everything is fine. But when I use “Execute file”, two errors I get (1) the global variables are not recognised inside the while loop, (2) it cannot exit the while loop.

I appreciate any advice.

Hi, could you provide an example of your code?

My guess is that you mean what’s discussed here (minute 20:30). Hope it helps.

https://youtu.be/xKrIp4ZVOrg

Thanks for the rely. Below is the code, either loop can be safely commented out. In the first loop it does not recognise kWsum, and in the second loop, it just gets stuck.

using Pkg
Pkg.activate(pwd())
Pkg.add("OpenDSSDirect")
using OpenDSSDirect

dss("""
    Clear
    New Circuit.Kersting_nr_LineGeometry_Balanced phases=3 basekv=12.47 bus1=B1 MVASC1=1e8 MVASC3=1e8
    New Wiredata.Hawk DIAM=0.858 GMR=0.029 RAC=0.216
    ~ NormAmps=530                                  // this param is not defined
    ~ Runits=mi radunits=in gmrunits=ft
    New Linegeometry.OverHead1 nconds=4 nphases=3
    ~ cond=1 Wire=Hawk   x=-48   h=348  units=in
    ~ cond=2 Wire=Hawk   x=-21   h=348  units=in
    ~ cond=3 Wire=Hawk   x=40    h=348  units=in
    ~ cond=4 Wire=Hawk   x=0     h=286  units=in   // h is not defined
    New Line.Line1 bus1=B1.1.2.3.0 bus2=B2.1.2.3.4
    ~ Geometry=OverHead1
    ~ Length=1.893939 units=mi
    ~ EarthModel=Carson
    New Reactor.grounding phases=1 bus1=B1.4 bus2=B1.0 R=100 X=0.01
    New Load.LoadP1  phases=1 bus1=B2.1.4  kv=12.47  model=1 conn=wye kVA=3000  pf=0.9 vminpu=0.1 vmaxpu=2
    New Load.LoadP2  phases=1 bus1=B2.2.4  kv=12.47  model=1 conn=wye kVA=3000  pf=0.9 vminpu=0.1 vmaxpu=2
    New Load.LoadP3  phases=1 bus1=B2.3.4  kv=12.47  model=1 conn=wye kVA=3000  pf=0.9 vminpu=0.1 vmaxpu=2
    Set Toler=0.00000001
    Solve
""")

solution = Dict{String,Any}()

# load power
solution["load"] = Dict{String,Any}()
loadnumber = Loads.First()
kWsum = 0.0
kvarsum = 0.0
while loadnumber > 0
    load_name = Loads.Name()
    solution["load"][load_name] = Dict{String,Any}()
    solution["load"][load_name]["pd"] = Loads.kW()
    solution["load"][load_name]["qd"] = Loads.kvar()
    kWsum += Loads.kW()
    kvarsum += Loads.kvar()
    loadnumber = Loads.Next()
end

# line currents
solution["line"] = Dict{String,Any}()
linenumber = PDElements.First()
while linenumber > 0
    name = PDElements.Name()
    Circuit.SetActiveElement(name)
    if split(name,".")[1] == "Line"
        line_name = split(name,".")[2]
        @show line_name
        solution["line"][line_name] = Dict{String,Any}()
        solution["line"][line_name]["bus_fr"] = Lines.Bus1()
        solution["line"][line_name]["bus_to"] = Lines.Bus2()
        solution["line"][line_name]["nphases"] = Lines.Phases()
        solution["line"][line_name]["linecode"] = Lines.LineCode()
        solution["line"][line_name]["zmatrix"] = Lines.ZMatrix()
        solution["line"][line_name]["length"] = Lines.Length()
        solution["line"][line_name]["unit"] = Lines.Units()
        solution["line"][line_name]["c"] = PDElements.AllCurrentsAllCurrents()[1:Lines.Phases()]
    end
   linenumber = PDElements.Next()
end

This is expected, you defined kWsum in a global scope, but the for loop will create its own local variable kWsum by default unless you make it explicitly global. This may look like a weird design decision, but it’s intended to reduce the risk of affecting unintentionally a distant global variable.

You are doing this.

var = 1.0 # global
for i in 1:10
    var += 1 # uninitialized new local
end 
println(var)
# ERROR: LoadError: UndefVarError: var not defined
# Stacktrace:
# [...]

To solve this the general advice, I think, is to grab all your code in a function (which introduce a local scope). This also have many other advantages (performance included). But if you wanna work in the global scope anyway you can do

var = 1.0 # global
for i in 1:10
    global var += 1 # reusing global
end 
println(var)
# 11.0

But to understand better I recommend you to read the manual and do a couple of examples.