Scoping Experiment

This experiment is designed to show a pecularity in Julia'd scoping. Julia uses a layered scoping where the scope of the inner function has access to the values of the outer function. For example:



In [1]:

    
x=5; y=7; #Defined globally
function scopeTest(z)
  x += z #Changes global value
  y = Vector{Float64}(1) #Declares a variable, local scope
  y[1] = 2
  return x + y + z
end









    Out[1]:





scopeTest (generic function with 1 method)

However, what is happening here, and why?



In [6]:

    
using Distributed
addprocs(1)
function f1()
  @distributed for i = 1:100
    x = 10
    if x < 100
      x = x + 1
    end
  end
  x = x + 100 + 10
  return x
end
f1()









    



UndefVarError: x not defined

Stacktrace:
 [1] macro expansion at /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.0/Distributed/src/macros.jl:337 [inlined]
 [2] f1() at ./In[6]:4
 [3] top-level scope at In[6]:13



In [7]:

    
function f2()
  @distributed for i = 1:100
    x = 10
    if x < 100
      x = x + 1
    end
  end
  return x
end
f2()









    Out[7]:





5