Proper classification of variables in parfor loop

Hi there I have a loop that I would like to run with parfor. A simplified version of the code is

parfor qx_index=1:Nsx*Nx
    for qy_index=1:Nsx*Nx        
        chi(qx_index,qy_index,:)=function(other_variables,qx_index,qy_index) 
    end
end

When I run the code I get the following error:

Error: The variable chi in a parfor cannot be classified.

I cannot figure out why this doesn't work - help?

Answer 1

[Sean de Wolski]

What you have above works fine for me (filling in a few of the blanks)...

chi = zeros(2,3);
parfor qx_index=1:2
  for qy_index=1:3
      chi(qx_index,qy_index,:)=afunction(qx_index,qy_index) 
  end
end

And

function z  = afunction(y,x)
z = y*x;

[Henrik]

Hmm, that is really weird! Your example also works for me. Could it be something specific in the function that I am using? I could upload everything, but it's a rather large project with several files...

[Adam]

There are a number of rules surrounding the functions you can use in a parfor loop. For example you cannot use nested functions or non-transparent functions like eval. Maybe your function does not meet these criteria?

[Henrik]

Uhuh, it is a rather complicated function, so that might be the issue. On the other hand, it works if I do

for qx_index=1:Nsx*Nx
  parfor qy_index=1:Nsx*Nx        
    chi(qx_index,qy_index,:)=function(other_variables,qx_index,qy_index) 
  end
end