Object Indices in parfor loop

Hello,

I am trying to parallelize some code involving cellular signaling models. I am using an object called "ppiUpdater," which is defined by a class I've written. I am trying to call a function using that object inside a parfor loop and matlab tells me that the object ppiUpdater is not properly indexed.

Here is the code for the parfor loop:

newState=zeros(NCells, 1);

parfor iCell = 1:NCells

                  newState(iCell,1).ActiveReceptors = ...
                      ppiUpdater.evolveReceptors(arguments involving iCell);
end

Thanks in advance for any help!

[Satyajeet Sasmal]

Hi Ondrej,

Can you post your code and all relevant data that you use, here, so that I can reproduce the error?

Also, You might be incorrectly referencing your parfor loop. You can only reference the "i-th" element (not "(i+1)-th" or "(i-1)-th" elemnt) in "i-th" iteration of the loop. Please refer to the third paragraph of the link mentioned below for possible issue resolution.

http://www.mathworks.com/help/distcomp/introduction-to-parfor.html

[Walter Roberson]

(i+1) and (i-1) are valid for indexing for loop variable i, but it must be consistent -- you cannot reference both (i) and (i-1) . See http://www.mathworks.com/help/distcomp/sliced-variables.html

Answer 1

[Edric Ellis]

If ppiUpdater is an object instance that you're trying to call a method of, you might want to use the "functional" form of method invocation, like so:

evolveReceptors(ppiUpdater, arguments involving iCell);

This entirely equivalent to the dot-reference version, except that parfor will not interpret it as an indexing expression.

[Ondrej]

Thanks all. I found the error was in another part of the code involving an instance variable associated with the object not being indexed correctly. Not sure why matlab would show the error in the above function call, but I guess it did!