Parallel programming and parfor

I have a couple of questions. what is sliced variable? please bring a clear example. How should use parfor when you have a for inside another for loop?

Thanks

Answer 1

[Walter Roberson]

http://www.mathworks.com/help/distcomp/sliced-variables.html

[Mohammad]

Example - How do use sliced variable in

CE=c./(absXini);
for i=1:m1
    CE(i,i)=0; 
end

if you want to see errors, simply add 'par' before for and read errors in details.

[Walter Roberson]

The documentation there makes clear that the loop index may only appear once in the indexing expression; your code tries to use it twice.

Equivalent code that can be run with parfor, presuming a square 2D array

for i = 1 : size(CE,1)+1 : (m1-1)*size(CE,1)+m1
   CE(i) = 0;
end

Other equivalent:

t = zeros(m1,1);
for i = 1 : m1
  t(i) = 0;  %redundant in the case of 0
end
CE(1:size(CE,1)+1:(m1-1)*size(CE,1)+m1) = t; %must be outside

And there is the vector version (not usable inside parfor)

CE(sub2ind(size(CE),1:m1,1:m1)) = 0;

Some of these can be simplified for the case where m1 is the same as size(CE,1) and the matrix is square, including

CE = CE - diag(diag(CE));