MATLAB Answers

How to resolve indexing the sliced variable error in the case of for nested with parfor?

39 views (last 30 days)
Rahul Bhadani
Rahul Bhadani on 29 Apr 2021
Answered: Edric Ellis on 30 Apr 2021
I have following use case:
Nth = 102;
p = 0.0000001:0.1:0.99999;
NthArray = (Nth - 100 > 0)*Nth + (Nth - 100 <=0)*1:1:Nth+100;
III = zeros( length(p), length(NthArray));
parfor ip = 1:numel(p)
for inth = 1:numel(NthArray)
III(ip, inth) = g( p(ip), ntharray(inth));
end
end
However, upon running it I get following error:
Error: When indexing the sliced variable 'III', the range of the for-loop variable 'inth' must be a row vector of positive constant numbers or variables. For more information, see Parallel
for Loops in MATLAB, "Nested for-Loops with Sliced Variables".
How should I resolve this error?
Thanks.

Answers (1)

Edric Ellis
Edric Ellis on 30 Apr 2021
The problem here is that the inner loop bounds must be a constant - basically this means that you must compute it outside the parfor loop, like so:
Nth = 102;
p = 0.0000001:0.1:0.99999;
NthArray = (Nth - 100 > 0)*Nth + (Nth - 100 <=0)*1:1:Nth+100;
III = zeros( length(p), length(NthArray));
% Must calculate inner loop bounds outside the PARFOR loop:
n_Nth = numel(NthArray);
g = @plus; % Dummy definition of "g"
parfor ip = 1:numel(p)
for inth = 1:n_Nth
III(ip, inth) = g( p(ip), NthArray(inth));
end
end
disp('Success!')
Success!

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!