Transparency is violated by the save command because in general MATLAB cannot determine which variables from the workspace will be saved to a file.
Pre-R2024a
The solution is to move the call to save to a separate function and to call that function from inside the parfor loop. Pass any variables that are to be saved as arguments to the function. That way MATLAB can determine which ones will be saved and transparency is not violated.
For example:
Save the following as "parsave.m":
function parsave(fname, x,y)
save(fname, 'x', 'y')
end
Then run it with:
parfor ii = 1:4
x = rand(10,10);
y = ones(1,3);
parsave(sprintf('output%d.mat', ii), x, y);
end
R2024a Onwards
MATLAB now supports calling save within a parfor loop when the -fromstruct option is used.
The following documentation example demonstrates how to collect your variables into a struct and then save inside the parfor loop.
