MATLAB Answers

Tmfu Vh
0

How to call protected functions in parfor?

Asked by Tmfu Vh
on 26 Jul 2019
Latest activity Commented on by Tmfu Vh
on 30 Jul 2019
This function is inside the common methods block of a class.
function GetWavelets(Me)
%Unrelated codes omitted…
parfor c=1:ttpc
%Me is the object itself, OnProgressReport is protectedly defined.
Me.OnProgressReport(c,ttpc);
%…
end
%…
end
The protected function OnProgressReport is unaccessible in the parfor loop. I found two workarounds:
  • Use for loop instead of parfor;
  • Set the Access attribute of OnProgressReport to public.
If I want to preserve the parfor loop for performance reasons, is it unavoidable to expose the OnProgressReport to public? Any other solutions?
Update 20190728: The OnProgressReport function is inherited from the superclass.

  0 Comments

Sign in to comment.

Products


Release

R2019a

1 Answer

Answer by Edric Ellis
on 26 Jul 2019
Edited by Edric Ellis
on 29 Jul 2019

EDIT: Changed my version to inherit protected method from parent class
Hm, I can't reproduce the problem - I tried in R2016b and R2019a. Here are my test classes:
%% Super.m:
classdef Super
properties (Access = private)
Value = 7
end
methods (Access = protected)
function out = protectedMethod(obj, x)
out = obj.Value + x;
end
end
end
%% Test.m:
classdef Test < Super
methods
function out = runInParfor(obj)
parfor ii = 1:4
out(ii) = obj.protectedMethod(ii);
end
end
end
end
which I exercise like this:
>> runInParfor(Test)
ans =
8 9 10 11
So, it appears to work for me. Could you elaborate on what you're doing differently?

  3 Comments

Sorry my description has some mistakes. That protected function is inherited from the superclass. Please try again thanks!
Ok, I updated my attempt to reproduce the problem, still works fine for me...
Well I got it. The exception details showed in the commandline window is misleading - it said that the OnProgressReport function is undefined, but the real bug I found later has nothing to do with that function. So tricky! Whatever thank you for your patience.

Sign in to comment.