Parfor Error Handling results in falsely reported error in each loop

Question

Thomas Förster 2017-9-8

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/355734-parfor-error-handling-results-in-falsely-reported-error-in-each-loop

回答： Thomas Förster 2017-9-9

Hello, I have a problem regarding parfor loops. I try to solve an array of pdeobjects, that all have a different partly different geometry. Since for some of those geometries the pdenonlin solver doesnt find a solution ( -> Step size to small, to many iterations) I tried using an error handle:

Torque=zeros(1,(length(sCalc.angle)-1));
Error=zeros(1,(length(sCalc.angle)-1));
parfor i=1:1:(length(sCalc.angle)-1)
  try
    results = solvepde(sMotor(i));
    Torque(i)=getTorque2(results);
    result(i)=results;
    Error(i)=0;
  catch
    Error(i)=1;
  end
end

This works for a normal for:

Error 0 0 0 0 1 0

But when using parfor, even though it doesnt fail I get an Error for each loop:

Error 1 1 1 1 1 1

What am I doing wrong?

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

OCDER 2017-9-8

在 MATLAB Online 中打开

Not sure because we don't know what these are: sCalc, sMotor, solvepde, and getTorque2. But instead of catching your Error in a matrix, try to display the error message in the catch statement. That may reveal the error source.

Torque=zeros(1,(length(sCalc.angle)-1));
Error=zeros(1,(length(sCalc.angle)-1));
parfor i=1:1:(length(sCalc.angle)-1)
  try
    results = solvepde(sMotor(i));
    Torque(i)=getTorque2(results);
    result(i)=results;
    Error(i)=0;
  catch ME
    disp(ME.message); %Will show the error info
    Error(i)=1;
  end
end

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Thomas Förster 2017-9-9

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/355734-parfor-error-handling-results-in-falsely-reported-error-in-each-loop#answer_280883

在 MATLAB Online 中打开

Well, rookie mistake on my part, doing it like this it works. Would recommend to not use pde arrays in the way that I use them, since they need a lot of memory!

Works like this:

Torque=zeros(1,(length(sCalc.angle)-1));
Error=zeros(1,(length(sCalc.angle)-1));
result(length(sCalc.angle)-1)=pde.StationaryResults;
parfor i=1:1:(length(sCalc.angle)-1)
  try
    result(i) = solvepde(sMotor(i));
    Torque(i)=getTorque2(result(i));
    Error(i)=0;
  catch
    Error(i)=1;
  end
end