Parfor 循环在执行第一组迭代后重新启动

Question

我在执行 parfor 循环的脚本中遇到问题，希望您能帮我解决。

我以前没有遇到过这个问题，我想我没有更改任何可能导致它的东西。

问题在于 parfor 循环在启动具有 4 个工作人员的并行组并执行前 4 次迭代后重新启动。这发生一次，然后正常执行所有迭代。

这是我的代码，为了显示这个问题而进行了简化：

parfor loopVariable = 1 : 21
    fprintf('%s - Running iteration %i/%i \n', datestr(datetime), loopVariable, 21)
    *statements*
end

这是我得到的输出，你会注意到前 4 次迭代是重复的：

Starting parallel pool (parpool) using the 'local' profile ...
connected to 4 workers.
04-May-2020 11:43:21 - Running iteration 1/21
04-May-2020 11:43:21 - Running iteration 2/21
04-May-2020 11:43:21 - Running iteration 4/21
04-May-2020 11:43:21 - Running iteration 7/21

Analyzing and transferring files to the workers ...done.

04-May-2020 15:01:12 - Running iteration 7/21
04-May-2020 15:01:12 - Running iteration 1/21
04-May-2020 15:01:12 - Running iteration 2/21
04-May-2020 15:01:12 - Running iteration 4/21
04-May-2020 15:24:29 - Running iteration 3/21
04-May-2020 16:21:16 - Running iteration 6/21
04-May-2020 16:12:52 - Running iteration 13/21
04-May-2020 16:20:32 - Running iteration 10/21
04-May-2020 18:34:27 - Running iteration 12/21
04-May-2020 18:39:20 - Running iteration 9/21
04-May-2020 20:33:04 - Running iteration 5/21
04-May-2020 20:50:08 - Running iteration 11/21
04-May-2020 21:07:43 - Running iteration 8/21
04-May-2020 22:42:34 - Running iteration 15/21
05-May-2020 01:09:18 - Running iteration 14/21
04-May-2020 23:05:16 - Running iteration 18/21
04-May-2020 23:53:35 - Running iteration 19/21
05-May-2020 01:50:12 - Running iteration 17/21
05-May-2020 04:40:23 - Running iteration 16/21
05-May-2020 01:52:47 - Running iteration 21/21
05-May-2020 03:34:10 - Running iteration 20/21

我不知道这是否相关，但我正在远程运行脚本：

nohup matlab -nodisplay -nosplash  -r scriptFile -logfile outputFile.txt < /dev/null &

提前感谢您的帮助。

Answer 1

您显示的代码段是正确的。您确定不是代码的其他部分或*statements* 的某些部分吗？

>> parfor loopVariable = 1 : 21
    fprintf('%s - Running iteration %i/%i \n', datestr(datetime), loopVariable, 21)
   end
Starting parallel pool (parpool) using the 'local' profile ...
Connected to the parallel pool (number of workers: 4).
05-May-2020 11:10:56 - Running iteration 1/21 
05-May-2020 11:10:56 - Running iteration 6/21 
05-May-2020 11:10:56 - Running iteration 5/21 
05-May-2020 11:10:56 - Running iteration 15/21 
05-May-2020 11:10:56 - Running iteration 19/21 
05-May-2020 11:10:56 - Running iteration 2/21 
05-May-2020 11:10:56 - Running iteration 8/21 
05-May-2020 11:10:56 - Running iteration 7/21 
05-May-2020 11:10:56 - Running iteration 13/21 
05-May-2020 11:10:56 - Running iteration 17/21 
05-May-2020 11:10:56 - Running iteration 3/21 
05-May-2020 11:10:56 - Running iteration 10/21 
05-May-2020 11:10:56 - Running iteration 9/21 
05-May-2020 11:10:56 - Running iteration 14/21 
05-May-2020 11:10:56 - Running iteration 18/21 
05-May-2020 11:10:56 - Running iteration 4/21 
05-May-2020 11:10:56 - Running iteration 12/21 
05-May-2020 11:10:56 - Running iteration 11/21 
05-May-2020 11:10:56 - Running iteration 16/21 
05-May-2020 11:10:56 - Running iteration 21/21 
05-May-2020 11:10:56 - Running iteration 20/21