[Octave-bug-tracker] [bug #55296] Package "parallel": Issue with parcellfun after update

[anonymous]

URL:
  <https://savannah.gnu.org/bugs/?55296>

                 Summary: Package "parallel": Issue with parcellfun after
update
                 Project: GNU Octave
            Submitted by: None
            Submitted on: Thu 27 Dec 2018 01:02:34 PM UTC
                Category: Octave Forge Package
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Unexpected Error
                  Status: None
             Assigned to: None
         Originator Name: Michael Rackl
        Originator Email: address@hidden
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 4.2.2
        Operating System: GNU/Linux

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Details:

Hello,

we am maintaining a code package for simulation parameter calibration on
GitHub (https://github.com/DECALIOC/DEcalioc).

PROBLEM STATEMENT

We have to run a set of parameters on a model. We want run multiple processes
in parallel, where each process could require more than one CPU core. The
function we call with parcellfun calls a batch script for each process (which
needs 1 to N CPU cores) and also collects the results to feed them back to
parcellfun.

ISSUE

The code used to run under parallel version 3.1.1. However, with version
3.1.3, there appear to have been made changes that cause our code to fail with
the error:

"can't reshape 2x21 array to 1x13 array
parcellfun at line 452 column 21
DEcalioc at line 94 column 18"

I have attached the state after the code fails in a MAT file, where "runs_all"
does not seem to match up with the result cell returned from parcellfun.

FINDINGS so far

For different ncpu values, the error message changes:
ncpu = 8

error: reshape: can't reshape 2x21 array to 1x13 array
error: called from
    parcellfun at line 452 column 21
    DEcalioc at line 94 column 18

ncpu = 4

error: reshape: can't reshape 2x21 array to 1x5 array
error: called from
    parcellfun at line 452 column 21
    DEcalioc at line 94 column 18

ncpu = 1

parcellfun: 1/1 jobs done
parcellfun: waiting for child process 13621 to close
error: reshape: can't reshape 2x21 array to 1x1 array
error: called from
    parcellfun at line 452 column 21
    DEcalioc at line 94 column 18



SYSTEM SPECIFICATIONS

Octave 4.2.2
Ubuntu 18.04.1 LTS
64bit

>> pkg list
Package Name  | Version | Installation directory
--------------+---------+-----------------------
          io *|  2.4.12 | /home/michael/octave/io-2.4.12
       optim *|   1.5.3 | /home/michael/octave/optim-1.5.3
    parallel *|   3.1.3 | /home/michael/octave/parallel-3.1.3
  statistics *|   1.4.0 | /home/michael/octave/statistics-1.4.0
         stk *|   2.5.1 | /home/michael/octave/stk-2.5.1
      struct *|  1.0.15 | /home/michael/octave/struct-1.0.15



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File Attachments:


-------------------------------------------------------
Date: Thu 27 Dec 2018 01:02:34 PM UTC  Name: Files.zip  Size: 2KiB   By: None

<http://savannah.gnu.org/bugs/download.php?file_id=45747>

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