[Octave-bug-tracker] [bug #33680] System stalled by using 'strread'

[anonymous]

URL:
  <http://savannah.gnu.org/bugs/?33680>

                 Summary: System stalled by using  'strread' 
                 Project: GNU Octave
            Submitted by: None
            Submitted on: Do 30 Jun 2011 15:21:31 UTC
                Category: Libraries
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Performance
                  Status: None
             Assigned to: None
         Originator Name: 
        Originator Email: address@hidden
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 3.4.2
        Operating System: GNU/Linux

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Details:

The routine 'strread' the function in line 244

[~, ~, ~, out] = regexp (text, pat);

is extrem memory consuming. The memory will reservated until octave is closed.
Big files over 14MB will lead to
a running out of memory failure of a system with 1GB RAM.

The History:

I use 

+varbatim+
textread[Z(:,1),Z(:,2),Z(:,4),Z(:,3)]=textread('File.txt','%f %f %f
%f','headerlines',11)


The File.txt is 14 MB large. I found that regexp is the origin of the problem.
After 'regexp' started the system stalled.

The command "whos" in octave shows a normal memory usage of the big input
files, but while the 'strread' routine is running the machine memory filled up
until the harddrive SWAP starts.The complete system hang up and over an hour
later octave ends with a memory failure message. 

I have rewrite the 'strread' to avoid 'regexp', but this routine functioning
only for my files.
An example of my file you are attached on this posting.
In order to run this file, you need the command:
+varbatim+
[Ct(:,2),Ct(:,1), tmp]=textread_cm('110527kali_t.txt','%f %f
%f','headerlines',10);

and the two rewritten octave files.

Thanks for help!







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File Attachments:


-------------------------------------------------------
Date: Do 30 Jun 2011 15:21:32 UTC  Name: 110527kali_t.txt  Size: 1kB   By:
None

<http://savannah.gnu.org/bugs/download.php?file_id=23593>
-------------------------------------------------------
Date: Do 30 Jun 2011 15:21:32 UTC  Name: strread_cm.m  Size: 9kB   By: None

<http://savannah.gnu.org/bugs/download.php?file_id=23594>
-------------------------------------------------------
Date: Do 30 Jun 2011 15:21:32 UTC  Name: textread_cm.m  Size: 3kB   By: None

<http://savannah.gnu.org/bugs/download.php?file_id=23595>

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