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[Octave-bug-tracker] [bug #54100] fread using SKIP larger than zero is e
From: |
anonymous |
Subject: |
[Octave-bug-tracker] [bug #54100] fread using SKIP larger than zero is extremely slow |
Date: |
Mon, 11 Jun 2018 14:41:32 -0400 (EDT) |
User-agent: |
Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:60.0) Gecko/20100101 Firefox/60.0 |
URL:
<http://savannah.gnu.org/bugs/?54100>
Summary: fread using SKIP larger than zero is extremely slow
Project: GNU Octave
Submitted by: None
Submitted on: Mon 11 Jun 2018 06:41:30 PM UTC
Category: Octave Function
Severity: 3 - Normal
Priority: 5 - Normal
Item Group: Performance
Status: None
Assigned to: None
Originator Name: Gisle J Torvetjonn
Originator Email: address@hidden
Open/Closed: Open
Discussion Lock: Any
Release: 4.4.0
Operating System: Microsoft Windows
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Details:
data = single(fread(fid,[Var.no+1 nl],'single',0));
is quite speedy while
data = fread(fid,[Var.no nl],'single',4);
is very very very slow.
Reducing Var.no and increasing the number of skips increases the speed
data = fread(fid,[2 nl],'single',4*(Var.no-1));
takes 23.6 sec while
data = fread(fid,[1 nl],'single',4*(Var.no));
takes 11.6 sec while
data = single(fread(fid,[Var.no+1 nl],'single',0));
takes 0.2 sec.
(Var.no=60)
The code works fine in Matlab.
The code is intended for reading a double column in a mixed dataset . The
first row is 'double' and the rest is single.
_______________________________________________________
File Attachments:
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Date: Mon 11 Jun 2018 06:41:30 PM UTC Name: LTSpiceRaw_Fa.m Size: 5KiB By:
None
<http://savannah.gnu.org/bugs/download.php?file_id=44359>
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Reply to this item at:
<http://savannah.gnu.org/bugs/?54100>
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- [Octave-bug-tracker] [bug #54100] fread using SKIP larger than zero is extremely slow,
anonymous <=
- [Octave-bug-tracker] [bug #54100] fread using SKIP larger than zero is extremely slow, Dan Sebald, 2018/06/11
- [Octave-bug-tracker] [bug #54100] fread using SKIP larger than zero is extremely slow, Michael Leitner, 2018/06/12
- [Octave-bug-tracker] [bug #54100] fread using SKIP larger than zero is extremely slow, Dan Sebald, 2018/06/12
- [Octave-bug-tracker] [bug #54100] fread using SKIP larger than zero is extremely slow, Michael Leitner, 2018/06/13
- [Octave-bug-tracker] [bug #54100] fread using SKIP larger than zero is extremely slow, Michael Leitner, 2018/06/13
- [Octave-bug-tracker] [bug #54100] fread using SKIP larger than zero is extremely slow, Dan Sebald, 2018/06/13
- [Octave-bug-tracker] [bug #54100] fread using SKIP larger than zero is extremely slow, Dan Sebald, 2018/06/13
- [Octave-bug-tracker] [bug #54100] fread using SKIP larger than zero is extremely slow, John W. Eaton, 2018/06/13
- [Octave-bug-tracker] [bug #54100] fread using SKIP larger than zero is extremely slow, Dan Sebald, 2018/06/14