Re: speed of fread in octave

[Peter Cloetens]

We are using version 2.1.71.

The platform is Linux Suse 8.2 , Suse 9.0 or RHEL4 on Xeon or Opteron CPU's.

I didn't notice a significant difference between the different OS / cpu combinations.

We are calling fread inside functions and scripts, but even in its simplest form the speed difference is obvious.

I would not call it a bug, but a performance issue.

For example:

in octave:

address@hidden:PZ> fid=fopen('ref0000_0000.edf','rb');

address@hidden:PZ> readedfheader(fid);

address@hidden:PZ> tic;fread(fid,1748*2048,'uint16');toc

ans = 0.53232

in matlab:

>> fid=fopen('ref0001_0000.edf','rb');

>> readedfheader(fid);

>> tic;fread(fid,1748*2048,'uint16');toc

Elapsed time is 0.049493 seconds.

Thanks,

Peter

 

On Jun 13, 2006, at 7:48 PM, John W. Eaton wrote:

On 13-Jun-2006, Peter Cloetens wrote:

| I start to use Octave for many things (if not all) instead of Matlab.

| However, I noticed a significant difference in speed for the command  

| fread.

| Reading with Octave is rather fast (9 MB/s) but much slower than  

| Matlab: factor 3-4.

| Is there any way to read binary uint16 data faster into Octave?

| For many other things I noticed that Octave is actually faster than  

| Matlab (typically 20-30%).

What version of Octave are you using.  On what platform?  How was it

compiled?  Precisely how are you calling the fread function?

If you think you have found a bug in Octave, then please submit a

complete bug report to the address@hidden list.  If you aren't sure

what to include in the report so that it is useful, then please read

http://www.otave.org/bugs.html before sending your report.

jwe

Peter Cloetens

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