<div dir="ltr">Dear Avi,<div><br></div><div style>I would suggest using eeglab 12.0.1.(something) or higher<br>or download eeglab filter plugin by Andreas Widmann.</div><div style>It is optimized for multi-threading, and does not filter<br>
'backwards' to retain correct phase but instead shifts<br>the signal by the filter delay - altogether it should be <br>much faster (in current eeglab versions Andreas' plugin <br>is the default filter).</div><div style>
<br></div><div style>Mikołaj</div></div><div class="gmail_extra"><br clear="all"><div>Pozdrawiam,<br>Mikołaj Magnuski</div>
<br><br><div class="gmail_quote">2013/6/9 Avi Lazarovits <span dir="ltr"><<a href="mailto:avila@post.bgu.ac.il" target="_blank">avila@post.bgu.ac.il</a>></span><br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="rtl"><div style="direction:ltr"><p><span style="font-size:10pt;line-height:115%;font-family:Arial,sans-serif">Hello,</span></p>
<p><span style="font-size:10pt;line-height:115%;font-family:Arial,sans-serif">I am using EEGlab to process
EEG recordings, and running low pass 100 Hz is very slow. I am looking for code modifications I can make to accelerate the running time, and also recommendation for optimal hardware specs for this process.</span></p>
<p><span style="font-size:10pt;line-height:115%;font-family:Arial,sans-serif">The files I process are
recordings of 66 channles @ 2KHz ~10 minutes long (1086734 samples) bug. I can’t
resample the files because I need high temporal resolution.</span></p>
<p style="margin-bottom:0.0001pt"><span style="font-size:10pt;font-family:Arial,sans-serif">I use
EEGlab version 11.0.3.1b, and run “firls” filter. I run the filter with the following command: </span></p>
<p style="margin-bottom:0.0001pt"><span style="font-size:12pt;font-family:'Times New Roman',serif">EEG = pop_eegfilt(
EEG, 0, 100, [], 0,0, 0, ‘firls’, 0);</span><span style="font-size:12pt;font-family:'Times New Roman',serif"></span></p>
<p><span style="font-size:10pt;line-height:115%;font-family:Arial,sans-serif">When I run this command I get the following message: </span></p>
<p style="margin-bottom:0.0001pt"><span style="font-size:12pt;font-family:'Times New Roman',serif">eegfilt() - performing
6144-point highpass filtering.</span></p>
<p style="margin-bottom:0.0001pt"><span style="font-size:12pt;font-family:'Times New Roman',serif">eegfilt() - highpass
transition band width is 0.2 Hz.</span></p>
<p><span style="font-size:10pt;line-height:115%;font-family:Arial,sans-serif"> </span></p>
<p><span style="font-size:10pt;line-height:115%;font-family:Arial,sans-serif">The computer I run the
processing on now is i5 3470 (4 cores@ 3.2 Ghz) with 4Gb RAM running windows 7 enterprise
64 bit and Matlab 2012a. </span></p>
<p><span style="font-size:10pt;line-height:115%;font-family:Arial,sans-serif">I tried running the same
process on an i7 extreme edition 3930k with 64Gb RAM system and it didn't
shorten the running time at all. I also tried running this filter on a
workstation with Xeon CPU and it shortened the running time, but not
significantly. I looked on the CPU monitor and found that it doesn’t use more
than 1 core, and that the maximal RAM memory usage during the processing was
about 6.5 Gb.</span></p>
<p><span style="font-size:10pt;line-height:115%;font-family:Arial,sans-serif">1.<span style="font-size:7pt;line-height:normal;font-family:'Times New Roman'"> </span></span><span dir="LTR"></span><span style="font-size:10pt;line-height:115%;font-family:Arial,sans-serif">I found that using SSD shortens the time
significantly, and therefore I assume that one of the big bottlenecks of this
processing is that the process is made on the hard disk and not on the RAM. Is
there a way to “make” Matlab use RAM instead of the hard drive? </span></p>
<p><span style="font-size:10pt;line-height:115%;font-family:Arial,sans-serif">2.<span style="font-size:7pt;line-height:normal;font-family:'Times New Roman'"> </span></span><span dir="LTR"></span><span style="font-size:10pt;line-height:115%;font-family:Arial,sans-serif">Are there code changes I can make in EEGlab’s
code to run this filter multithreaded so that the process will use all the
cores of my CPU? Is there any way to make this process on GPU? Will it accelerate the process more than using parallel computing of the CPU? </span></p>
<p><span style="font-size:10pt;line-height:115%;font-family:Arial,sans-serif"> </span></p>
<p><span style="font-size:10pt;line-height:115%;font-family:Arial,sans-serif">Thank you</span></p><span class="HOEnZb"><font color="#888888">
<p><span style="font-size:10pt;line-height:115%;font-family:Arial,sans-serif">Avi</span></p></font></span></div></div>
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