[Eeglablist] STUDY function being slower?

[Delorme, Arnaud]

Dear Shingo,

Yes, 20 minutes sounds extreme. The statistics are the same. However, since version 2019.0, EEGLAB stores the single trials by default - there are many advantages to doing that. So the files are longer to load. If you have an SSD (solid state drive) hard drive, the difference is barely noticeable. In fast, we spent a lot of time (and delayed the release by more than one year) because the data was not loading fast enough. By reengineering the functions that load data, we were able to speed them up dramatically. 

So, my advise is to use an SSD drives (SSD drives can be 50 to 100 times faster than regular hard drives).

Best wishes,

Arno

> On Nov 11, 2019, at 2:02 PM, 時本真吾 <tokimoto at mejiro.ac.jp> wrote:
> 
> Dear EEGLAB experts,
> 
> I have analyzed EEG data with EEGLAB, and I am deeply grateful for the developers. I cannot find an appropriate word for my gratitude.
> 
> I feel that the processes for statistical analysis have become slower. I usually examine the statistical difference in ERP, ERSP, ITC for electrodes and the cluster of ICs by cluster-based permutation tests. It was usual to wait for one minute or so when I commanded a presentation by STUDY function on EEGLAB ver14. However, when I tried the same command on EEGLAB 2019, I have to wait for over 20 minutes. I often examine the statistical difference in the topography for every 100 ms from 100 to 1000 ms latency by a batch file, and in this case I have to wait for one night. 
> 
> I understand that the file system has been changed in EEGLAB 2019 and that we do not have to re-precompute the data files for each condition in STUDY. However, the file sizes of daterp, datspec, and dattimef are huge. Is it generally true that a STUDY function requires a longer time than before? Thank you in advance.
> 
> ******************************************
> Shingo Tokimoto, Ph.D.
> in Linguistics and Psychology
> Department of Foreign Languages
> Mejiro University
> 4-31-1, Naka-Ochiai, Shinjuku, Tokyo,
> 161-8539, Japan
> tokimoto at mejiro.ac.jp
> ******************************************
> 
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