[FieldTrip] Two versions of matlab yield different output from runica

Carmen Kung carmen.kung at mq.edu.au
Mon Jul 20 04:16:48 CEST 2015


Dear Roey and Jorn,

Thank you very much for your suggestions.
Roey, I have run ft_componentanalysis twice using the same version of 
Matlab (was by chance running the script twice though).  The analyses 
yielded the almost identical results (still very slight difference).
J ├Ârn,  thank you very much for the tip. The same (almost identical) 
results turn up after assigning the same random seed number in the two 
different versions of Matlab.

Cheers,
Carmen

On 16/07/2015 8:00 PM, fieldtrip-request at science.ru.nl wrote:
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>     1. Two versions of matlab yield different output from	runica
>        (Carmen Kung)
>     2. Re: Two versions of matlab yield different output from	runica
>        (Roey Schurr)
>     3. Re: Two versions of matlab yield different output	from	runica
>        (=?utf-8?Q?J=C3=B6rn_M._Horschig?=)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Thu, 16 Jul 2015 18:05:48 +1000
> From: Carmen Kung <carmen.kung at mq.edu.au>
> To: fieldtrip at science.ru.nl
> Subject: [FieldTrip] Two versions of matlab yield different output
> 	from	runica
> Message-ID: <55A765DC.1020207 at mq.edu.au>
> Content-Type: text/plain; charset=utf-8; format=flowed
>
> Dear fellow fieldtrippers,
>
> A colleauge and I are analysing the same set of EEG data using the same
> fieldtrip toolbox (the version of 20150522) but we have different
> versions of matlab installed on each of our computer (mine is 2013b and
> hers is 2014b).  After running  ft_componentanalysis (using runica), we
> compared the output between us and we found that ft_componentanalysis
> yielded mostly the same components but still there are differences in
> ranking and the output.
>
> Does anyone know why this is the case and suggest which Matlab version
> we should use
>
> Many thanks in advance,
> Carmen
>
>
> ------------------------------
>
> Message: 2
> Date: Thu, 16 Jul 2015 11:15:26 +0300
> From: Roey Schurr <roeysc at gmail.com>
> To: FieldTrip discussion list <fieldtrip at science.ru.nl>
> Subject: Re: [FieldTrip] Two versions of matlab yield different output
> 	from	runica
> Message-ID:
> 	<CAHm4wZByE1UuybV=+MsbVbCJDSJEm0s=ycAZGaUN9aZ6G51WrA at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> Dear Carmen,
> have you tried running ft_componentanalysis twice on the same matlab? The
> ICA algorithm has some intrinsic stochasticity in it, and therefore even
> running it twice on one machine and one matlab version should yield similar
> but not identical results.
> I hope this is indeed the case, and that I'm not misleading you.
> Best,
> Roey
>
> On Thu, Jul 16, 2015 at 11:05 AM, Carmen Kung <carmen.kung at mq.edu.au> wrote:
>
>> Dear fellow fieldtrippers,
>>
>> A colleauge and I are analysing the same set of EEG data using the same
>> fieldtrip toolbox (the version of 20150522) but we have different versions
>> of matlab installed on each of our computer (mine is 2013b and hers is
>> 2014b).  After running  ft_componentanalysis (using runica), we compared
>> the output between us and we found that ft_componentanalysis yielded mostly
>> the same components but still there are differences in ranking and the
>> output.
>>
>> Does anyone know why this is the case and suggest which Matlab version we
>> should use
>>
>> Many thanks in advance,
>> Carmen
>> _______________________________________________
>> fieldtrip mailing list
>> fieldtrip at donders.ru.nl
>> http://mailman.science.ru.nl/mailman/listinfo/fieldtrip
>>
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> ------------------------------
>
> Message: 3
> Date: Thu, 16 Jul 2015 10:27:52 +0200
> From: "=?utf-8?Q?J=C3=B6rn_M._Horschig?=" <jorn at artinis.com>
> To: "'FieldTrip discussion list'" <fieldtrip at science.ru.nl>
> Subject: Re: [FieldTrip] Two versions of matlab yield different output
> 	from	runica
> Message-ID: <006f01d0bfa1$4f023910$ed06ab30$@artinis.com>
> Content-Type: text/plain; charset="utf-8"
>
> Dear Roey,
>
>   
>
> that is indeed true. ICA (at least most versions like runica) use some random initialization of the weights, which is realized by using a random number generator. You can set the random seed manually in FieldTrip/EEGLAB to verify whether you get the same results for different Matlab versions (as long as the algorithms for the random number generator has not changed). Not sure if results will be same across different operating systems though.
>
>   
>
> Best,
>
> J?rn
>
>   
>
> PS: I vaguely remembered some bug in EEGLAB (which?s algorithm FieldTrip uses), so I looked it up on Bugzilla: http://bugzilla.fieldtriptoolbox.org/show_bug.cgi?id=2585 so that one seems to be resolved.
>
>   
>
> --
>
>   
>
> J?rn M. Horschig, PhD, Software Engineer
>
>   <http://www.artinis.com/> Artinis Medical Systems  |  +31 481 350 980
>
>   
>
> From: fieldtrip-bounces at science.ru.nl [mailto:fieldtrip-bounces at science.ru.nl] On Behalf Of Roey Schurr
> Sent: Thursday, July 16, 2015 10:15 AM
> To: FieldTrip discussion list
> Subject: Re: [FieldTrip] Two versions of matlab yield different output from runica
>
>   
>
> Dear Carmen,
>
> have you tried running ft_componentanalysis twice on the same matlab? The ICA algorithm has some intrinsic stochasticity in it, and therefore even running it twice on one machine and one matlab version should yield similar but not identical results.
>
> I hope this is indeed the case, and that I'm not misleading you.
>
> Best,
>
> Roey
>
>   
>
> On Thu, Jul 16, 2015 at 11:05 AM, Carmen Kung <carmen.kung at mq.edu.au <mailto:carmen.kung at mq.edu.au> > wrote:
>
> Dear fellow fieldtrippers,
>
> A colleauge and I are analysing the same set of EEG data using the same fieldtrip toolbox (the version of 20150522) but we have different versions of matlab installed on each of our computer (mine is 2013b and hers is 2014b).  After running  ft_componentanalysis (using runica), we compared the output between us and we found that ft_componentanalysis yielded mostly the same components but still there are differences in ranking and the output.
>
> Does anyone know why this is the case and suggest which Matlab version we should use
>
> Many thanks in advance,
> Carmen
> _______________________________________________
> fieldtrip mailing list
> fieldtrip at donders.ru.nl <mailto:fieldtrip at donders.ru.nl>
> http://mailman.science.ru.nl/mailman/listinfo/fieldtrip
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