problem on wavelet analysis, combine channel

alotof eve alotof_xd at YAHOO.COM
Fri Mar 30 15:49:35 CEST 2007


Dear Jan and Nathan,

      Thank you so much. But I am 80 percent sure it's not a common memory problem. My computer is 1GB of RAM. And if I don't use combination, I can select very fine parameters for wavelet analysis. My data is neuromag .fif data. I suppose something wrong with the channel counting.
      Thanks.

  Best,
  eve

Jan Mathijs Schoffelen <Jan.Schoffelen at FCDONDERS.RU.NL> wrote:
  Dear Eve,

I totally agree with Nathan. Specifying (unintended, but still... ;o) )
'powandcsd', in particular in combination with a spectro-temporal
reconstruction really blows up your memory requirements. Especially when
(again probably unintended) you are computing csd's for all
channelcombination. I'll leave it up to you to calculate how many bytes are
needed only to represent your output csd-matrix in memory.
Some hints:
-each double precision number requires 8 bytes of memory in matlab
-each complex number consists of two double precision numbers
-(numberoftrials)x(numberofchannelcombinations)x(numberoffrequencypoints)x
(numberoftimepoints) can become really big.

Yours,

Jan-Mathijs

-----Original Message-----
From: FieldTrip discussion list [mailto:FIELDTRIP at NIC.SURFNET.NL] On Behalf
Of Nathan Weisz
Sent: Friday, March 30, 2007 9:31 AM
To: FIELDTRIP at NIC.SURFNET.NL
Subject: Re: [FIELDTRIP] problem on wavelet analysis, combine channel

hi eve,

i'm not too familiar with the fieldtrip specifications, but:

> Out of memory. Type HELP MEMORY for your options.

do you have enough RAM?

this would then not be a real fieldtrip problem, but a rather common
problem generally when using matlab.

good luck!

nathan



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