Hi,
this is a memory allocation problem - can you confirm what platform
you're running this on (32bit intel?). Also, it would be helpful to
get some info about the amount of memory and the size of the data set
(after unzip) as well as th size info (number of vols and voxels). If
you want to upload the data at http://www.fmrib.ox.ac.uk/cgi-bin/
upload.cgi I'll have a look and see if masking or avwroi might help
(please don't forget sending me the upload ID!)
cheers
christian
On 13 May 2006, at 23:32, Giuseppe Pagnoni wrote:
> Hi Christian,
>
> I haven't figured out how to make melodic work with the bigger
> dataset I
> have, but the ICA (not PCA) of the concatenated IC maps looks
> impressive:
> the maps are anatomically well-defined and match very well with the
> ones you
> reported in your paper.
>
> I had tried also another approach, clustering the spatial
> correlation matrix
> between pairs of individual IC maps, but the ICA^2 (!) approach
> seem to do a
> much better job.
>
> Thanks for all your suggestions, and if you happen to find out how
> to avoid
> the bad_alloc error please let me know (I would like to see whether
> those
> RSNs replicate or change in my treatment sample...)
>
> very best
>
> giuseppe
>
>
>
>
> On Wed, 10 May 2006 23:29:24 +0100, Giuseppe Pagnoni
> <[log in to unmask]> wrote:
>
>> Hi Christian,
>>
>> thank you very much for your reply. I tried your suggestion, and
>> while it
>> works on the smaller of two datasets (a *.nii.gz file of ~ 26 MB),
>> it throws
>> an alloc error when using a larger dataset (a *.nii.gz file of ~
>> 37 MB):
>>
>> Melodic Version ln(12) beta
>>
>> Melodic results will be in run2.IC.cat.MEDT.ica
>>
>> Reading data file run2.IC.cat.MEDT ... done
>> Create mask ... done
>> Excluding voxels with constant value
>> terminate called after throwing an instance of 'std::bad_alloc'
>> what(): St9bad_alloc
>> Abort
>>
>> Is this a known memory limitation of melodic? I tried it both on
>> a FreeBSD
>> machine and a Fedora 5 machine, with the same result.
>>
>> thanks again for your help
>>
>> giuseppe
>> =====================================================================
>> ====
--
Christian F. Beckmann
Oxford University Centre for Functional
Magnetic Resonance Imaging of the Brain,
John Radcliffe Hospital, Headington, Oxford OX3 9DU, UK
Email: [log in to unmask] - http://www.fmrib.ox.ac.uk/~beckmann/
Phone: +44(0)1865 222551 Fax: +44(0)1865 222717
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