new implementation of mtmconvol and mtmfft: specest

[Roemer van der Meij]

Dear subscribers,

As of today, we have switched to a new implementation for the
'mtmconvol' and 'mtmfft' methods for frequency analysis. For a while now
we have been rewriting the low-level code in a different format, one
that is more flexible to adapt in the future and that allows for the
low-level algorithms to be downloaded in a separate module: /specest/.
The changes will be on our ftp-server by tonight.

The switch to the new implementation brings about several changes. With
respect to the changes are observable to the end-user, there are several
FAQs created at our wiki.

For the end-user observable changes for 'mtmconvol', please have a look
/here/
<http://fieldtrip.fcdonders.nl/faq/what_are_the_differences_between_the_old_and_the_new_implementation_of_mtmconvol_in_ft_freqanalyis>,
and for a bigger description with respect to your output.freq please go
/here/
<http://fieldtrip.fcdonders.nl/faq/why_does_my_output.freq_not_match_my_cfg.foi_when_using_mtmconvol_in_ft_freqanalyis>.

For the end-user observable changes for 'mtmfft', please have a look
/here/
<http://fieldtrip.fcdonders.nl/faq/what_are_the_differences_between_the_old_and_the_new_implementation_of_mtmfft_in_ft_freqanalyis>.

Because of these changes, it is advisable to either use the new or the
old implementation for your entire analysis project. We strongly advise
against combining or comparing data that have in part been produced by
the new implementation and in part by the old implementation, especially
when using phase information. The old implementation is still available
by using 'mtmconvol_old' or 'mtmfft_old' as cfg.method. However, this
code is deprecated and is no longer being updated. One can call also
call the function: ft_freqanalysis_old, which is the old interface-function.

If you are interested, you can track the progress of the /specest
/module by going /here/
<http://fieldtrip.fcdonders.nl/development/specest>. As soon as the
other low-level functions are ready and implemented, another e-mail will
be sent to the mailing-list.

If anything is unclear, or if there are any bugs that have slipped
through our fingers, please send an e-mail to the mailing-list and/or
report a bug in our /Bugzilla bug tracking system
<http://fieldtrip.fcdonders.nl/bugzilla>/.

Kind regards,

Roemer van der Meij


--
Roemer van der Meij MSc
PhD student
Donders Institute for Brain, Cognition and Behaviour
Centre for Cognition
P.O. Box 9104
6500 HE Nijmegen
The Netherlands
Tel: +31(0)24 3655932
E-mail: r.vandermeij at donders.ru.nl

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