[Mne_analysis] using mne.chpi tools {Disarmed}

[Megan Schendel]

        External Email - Use Caution        

Hi there,
I'd like to play around with the head position information from some raw
fif files.  I have been using the maxfilter program to extract the head
position files (the 6 quaternion variables) for some of the data, and I've
been importing that using chpi.read_head_pos() and that works fine.  But I
also have some raw data that I'd like to use, but that is failing.
I can use the maxfilter gui to review the head positions, so I know the
data is there.
I am following the plot head positions tutorial
<https://secure-web.cisco.com/1j4hhJQeZQNept_VI5WYCPKzV2CuMc0RYCcGKcd1Ro_zuPEuL9UCRFXLY_39y972YhG9iNQht-fFyhBjZfvWJ4fmVKXzNSgOSLTbbxIphiU-6fJW9GJHxwlgWT6ooXTV1BYv9opnUtzUrzv7YmS9GtCXNvBBMy3HeRcIoCBP9zwsHJB9zvDvRT2Z8TjQLKSNra9TrkrW7c2jpTBhNIaNCW8WSuC7sPGmE_Fc3g09SMc76rwVpr6N9LuhlV1v9JPalCpTAJ4NWjvVzZVwaEYReIg/https%3A%2F%2Fmne.tools%2Fstable%2Fauto_tutorials%2Fpreprocessing%2Fplot_59_head_positions.html%23sphx-glr-auto-tutorials-preprocessing-plot-59-head-positions-py>
.
io.read_raw works fine, chpi.compute_chpi_amplitutdes works,
chpi.compute_chpi_locs seems to work, but then chpi.compute_head_pos I get
<ipython-input-88-83e389120352>:1: RuntimeWarning:     t=598.850:   0/4
good HPI fits, cannot determine the transformation (0.16, 0.21, 0.18, 0.18)!
and the array in the output dictionary is empty.
I am running mne 21.0  (it works on the old CentOS6.7 without the 3d
plotting. I have it working on Ubuntu for 3d visualisations, finally, if
you remember my other thread from a while ago).

Here are the commands I'm using:
            raw = concat.concat_func(activeSubject, task, data_path,
defhead, mc)
            chpi_amplitudes = mne.chpi.compute_chpi_amplitudes(raw)
            chpi_locs = mne.chpi.compute_chpi_locs(raw.info,
chpi_amplitudes)
            head_pos= mne.chpi.compute_head_pos(raw.info, chpi_locs,
verbose=True)
Any suggestions?  Would it be helpful if I shared a bit of data?
Thank you,
Megan

MEG Technician
The Mind Research Network
1101 Yale Blvd. NE
Albuquerque, New Mexico 87106
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mail.nmr.mgh.harvard.edu/pipermail/mne_analysis/attachments/20201210/e347c11b/attachment.html