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Bug 3203 - ft_headmodel_localspheres incompatible with spatial projectors ?

Reported 2016-11-04 21:24:00 +0100
Modified 2017-03-14 12:48:31 +0100
Product: FieldTrip
Component: forward
Version: unspecified
Hardware: PC
Operating System: Windows
Importance: P5 major
Assigned to: Jan-Mathijs Schoffelen
Depends on:
See also:

Fran├žois Tadel - 2016-11-04 21:24:35 +0100

Hello, I'm writing a Brainstorm wrapper for ft_prepare_headmodel. It works well for singlesphere and singleshell, but I don't understand what I'm supposed to do with localspheres. I'm passing a grad structure with a .tra matrix that includes multiple transformation matrices (the CTF 3rd order gradient compensation + a few SSP projectors). By construction this .tra matrix has almost no zero values. In this configuration, line 138 behaves in really weird way: Am I missing something, or is it that this function is incompatible with this type of input? Thanks Francois

Jan-Mathijs Schoffelen - 2016-11-29 09:14:48 +0100

It looks as if the code for the localspheres has not evolved along with the rest of the code-base. Once upon a time, we only used unbalanced gradiometer definitions, and this particular line worked well to identify the coils that contribute to a particular gradiometer. I suspect that with the current state of the code, we may need to use chanori and chanpos instead.

Jan-Mathijs Schoffelen - 2017-01-23 14:00:23 +0100

Pull request #304 on should take care of this now.