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Bug 773 - ft_compute_leadfield: cfg.pos as Nx3 and reducerank='yes' gives wrong results

Reported 2011-06-21 12:13:00 +0200
Modified 2011-06-22 13:44:10 +0200
Product: FieldTrip
Component: forward
Version: unspecified
Hardware: PC
Operating System: Windows
Importance: P1 normal
Assigned to: Johanna
Depends on:
See also:

Johanna - 2011-06-21 12:13:51 +0200

If reducerank='yes', then svd of 'lf' is done. If Ndipoles = 1, then this is svd of a matrix sized nchan*3. If Ndipoles >1, then svd of nchan*(3*Ndipoles) matrix, which is the incorrect computation. Most calls to ft_compute_leadfield by other FT code (e.g. ft_prepare_leadfield or ft_dipolesimulation) are either for-loops over pos, or have reducerank='no', hence not a problem. But I found a few which seem to allow the option of Nx3 and reducerank specified by user: beamformer_pcc.m (for refdip and supdip) beamformer_dics.m (for refdip) beamformer_sam.m (for vox_pos) dipole_fit.m (for pos) Or if the user calls ft_compute_leadfield directly.