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pr_spm_orth

PURPOSE

recursive orthogonalization of basis functions

SYNOPSIS

function x = spm_orth(X)

DESCRIPTION

 recursive orthogonalization of basis functions
 FORMAT x = spm_orth(X)

 serial orthogionalization starting with the first column
_______________________________________________________________________
 @(#)spm_orth.m    2.1 Karl Friston 02/02/07

CROSS-REFERENCE INFORMATION

This function calls:

This function is called by:

pr_spm_get_bf fills in basis function structure
pr_spm_get_ons returns input [designed effects] structures
pr_fmri_design MarsBaR version of spm_fMRI design - asssembles a design for fMRI studies
pr_spm_get_bf fills in basis function structure
pr_spm_get_ons returns input [designed effects] structures
event_x_fir method to return FIR design matrix columns for session
pr_spm_get_bf creates basis functions for each trial type {i} in struct BF{i}

SOURCE CODE

0001 function x = spm_orth(X)
0002 % recursive orthogonalization of basis functions
0003 % FORMAT x = spm_orth(X)
0004 %
0005 % serial orthogionalization starting with the first column
0006 %_______________________________________________________________________
0007 % @(#)spm_orth.m    2.1 Karl Friston 02/02/07
0008 
0009 x     = X(:,1);
0010 for i = 2:size(X,2)
0011         D     = X(:,i);
0012         D     = D - x*(pinv(x)*D);
0013         if any(D)
0014                 x = [x D];
0015         end
0016 end
0017