On Tue, Nov 11, 2008 at 9:13 PM, Melissa Lopez-Larson <[log in to unmask]> wrote:

Hello,

I am attempting to compare 2 subject groups in vbm and I wanted to add age as another
EV.  I demeaned the data and set my design matrix and design contrast but get the error
below.  I have tried to change my matrix many times in the GLM and can not figure out
what I am doing wrong.
Thanks,
Melissa

/NumWaves 2
/NumPoints 21
/PPheights 1 1
/Matrix
1       0       3.87    0
1       0       -0.63   0
1       0       3.26    0
1       0       2.75    0
1       0       -2.35   0
1       0       1.32    0
1       0       -1.41   0
1       0       0.79    0
1       0       -1.83   0
1       0       0.17    0
0.0     1.0     0       2.63
0.0     1.0     0       3.55
0.0     1.0     0       -3.76
0.0     1.0     0       -2.37
0.0     1.0     0       -0.59
0.0     1.0     0       -1.37
0.0     1.0     0       1.24
0.0     1.0     0       -1.99
0.0     1.0     0       -0.41
0.0     1.0     0       0.67
0.0     1.0     0       -1.83



and my design.con as:
/NumWaves 2
/NumContrasts 4
/PPheights 1 1
/Matrix
1       0       0       0
0       1.0     0       0
1.0     -1.0    0       0
-1.0    1.0     0       0


However, I get the following error after the permutation have run:

An exception has been thrown
Runtime error:- detected by Newmat: matrix is singular

MatrixType = Crout  # Rows = 2; # Cols = 2
Trace: Crout(lubksb); GeneralSolvI; InvertedMatrix::Evaluate.