The last column in the matrix is all 0s. This means that there are no members of that group (PTSDPTSD-diagnostikKG).

doug =?iso-8859-1?Q?=22Br=FChl@nmr.mgh.harvard.edu wrote:

Hi to All,

I have come across a problem using qdec, specified below. What I am trying to do is to look for an interaction between two discrete variables (diagnostik and PTSD). It is my understanding that this appears to be a common problem. However, is there a way around it, such as conceptualizing the design matrix differently? And how could that be done?

Thanks,

Hannah

[LOE5145MAC:~/Borderline_2/subjects] bruehh01% lh-Avg-Intercept-thickness ----------------------- Does the average thickness differ from zero? 1.000 1.000 1.000 1.000;

lh-Diff-NonPTSD-PTSD-Intercept-thickness ----------------------- Does the average thickness, accounting for diagnostik, differ between NonPTSD and PTSD? 1.000 -1.000 1.000 -1.000;

lh-Diff-BPD-KG-Intercept-thickness ----------------------- Does the average thickness, accounting for PTSD, differ between BPD and KG? 1.000 1.000 -1.000 -1.000;

lh-X-PTSD-diagnostik-Intercept-thickness ----------------------- Is there a PTSD--diagnostik interaction in the mean thickness? 1.000 -1.000 -1.000 1.000;

ninputs = 49 Checking inputs nframestot = 49 Allocing output nframes = 49 Writing to /Users/bruehh01/Borderline_2/subjects/qdec/Untitled/y.mgh gdfReadHeader: reading /Users/bruehh01/Borderline_2/subjects/qdec/Untitled/qdec.fsgd WARNING: gdfReadV1: class PTSDPTSD-diagnostikKG is defined but not used. INFO: demeaning continous variables Continuous Variable Means (all subjects) Class Means of each Continuous Variable 1 PTSDNonPTSD-diagnostikBPD 2 PTSDPTSD-diagnostikBPD 3 PTSDNonPTSD-diagnostikKG 4 PTSDPTSD-diagnostikKG INFO: gd2mtx_method is dods Reading source surface /Users/bruehh01/Borderline_2/subjects/fsaverage/surf/lh.white reading group avg surface area 822 cm^2 from file Reading in average area /Users/bruehh01/Borderline_2/subjects/fsaverage/surf/lh.white.avg.area.mgh Number of vertices 163842 Number of faces 327680 Total area 65416.648438 AvgVtxArea 0.399267 AvgVtxDist 0.721953 StdVtxDist 0.195470

$Id: mri_glmfit.c,v 1.138.2.15 2009/07/27 17:43:10 greve Exp $ cwd /Users/bruehh01/Borderline_2/subjects cmdline mri_glmfit --y /Users/bruehh01/Borderline_2/subjects/qdec/Untitled/y.mgh --fsgd /Users/bruehh01/Borderline_2/subjects/qdec/Untitled/qdec.fsgd dods --glmdir /Users/bruehh01/Borderline_2/subjects/qdec/Untitled --surf fsaverage lh --label /Users/bruehh01/Borderline_2/subjects/fsaverage/label/lh.cortex.label --C /Users/bruehh01/Borderline_2/subjects/qdec/Untitled/contrasts/lh-Avg-Intercept-thickness.mat --C /Users/bruehh01/Borderline_2/subjects/qdec/Untitled/contrasts/lh-Diff-NonPTSD-PTSD-Intercept-thickness.mat --C /Users/bruehh01/Borderline_2/subjects/qdec/Untitled/contrasts/lh-Diff-BPD-KG-Intercept-thickness.mat --C /Users/bruehh01/Borderline_2/subjects/qdec/Untitled/contrasts/lh-X-PTSD-diagnostik-Intercept-thickness.mat sysname Darwin hostname LOE5145MAC.campus.fu-berlin.de machine i386 user bruehh01 FixVertexAreaFlag = 1 UseMaskWithSmoothing 1 OneSampleGroupMean 0 y /Users/bruehh01/Borderline_2/subjects/qdec/Untitled/y.mgh logyflag 0 usedti 0 FSGD /Users/bruehh01/Borderline_2/subjects/qdec/Untitled/qdec.fsgd labelmask /Users/bruehh01/Borderline_2/subjects/fsaverage/label/lh.cortex.label maskinv 0 glmdir /Users/bruehh01/Borderline_2/subjects/qdec/Untitled IllCondOK 0 DoFFx 0 Creating output directory /Users/bruehh01/Borderline_2/subjects/qdec/Untitled Loading y from /Users/bruehh01/Borderline_2/subjects/qdec/Untitled/y.mgh INFO: gd2mtx_method is dods Saving design matrix to /Users/bruehh01/Borderline_2/subjects/qdec/Untitled/Xg.dat Matrix condition is 1e+08 ERROR: matrix is ill-conditioned or badly scaled, condno = 1e+08 Possible problem with experimental design: Check for duplicate entries and/or lack of range of continuous variables within a class. 1.000 0.000 0.000 0.000; 1.000 0.000 0.000 0.000; 0.000 1.000 0.000 0.000; 1.000 0.000 0.000 0.000; 1.000 0.000 0.000 0.000; 1.000 0.000 0.000 0.000; 0.000 1.000 0.000 0.000; 0.000 1.000 0.000 0.000; 1.000 0.000 0.000 0.000; 0.000 1.000 0.000 0.000; 0.000 1.000 0.000 0.000; 1.000 0.000 0.000 0.000; 1.000 0.000 0.000 0.000; 1.000 0.000 0.000 0.000; 0.000 1.000 0.000 0.000; 1.000 0.000 0.000 0.000; 0.000 1.000 0.000 0.000; 0.000 1.000 0.000 0.000; 1.000 0.000 0.000 0.000; 0.000 1.000 0.000 0.000; 0.000 1.000 0.000 0.000; 1.000 0.000 0.000 0.000; 1.000 0.000 0.000 0.000; 0.000 1.000 0.000 0.000; 1.000 0.000 0.000 0.000; 0.000 1.000 0.000 0.000; 1.000 0.000 0.000 0.000; 0.000 1.000 0.000 0.000; 0.000 1.000 0.000 0.000; 0.000 0.000 1.000 0.000; 0.000 0.000 1.000 0.000; 0.000 0.000 1.000 0.000; 0.000 0.000 1.000 0.000; 0.000 0.000 1.000 0.000; 0.000 0.000 1.000 0.000; 0.000 0.000 1.000 0.000; 0.000 0.000 1.000 0.000; 0.000 0.000 1.000 0.000; 0.000 0.000 1.000 0.000; 0.000 0.000 1.000 0.000; 0.000 0.000 1.000 0.000; 0.000 0.000 1.000 0.000; 0.000 0.000 1.000 0.000; 0.000 0.000 1.000 0.000; 0.000 0.000 1.000 0.000; 0.000 0.000 1.000 0.000; 0.000 0.000 1.000 0.000; 0.000 0.000 1.000 0.000; 0.000 0.000 1.000 0.000; Error in Analyze: command failed: mri_glmfit --y /Users/bruehh01/Borderline_2/subjects/qdec/Untitled/y.mgh --fsgd /Users/bruehh01/Borderline_2/subjects/qdec/Untitled/qdec.fsgd dods --glmdir /Users/bruehh01/Borderline_2/subjects/qdec/Untitled --surf fsaverage lh --label /Users/bruehh01/Borderline_2/subjects/fsaverage/label/lh.cortex.label --C /Users/bruehh01/Borderline_2/subjects/qdec/Untitled/contrasts/lh-Avg-Intercept-thickness.mat --C /Users/bruehh01/Borderline_2/subjects/qdec/Untitled/contrasts/lh-Diff-NonPTSD-PTSD-Intercept-thickness.mat --C /Users/bruehh01/Borderline_2/subjects/qdec/Untitled/contrasts/lh-Diff-BPD-KG-Intercept-thickness.mat --C /Users/bruehh01/Borderline_2/subjects/qdec/Untitled/contrasts/lh-X-PTSD-diagnostik-Intercept-thickness.mat

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