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Dear all,

this error seems to be gdfCheckNPerClass in utils/fsgdf.cpp. Using "doss" or "DOSS" as a tag in the FSGD file doesn't help either, strangely. Could it be that it should be strcasecmp() instead of strcmp() in line 1046 of fsgdf.cpp?

Cheers, Cornelius

Date: Tue, 29 Jun 2021 15:19:20 +0000 From: "Dr. Cornelius Kronlage" Cornelius.Kronlage@med.uni-tuebingen.de Subject: [Freesurfer] mri_glmfit DOSS To: "'freesurfer@nmr.mgh.harvard.edu'" freesurfer@nmr.mgh.harvard.edu Message-ID: 2a173629cd4540769ec6a07d892ca618@med.uni-tuebingen.de Content-Type: text/plain; charset="us-ascii"

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Dear freesurfers,

for a morphometry study, I am comparing a single subject at a time to a group of controls. I would like to include age, gender (as a continuous variable for the sake of simplicity) and eTIV as "nuisance" regressors in the GLM. The FSGD looks like this:

GroupDescriptorFile 1 Title SUBJECT1_vs_allControls Class Test Class Controls Variables Age Gender eTIV Input SUBJECT1 Test 50 1 1497422.2500 Input SUBJECT2 Controls 30 0 1709039.536815 Input SUBJECT3 Controls 29 0 1423097.816203 Input SUBJECT4 Controls 31 1 1524690.026713 ...

When I try to run mri_glmfit I get the following error even though I specify DOSS:

$ mri_glmfit --fsgd SUBJECT1_vs_allControls.fsgd doss [...] gdfRead(): reading SUBJECT1_vs_allControls.fsgd WARNING: variable 1 is "Gender" which is often a discrete factor The proper way to handle discrete factors is to create classes. See https://secure-web.cisco.com/10ThHTirv10OEqbkasMHR-FObJ8JCIIzwnlckPdClcabJkN... INFO: DeMeanFlag keyword not found, DeMeaning will NOT be done. Continuous Variable Means (all subjects) 0 Age 28.6875 6.36611 1 Gender 0.46875 0.499022 2 eTIV 1.51444e+06 125811 Class Size and Means of each Continuous Variable 1 Test 1 50.0000 1.0000 1497422.2500 2 Controls 31 28.0000 0.4516 1514993.8589 ERROR: Class Test has 1 members. With 3 variables and using DODS, you need at least 4 members How do I get mri_glmfit to use DOSS, or do I have to specify the design matrix by hand in this case?

Thank you! Best wishes Cornelius