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sulantha2006 / VoxelStats

A MATLAB package for multi-modal voxel-wise brain image analysis
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Exception occured - values for the voxel forced 0. #8

Open guangyuanzou opened 3 years ago

guangyuanzou commented 3 years ago

Hello, Sulantha

I want to analyse the change of A between two conditions (m vs n), using B as voxel-wise covariates. The images were my setup and csv file. I got an error: Exception occured - values for the voxel forced 0. Error Fixed Effects design matrix X must be of full column rank

Could you give me some suggestions? Thanks.

csv setup

sulantha2006 commented 3 years ago

It can happen for some voxels, especially for background voxels. If that happens for all voxels, then there is something wrong with your model. It may be that you dont degrees of freedom for the model to converge. Can you do a single voxel test. ? (Get values from a single known voxel, and run the analysis). If it generates a correct result, see the same voxel result in VS output. )

On Mon, Apr 19, 2021 at 6:26 AM zou13 @.***> wrote:

Hello, Sulantha

I want to analyse the change of A between two conditions (m vs n), using B as voxel-wise covariates. The images were my setup and csv file. I got an error: Exception occured - values for the voxel forced 0. Error Fixed Effects design matrix X must be of full column rank

Could you give me some suggestions? Thanks.

[image: csv] https://user-images.githubusercontent.com/69659877/115241170-187af180-a153-11eb-94f7-40f79f9dd085.png [image: setup] https://user-images.githubusercontent.com/69659877/115241175-19ac1e80-a153-11eb-937f-4c1d0d862c3d.png

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guangyuanzou commented 3 years ago

It can happen for some voxels, especially for background voxels. If that happens for all voxels, then there is something wrong with your model. It may be that you dont degrees of freedom for the model to converge. Can you do a single voxel test. ? (Get values from a single known voxel, and run the analysis). If it generates a correct result, see the same voxel result in VS output. ) … On Mon, Apr 19, 2021 at 6:26 AM zou13 @.**> wrote: Hello, Sulantha I want to analyse the change of A between two conditions (m vs n), using B as voxel-wise covariates. The images were my setup and csv file. I got an error: Exception occured - values for the voxel forced 0. Error Fixed Effects design matrix X must be of full column rank* Could you give me some suggestions? Thanks. [image: csv] https://user-images.githubusercontent.com/69659877/115241170-187af180-a153-11eb-94f7-40f79f9dd085.png [image: setup] https://user-images.githubusercontent.com/69659877/115241175-19ac1e80-a153-11eb-937f-4c1d0d862c3d.png — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#8>, or unsubscribe https://github.com/notifications/unsubscribe-auth/AAHZL5Z33ZGXVROHLHZ7SIDTJQVRPANCNFSM43F2STCQ .

You are right. The results are reasonable. Thank you.