sorry, I mean to do it for both the FSGD file and the matlab script. I just tried it with your data and it works. doug
soft.join Huang wrote: > Hi, doug. > > Thanks for your suggestion, but it does not seem to work. > After having divided the ICV by 1e6, I reculated the betas, and got > the similar results as before in Matlab, just the beta4 -- > correspondent to ICV -- multiplied a 10^6. > And then I computed the rank of matrix X that the value is 4, > indicating that each 2 variables in design matrix do not highly > correlated. > Also I have finished an regress analysis including one class variable > and one continuous variable using mri_glmfit, got the same result in > Matlab. > A wired situation... > Is it any additional constrains in mri_glmfit when doing regression > analysis? > > Lijie Huang > > > On Mon, May 2, 2011 at 9:09 PM, Douglas N Greve > <gr...@nmr.mgh.harvard.edu <mailto:gr...@nmr.mgh.harvard.edu>> wrote: > > I think the problem may be that your data are "badly scaled" > meaning that one column is much greater than another column. Try > dividing the ICV by 1e6 and see if you get more similar results. > > doug > > soft.join Huang wrote: > > Doug, > Thanks for your reply. > I recalculated the beta value and got the same results as the > Matlab does, but be different from the mri_glmfit's. I can not > figure out where the problem is. > Details following: > I use the command > mri_glmfit --table lh.volume.txt --fsgd > volume.gender.fsgd doss --C gender.diff.mtx --glmdir lh.vol.glmdir > to finish regression analysis. and got the beta value ( > beta1 = 1.9781e+03, beta2 = 2.0639e+03, beta3 = 110.9220, > beta4 = 5.1964e-04 ) from beta.mgh file. > Using X.mat file and the same dependent variable Y.mat as > mri_glmfit's, I got totally different results in Matlab( beta1 > = 5.19e+02, beta2 = 4.44e+02, beta3 = 90.32, beta4 = 0.0015 ). > I don't know how it happened... > Hope for your reply. > The data I used are all in the attachment. > Best Regrads, > Lijie Huang > On Fri, Apr 29, 2011 at 9:45 PM, <gr...@nmr.mgh.harvard.edu > <mailto:gr...@nmr.mgh.harvard.edu> > <mailto:gr...@nmr.mgh.harvard.edu > <mailto:gr...@nmr.mgh.harvard.edu>>> wrote: > > Lijie, > > I don't know what the matlab regress() function does. > mri_glmfit > is just > solving the GLM equation, which you can do easily in matlab: > > beta = inv(X'*X)*X'*y; > > try that and see if you get the same as mri_glmfit. > > doug > > > > Hi all, > > > > I'm working on a group analysis using mri_glmfit. > > In analysis directory, I got a X.mat file which > containing the > matrix X ( > > size 50x4 ) used to regress analysis, also the beta value > from > beta.mgh > > file. > > Strangely, I loaded the X.mat in Matlab and recalculated the > beta using > > function regress in matlab, but got a different result > from that of > > mri_glmfit. > > I don't know where the problem is, is there any difference in > algorithm > > between mri_glmfit and matlab function regress( > regress(Y,X) )? > or I made > > some mistakes during the procedure. > > The X.mat file and the dependent variable Y.mat are in the > attachment. > > > > Thanks in advance > > > > Lijie Huang > > _______________________________________________ > > Freesurfer mailing list > > Freesurfer@nmr.mgh.harvard.edu > <mailto:Freesurfer@nmr.mgh.harvard.edu> > <mailto:Freesurfer@nmr.mgh.harvard.edu > <mailto:Freesurfer@nmr.mgh.harvard.edu>> > > > https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer > > > > The information in this e-mail is intended only for the > person to > whom it is > addressed. If you believe this e-mail was sent to you in > error and > the e-mail > contains patient information, please contact the Partners > Compliance HelpLine at > http://www.partners.org/complianceline . If the e-mail was > sent to > you in error > but does not contain patient information, please contact the > sender and properly > dispose of the e-mail. > > > > -- > Douglas N. Greve, Ph.D. > MGH-NMR Center > > gr...@nmr.mgh.harvard.edu <mailto:gr...@nmr.mgh.harvard.edu> > Phone Number: 617-724-2358 Fax: 617-726-7422 > > Bugs: surfer.nmr.mgh.harvard.edu/fswiki/BugReporting > <http://surfer.nmr.mgh.harvard.edu/fswiki/BugReporting> > FileDrop: www.nmr.mgh.harvard.edu/facility/filedrop/index.html > <http://www.nmr.mgh.harvard.edu/facility/filedrop/index.html> > > -- Douglas N. Greve, Ph.D. MGH-NMR Center gr...@nmr.mgh.harvard.edu Phone Number: 617-724-2358 Fax: 617-726-7422 Bugs: surfer.nmr.mgh.harvard.edu/fswiki/BugReporting FileDrop: www.nmr.mgh.harvard.edu/facility/filedrop/index.html _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
