Usage: 3ddot [options] dset1 [dset2 dset3 ...] Output = correlation coefficient between sub-brick pairs
All datasets on the command line will get catenated at loading time and should all be on the same grid. - you can use sub-brick selectors on the dsets - the result is a number printed to stdout
Options:
- -mask mset Means to use the dataset ‘mset’ as a mask:
- Only voxels with nonzero values in ‘mset’ will be averaged from ‘dataset’. Note that the mask dataset and the input dataset must have the same number of voxels.
- -mrange a b Means to further restrict the voxels from
- ‘mset’ so that only those mask values between ‘a’ and ‘b’ (inclusive) will be used. If this option is not given, all nonzero values from ‘mset’ are used. Note that if a voxel is zero in ‘mset’, then it won’t be included, even if a < 0 < b.
- -demean Means to remove the mean from each volume
- prior to computing the correlation.
-docor Return the correlation coefficient (default).
-dodot Return the dot product (unscaled).
- -docoef Return the least square fit coefficients
- {a,b} so that dset2 is approximately a + b*dset1
- -dosums Return the 6 numbers xbar=<x> ybar=<y>
- <(x-xbar)^2> <(y-ybar)^2> <(x-xbar)(y-ybar)> and the correlation coefficient.
-doeta2 Return eta-squared (Cohen, NeuroImage 2008).
-dodice Return the Dice coefficient (the Sorensen-Dice index).
- -show_labels Print sub-brick labels to help identify what
- is being correlated. This option is useful when you have more than 2 sub-bricks at input.
-upper Compute upper triangular matrix
- -full Compute the whole matrix. A waste of time, but handy
- for parsing.
- -1D Comment headings in order to read in 1D format.
- This is only useful with -full.
- -NIML Write output in NIML 1D format. Nicer for plotting.
-full and -show_labels are automatically turned on with -NIML. For example:
- 3ddot -NIML anat.001.sc7z.sigset+orig”[0,1,2,3,4]”
- > corrmat.1D
1dRplot corrmat.1D
- or
- 1dRplot -save somecorr.jpg -i corrmat.1D
Note: This program is not efficient when more than two subbricks are input.
This program accepts datasets that are modified on input according to the following schemes:
‘r1+orig[3..5]’ {sub-brick selector} ‘r1+orig<100..200>’ {sub-range selector} ‘r1+orig[3..5]<100..200>’ {both selectors} ‘3dcalc( -a r1+orig -b r2+orig -expr 0.5*(a+b) )’ {calculation}
For the gruesome details, see the output of ‘afni -help’.
++ Compile date = Dec 16 2015