:orphan: .. _ahelp_fdrval: ****** fdrval ****** .. contents:: :local: | .. code-block:: none Usage: fdrval [options] dset sub val [val ...] Reads FDR curve data from the header of dset for sub-brick #sub and computes the q-value when the sub-brick statistical threshold is set to val. OPTIONS ------- -pval = also output the p-value (on the same line, after q) -ponly = don't output q-values, just p-values -qonly = don't output p-values, just q-values [the default] -qinput = The 'val' inputs are taken to be q-values and then the *OR* outputs are the corresponding statistical thresholds. -inverse This is the inverse of the usual operation. * With this option, all 'val' inputs must be between 0 and 1 (exclusive), or bad things will happen and the program will send e-mail to your mother explaining how stupid you are. * You cannot use '-ponly' or '-pval' with this option. * For example, if you do fdrval dset+orig 1 1.2 and get a q-value of 0.234, then fdrval -qinput dset+orig 1 0.234 should return the value 1.2 -- the original threshold. (There may be a small discrepancy, due to the differences) (between forward interpolation and inverse interpolation.) * To set a (csh) variable to use in a script for thresholding via 3dcalc, you could do something like set tval = `fdrval -qinput dset+orig 1 0.05` 3dcalc -expr "step(a-$tval)" -a dset+orig'[1]' -prefix dmask NOTES ----- * Output for each 'val' is written to stdout. * If the q-value can't be computed, then 1.0 will be output. * If you input an absurdly high threshold, you will get the smallest q-value stored in the dataset header. (This is not necessarily exactly the smallest q-value that was computed originally, due to the way the FDR curves are calculated and interpolated.) * If you use '-qinput' and input a q-value that is too small for the FDR curve in the dataset header, you will get a threshold at or above the largest value in that sub-brick. * Sample usage: fdrval Fred_REML+orig 0 `count -scale 0.1 10 20` | 1dplot -stdin Uses the 'count' program to input a sequence of values, and then pipes into the 1dplot program to make a graph of F vs. q. * See the link below for information on how AFNI computes FDR curves: https://afni.nimh.nih.gov/pub/dist/doc/misc/FDR/FDR_Jan2008.pdf * Also see the output of '3dFDR -help' -- A quick hack by RWCox -- 15 Oct 2008 -- PG Wodehouse's birthday! -- Quick re-hack to add '-qinput' option -- 20 Dec 2011 -- RWCox -- Re-re-hack to make super-small '-qinput' values work right -- 14 Mar 2014 ++ Compile date = Oct 13 2022 {AFNI_22.3.03:linux_ubuntu_16_64}