Ziad,

Having more knots in your TENT(b,c,n) than there are TRs in its duration does in fact kill 3dDeconvolve IF all the stimuli fall on integral multiples of TR, because you are using n regressors to model a space of spanned by floor((c-b)/TR)+1 translates of your stim file. A demonstration is appended-- note the warning about the inter-knot timing with TENT. I also tried this with '1D: 0 15.5 30', which worked with -polort -1 but failed without.

Isaac Schwabacher

[schwabacher@cayenne data]$ 3dDeconvolve -nodata 20 2 -polort -1 -num_stimts 1 -stim_times 1 '1D: 0 10 30' 'TENT(0,14,9)' -xjpeg temp.png
*+ WARNING: no -stim_label given for stim #1 ==> label = 'Stim#1'
++ 3dDeconvolve: AFNI version=AFNI_2011_12_21_1014 (Mar 19 2012) [64-bit]
++ Authored by: B. Douglas Ward, et al.
++ using TR=2 seconds for -stim_times and -nodata
++ using NT=20 time points for -nodata
++ -stim_times using TR=2 s for stimulus timing conversion
++ -stim_times using TR=2 s for any -iresp output datasets
++ [you can alter the -iresp TR via the -TR_times option]
++ ** -stim_times NOTE ** guessing GLOBAL times if 1 time per line; LOCAL otherwise
*+ WARNING: -stim_times 1 .. TENT(0,14,9) has inter-knot TR=1.75 but -iresp output TR=2
++ ** GUESSED ** -stim_times 1 using LOCAL times
++ Number of time points: 20 (no censoring)
+ Number of parameters: 9 [0 baseline ; 9 signal]
++ Wrote matrix image to file temp.png
++ Wrote matrix values to file nodata.xmat.1D
++ ----- Signal+Baseline matrix condition [X] (20x9): 1.46968 ++ VERY GOOD ++
*+ WARNING: !! in Signal+Baseline matrix:
* Largest singular value=1.44042
* 1 singular value is less than cutoff=1.44042e-07
* Implies strong collinearity in the matrix columns!
++ Signal+Baseline matrix singular values:
0 0.666875 0.760803 0.800885 0.911369
1.1037 1.24641 1.28761 1.44042
++ ----- Signal-only matrix condition [X] (20x9): 1.46968 ++ VERY GOOD ++
*+ WARNING: !! in Signal-only matrix:
* Largest singular value=1.44042
* 1 singular value is less than cutoff=1.44042e-07
* Implies strong collinearity in the matrix columns!
++ Signal-only matrix singular values:
0 0.666875 0.760803 0.800885 0.911369
1.1037 1.24641 1.28761 1.44042
++ Wrote matrix values to file nodata_XtXinv.xmat.1D
*+ WARNING: +++++ !! Matrix inverse average error = 0.0568239 ** BEWARE **
++ Matrix setup time = 0.35 s

Stimulus: Stim#1
h[ 0] norm. std. dev. = 0.6325
h[ 1] norm. std. dev. = 0.7518
h[ 2] norm. std. dev. = 0.8959
h[ 3] norm. std. dev. = 0.8127
h[ 4] norm. std. dev. = 0.7021
h[ 5] norm. std. dev. = 0.8563
h[ 6] norm. std. dev. = 1.0983
h[ 7] norm. std. dev. = 0.9214
h[ 8] norm. std. dev. = 0.7746