Hi Rick,

Thanks for your insight into why this analysis may be taking so long! To clarify, the analyses I run do work in the end, they just take some time. I also discovered that the computer was going to sleep after some time left unattended, so the multi-day analysis I mentioned earlier was a false alarm. After adjusting the system settings to avoid sleep mode, I was able to do an analysis in 1-3 hours. This is obviously still longer than the ~5-10 minutes you seem to be getting, but at least the analyses are working.

As I understand it, the default number of simulations is in 3dttest++ is 10,000. I was able to run an analysis with this default overnight and it seemed to take about 2 hours and converged just fine in the end. The output of 3dttest++ does mention that it requires something like 52 GB of RAM for the analysis, and that my system only has around 8 GB (see the code pasted in my other reply to ptaylor). As for using a better machine, there are some logistical / ethical rules on our end in terms of data privacy, so we hope to keep the data on this one machine. For now then, I'll ask our IT department about some RAM upgrades to this iMac and otherwise I will keep chugging along with an analysis finished every 2-3 hours. I don't have that many contrasts, so it shouldn't take more than a few days.

- Brady