ttest

This program performs a 2 way T-test to determine the resolution of a reconstruction.

ttest ...

Description

This program's options parallel refine. 'ttest' options are a subset of refine's options. ttest is used to perform a fairly robust resolution determination on a reconstruction. It is run in the same directory as a completed refine command. Note that the refine command MUST terminate normally. Chances are good that if refine is interrupted in the middle of a run, ttest will not produce valid results. ttest splits each cls file into even and odd halves, then proceeds to build an independent model based on each half of the data. By calculating a Fourier shell correlation between the two resulting maps, a fairly robust resolution determination can be made. For a proper determination, the data should be split into 2, 4, 8, etc sets, then the resolution can be determined by interpolating to the entire data set. The estimate made by comparing 2 halves of the data is actually slightly underestimating the final resolution. Due to the rapid nonlinear falloff in signal to noise ratio at resolution limiting spatial frequencies, this underestimation should be relatively slight in most cases.


EMAN Manual page, generated Mon Jan 10 23:35:08 2000