[phenixbb] question about FFT map coefficients

Nathaniel Echols nechols at lbl.gov
Fri Mar 29 10:41:39 PDT 2013

On Fri, Mar 29, 2013 at 10:31 AM, Michael Thompson <miket at chem.ucla.edu> wrote:
> The FFT didn't work out, but I'm not sure if it's due to negative Fs. When I set up the FFT map coefficients utility with my mtz file, after picking my input I get a warning that "The reflections file does not appear to contain any suitable map coefficients." Then if I try to run it anyway I get the error message "There are no map coefficients in this MTZ file."
> An mtz dump confirms that I have columns FP and SIGFP. Additional info: these Fs were generated using a python script that I wrote, and there are not meaningful values for SIGFP. My script simply wrote out 0.000 to the SIGFP column for each reflection essentially as a place holder. I thought that maybe 0 was not a valid entry for SIGFP so I changed it to 0.001 so there would be some value there, but I get all the same errors. Could this be the problem?

SIGFP doesn't matter - only amplitudes, phases, and optionally FOM are
used in the calculation.  It sounds like your MTZ file doesn't contain
recognizable phases - can you send me the output of "phenix.mtz.dump
data.mtz"?  (I only really need the part that lists columns.)


More information about the phenixbb mailing list