Hi Phillip, sorry, that was an oversight. Replace - real_map = fft_map.real_map() + real_map = fft_map.real_map_unpadded() and it should print identical values.
Is there any reason for the different sizes of the tag_array and the real_map? real_map.last() and tag_array.last() show different results.
That was exactly the problem. The real_map is padded because of FFT requirements. The tag_array is not. .real_map_unpadded() will make a copy. There will be another copy to restore the padding in .structure_factors_from_map() call. The two copies can be avoided in C++, but it is to cumbersome from Python. Ralf ____________________________________________________________________________________ Pinpoint customers who are looking for what you sell. http://searchmarketing.yahoo.com/