Changes between Version 12 and Version 13 of requests


Ignore:
Timestamp:
Apr 13, 2009, 1:04:19 PM (17 years ago)
Author:
goddard
Comment:

--

Legend:

Unmodified
Added
Removed
Modified

  • requests

    v12 v13  
    1010Currently they include only those collected by Tom Goddard (focus on
    1111density maps, molecular assemblies, electron microscopy).
     12</p>
     13
     14<p>
     15175.
     16<b>FFT better memory efficiency.</b><br>
     17Benoit Zuber<br>
     18April 13, 2009<br>
     19An FFT of a 32-bit float map takes 8 times the memory of the original map
     20because it produces a complex double precision results (4x) then the absolute
     21value (2x), then cast to single-precision (1x), then recentering (1x).  A variety
     22of optimizations could reduce this although using a different FFT package like
     23fftw would be needed to use single precision since our current numpy fft only
     24supports double precision.
    1225</p>
    1326