Two measurements, neither of which changes what we write.
phenix's "Multiple equally suitable arrays" is a tie between the two
INTENSITY arrays, IMEAN and I(+)/I(-); iotbx scores F and F(+)/F(-) below
them, so writing amplitudes as well is not what causes it. ctruncate's own
output ties in the same place, so this is what phenix does with a CCP4 merged
file rather than something rugnux does to a user. Column order, dataset and
project names, and dropping the amplitudes all leave the tie exactly where it
was; only removing one of the two intensity arrays clears it, and removing the
Bijvoet columns would take the SHELX route with it. So the file stays as it is
and the page now carries the label line per program, both formats, including
the quoting the anomalous one needs. A program that asks iotbx for anomalous
data by preference - hyss, find_peaks_holes, molprobity, the autosol import -
needs nothing at all, which is now said as well.
The page also said the MTZ form of that message names no choices. It names
both, exactly as the mmCIF form does; corrected.
DANO/SIGDANO stay out. Against a ctruncate file, DANO is F(+)-F(-) and SIGDANO
is the quadrature sum of the two sigmas, bit-identical on every reflection, so
the pair is a restatement of columns we already write - and the quadrature sum
is the convention whether or not the mates share a scale model. Every consumer
in the documented routes takes the Bijvoet columns directly, CCP4's own bp3 and
afro ask for them in preference to F/DANO, and adding the pair costs 12.5% of
the merged file while changing nothing phenix or Phaser sees. fft's anomalous
Fourier is the one caller with no other spelling; the ctruncate command that
makes it is now on the page.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EFEJG6WBQv8th4UJFNe53N
leonarski_fandClaude Opus 5
0eb9fb8a8b
