refined_shared() recomputed R-free as sum|F - FC_ALL_LS| / sum F from REFMAC's output MTZ. That
MTZ's F is not the input F: REFMAC writes it with its overall anisotropic scale applied. On
strongly anisotropic data the scale multiplies the noise of the weak direction, and the recomputed
R comes out far above REFMAC's own R-free over the very same reflections.
9RCS (deltaB ~250 A^2, deposit STARANISO-corrected): the recomputed shared-set R-free was 0.503
against REFMAC's own 0.368 on the same 378 free reflections (deposit 0.366/0.365), which is the
whole of the +0.137 the open arm reported for this set. Across the 152 untwinned rc173 sets the
two agree to a median 0.0001 and to within 0.03 everywhere else.
Both refinements' free sets are the shared set by construction, so REFMAC's own R-free is the
shared-set number already, as the twin branch used it.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01K5K8jvPPbmCrbqnWkddTuB
leonarski_fandClaude Opus 5.5
1bab3e57b9