The model scale searched b_sol only over 10-80 A^2. That is the range
Fokine & Urzhumtsev report for models at ordinary B, but on low-resolution
entries whose deposited B is 200-400 A^2 the fit sat on the 80 A^2 ceiling
(and k_sol on its 0.1 floor): a solvent edge far sharper than the atoms it
lies against, reaching too deep in resolution. R-free came out 0.05-0.10
above REFMAC (0 cycles) and phenix.model_vs_data on the same MTZ, model
and flags.
The ceiling is now max(80, 2 x the model's mean atomic B) (SolventBMax),
for the reported fit and for the rigid-body placement's per-zone solvent
(CPU, GPU and the host fallback alike). The grid keeps eight b_sol values
across a wider box, so it costs no more points; the default box, and so
every model with mean B <= 40 A^2, is bit-identical to before.
Measured (10 open-arm sets with --model, GPU build, vs the same base):
high-B set, 7.0 A: R-free 0.462 -> 0.364, b_sol 80 -> 379 (REFMAC 0.366,
REFMAC's own b_sol ~371; model_vs_data 0.291);
the rigid-body step now commits
high-B set, 3.9 A: 0.410 -> 0.331, b_sol 80 -> 388, k_sol 0.10 -> 0.225
(REFMAC 0.328, model_vs_data 0.314); null 10.1 -> 14.2 sigma
B~200 set, 3.2 A: 0.408 -> 0.402, b_sol 80 -> 120; enantiomorph label
decision unchanged (27.2 -> 25.8 sigma)
7 other sets (mean B 16-57): bit-identical R, k_sol, b_sol, placement.
p.hkl md5 and the MTZ reflection data are identical to the base on all 10.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
leonarski_fandClaude Opus 5.5
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