rc180
2
Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
 leonarski_f
|
bda90dbdd5 |
Refinement: B restraints in proportion to B (Kullback-Leibler form) with contacts, an own ADP weight, overall B into the atoms
- B similarity: E = (B_i - B_j)^2 / (kappa^2 B_i B_j), the symmetric Kullback-Leibler divergence of two isotropic Gaussians (Murshudov et al. 2011), so sigma = kappa sqrt(B_i B_j) instead of a fixed 1.5-4.5 A^2. kappa 0.1 / 0.133 / 0.2 / 0.3 for main-chain bonded / angle-related and side-chain pairs (REFMAC's logs list sigma ~0.1 B for main-chain bonded pairs at B 11-140; the ratios are those of the old sigmas, which these equal at B = 15). New class: atoms within 4 A that no bond or angle relates, waters and symmetry mates included, kappa 0.5 (BuildBContacts, sharing the neighbour search with BuildRepulsions). CPU and GPU. - The B factors' X-ray weight is balanced on its own (BalancedADPWeight: B-restraint over X-ray B-gradient on the model with B shaken by 20%) instead of being a multiple of the positional weight; the ladder tries B held and refined at that weight, the trajectory's B steps divide and multiply it by four, positional steps and the final ladder leave it. - Before each B-refining macro-cycle the overall isotropic B of the scale moves into the atoms and the solvent's B (F_model unchanged), so the two do not drift against each other. Tried and not kept: xyz and B as one L-BFGS vector (the B block scaled by its curvature, the positions by the median X-ray curvature): no better than alternation with a memory per block on 12 starts (mean R-free 0.265 vs 0.262), worse on 7arr/7d98; a refit before each B step: no gain for +20-40% time. Refinement battery MD starts, median R-free by the REFMAC 0-cycle scorer, previous commit -> this (REFMAC to convergence): 5f6m x8 0.167 -> 0.167 (0.168), 8dqb x8 0.291 -> 0.294 (0.284), 7arr x4 0.270 -> 0.278 (0.311), 11if x4 0.245 -> 0.244 (0.251), 5reo x4 0.312 -> 0.258 (0.261: the ladder no longer keeps B held where B is the model's largest error), 7d98 x4 0.342 -> 0.335 (0.361). Deposited models: unchanged (B stays held there). Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_015CeEGgpKdfkCTJb3YNMJcu (cherry picked from commit ed292f35b482b696d81f71f1d97e0016ca05b144) |
||
|
leonarski_f
|
b4b68d368f |
Restrained refinement on the GPU: ML amplitude target, FFT gradient, dictionary restraints, R1 + R2 driver, blobs
RefineModel (Refinement.h) refines a placed model against the merge, reading and writing nothing: - placement stage (R1): every chain of 50+ atoms as a rigid body at once (L-BFGS on six parameters per chain, their gradient from the per-atom one through Ceres jets), then one B shift per residue; - restrained stage (R2): positions and isotropic B of every atom of a residue the embedded dictionary describes, the rest held fixed but kept in Fcalc and the mask; riding hydrogens added by gemmi's topology, moved with their parents, re-placed every macro-cycle. Macro-cycles refit the mask, the scale and bulk solvent (FitModelScale / ModelScaleGPUPool) and the likelihood's D and beta (ML on the free set in resolution bins), rebuild the repulsion pairs (symmetry mates included), then L-BFGS on positions and, where chosen, on B. - weights: a ladder of full refinements at multiples of the gradient-balanced X-ray weight, chosen by R-free within bond/angle bounds (ties to the tighter geometry), then the B refinement tried at its own weights and kept only where it beats B held by more than the tie. The target and its gradient (RefinementXray, RefinementGPU): the Rice/centric amplitude likelihood (RefinementMath.h, shared host/device code), the gradient by Agarwal's FFT method - the adjoint of the reciprocal-space symmetry composition into a half-l (CPU) or half-u (cuFFT) spectrum, one inverse real transform, then each atom's density derivatives (xyz and B) summed over its box. On the GPU everything per evaluation stays on the device: ModelDensityGPU's gather, r2c, a fused compose + likelihood kernel, a CSR gather for the adjoint (no atomics), c2r, one warp per atom for the gradient; the restraints are one kernel per restraint plus a per-atom gather of gradient slots; cub reductions. Deterministic. Restraints (RefinementRestraints): bonds, angles, torsions (with esd, no phi/psi, no alternative sugar puckers), chiral volumes, least-squares planes from gemmi's Topo; repulsions beyond 1-4 (vdW radii from the dictionary's energy library, 2.6 A for H-bond pairs, 1.9 A metal-N/O/S); B similarity of bonded and angle-related atoms. DensityBlobs (D1): gemmi's flood-fill blobs of mFo-DFc above 3 sigma peaking above 4 sigma, placed beside the model and labelled WATER / ION / LIGAND / MODEL_ERROR by distance, contacts, volume and the anomalous map. tools/rugnux_refine_test refines a model against a finished run's p.mtz (developer utility, not installed). Tests: likelihood derivative, the embedded library, restraint values on ideal residues and every restraint kind's gradient against finite differences (CPU, and the GPU against the CPU), the X-ray gradient against finite differences in P1, P212121, C2 and P6122 (CPU and GPU), and a synthetic refinement that recovers a shaken model. Credits in docs/ACKNOWLEDGEMENT.md and at the algorithms. Measured on the open arm's battery outputs against REFMAC 5.8, 10 cycles, same p.mtz, free set and start model (R-free): 5reo 0.2228 vs 0.2236, 8dyz 0.1733 vs 0.1651, 9chw 0.1995 vs 0.1969 (CPU engine). Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_015CeEGgpKdfkCTJb3YNMJcu (cherry picked from commit 8efe6f2322b3bfdae580bb34f256e67730dfc3c2) |