leonarski_fandClaude Opus 5
3d7891c347
The resolution cutoff, the shell table and the overall CC1/2 counted every unique reflection equally. The merge itself is inverse-variance weighted, so an observation from a frame the crystal barely diffracted on enters it at 1/G^2 of a good one - honestly, with its sigma - but a reflection measured only on such frames is scaled-up noise that then counts as much as a well-measured pair in every Pearson CC1/2 read off the merge. On a sweep where half the frames are weak the curve collapses at every resolution: the cut lands at 3.7 A on a P1 crystal whose good frames reach 1.5 A, and the UNUSABLE verdict fires (CC1/2 0.40 beside I/sigma 10). Each merged reflection now carries cc_weight: the precision its half-sets would have had with every observation at the run's typical frame scale, over the precision they have. G_ref = sum G^3 / sum G^2 over the usable observations is the precision-weighted typical scale, which the dead frames cannot drag down however many there are; the factor per observation is max(1, (G_ref/G)^2), with G the frame's total scale (partial scale, flux and the fulls' own G) taken before the correction surfaces and before collapsed frames are dropped, so nothing intensity- or resolution-dependent enters it. On a sweep without a weak stretch every weight is 1 and the CC1/2 is the plain Pearson it was. The cutoff fit, the shell table and the overall CC1/2 (and so the UNUSABLE verdict and the report's shell checks) all read the same weighted statistic. The two extra per-group sums are accumulated on both merge paths, the host loop and MergeAccumKernel, from one per-frame factor array; a host recompute of the device sums agrees to 1e-15 relative on every merge after the corrected corr is uploaded, and a host-merge run gives the same cut, space group, CC1/2 and ISa on five sets. Weighting by the half-set error variance alone (1/(v0+v1)) is not this: v grows with the intensity, so it weights the weak end of the intensity distribution and biases homogeneous data coarser. Measured (written resolution, together with the weighted outlier median): a P1 sweep with a long weak stretch 3.73 -> 1.40 A against a 1.63 A XDS reference, UNUSABLE withdrawn (overall CC1/2 0.40 -> 0.97); a second 3.61 -> 3.00 A; one with most of the sweep out of beam 7.35 -> 5.20 A. Lysozyme, thaumatin and two insulin sets unchanged to 0.01 A (one lysozyme sweep with a weak wedge 1.13 -> 1.16 A, from the median), same space groups throughout. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
21 lines
568 B
C++
21 lines
568 B
C++
// SPDX-FileCopyrightText: 2024 Filip Leonarski, Paul Scherrer Institute <filip.leonarski@psi.ch>
|
|
// SPDX-License-Identifier: GPL-3.0-only
|
|
|
|
#pragma once
|
|
|
|
class CorrelationCoefficient {
|
|
double sum_x = 0.0;
|
|
double sum_y = 0.0;
|
|
double sum_x2 = 0.0;
|
|
double sum_y2 = 0.0;
|
|
double sum_xy = 0.0;
|
|
double sum_w = 0.0;
|
|
int n_cc = 0;
|
|
public:
|
|
void Add(double x, double y) { Add(x, y, 1.0); }
|
|
// Weighted pair: a plain Pearson when every weight is the same.
|
|
void Add(double x, double y, double w);
|
|
[[nodiscard]] double GetCC() const;
|
|
};
|
|
|