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Jungfraujoch/image_analysis/scale_merge/ScaleOnTheFly.cpp
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leonarski_fandClaude Fable 5 1ca5a69054 ScaleOnTheFly: solve the per-image scale by IRLS instead of Ceres
In the default rotation (rot3d) path only G is refined - B is fixed, mosaicity
is pinned and the wedge is not refined - so the predicted intensity G*coeff is
linear in G and the robust (Cauchy) per-image scale is a 1-D M-estimate. Solve
it directly by iteratively reweighted least squares (a few closed-form weighted
ratios) instead of building a Ceres problem per image. Ceres is kept for the
cases that are genuinely nonlinear: refining the B-factor or the rotation wedge.

Same Cauchy objective as the Ceres path, but ~4x faster at scaling and ~30%
faster overall on the /data/rotation_test battery, with space group, cell, ISa,
completeness and CC1/2 matching across all 18 crystals (the two that look
different, EP_cs_01-17 and EcwtAL500, are run-to-run unstable for both solvers).
lyso_ref scaling 25.2->4.3s, cytC_2 15.2->2.6s, battery total 468->316s.

Also drop the per-image G/B regularizers (gated by GetScalingRegularize, which
nothing enables) and the now-unused RegularizationResidual.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-02 13:55:04 +02:00

466 lines
17 KiB
C++

// SPDX-FileCopyrightText: 2025 Filip Leonarski, Paul Scherrer Institute <filip.leonarski@psi.ch>
// SPDX-License-Identifier: GPL-3.0-only
#include "ScaleOnTheFly.h"
#include <algorithm>
#include <cmath>
#include <future>
#include <vector>
#include <ceres/ceres.h>
#include <ceres/rotation.h>
namespace {
// Robust loss scale (in sigma units) for the per-image scale fit: a few outlier reflections
// (zingers, overlaps, a mis-predicted spot) must not drag a frame's G/B into a bad optimum -
// that is the stochastic per-frame mis-scaling that elevates R-meas and collapses CC1/2 at low
// symmetry. Cauchy down-weights residuals beyond ~this many sigma without a hard cut.
constexpr double SCALE_ROBUST_K = 3.0;
double SafeInv(double x, double fallback) {
if (!std::isfinite(x) || x == 0.0)
return fallback;
return 1.0 / x;
}
float RotationPartiality( double delta_phi_deg,
double zeta,
double mosaicity_deg,
double wedge_deg) {
const double half_wedge = wedge_deg / 2.0;
const double c1 = zeta / std::sqrt(2.0);
const double arg_plus = (delta_phi_deg + half_wedge) * c1 / mosaicity_deg;
const double arg_minus = (delta_phi_deg - half_wedge) * c1 / mosaicity_deg;
return static_cast<float>((std::erf(arg_plus) - std::erf(arg_minus)) / 2.0);
}
// One reflection reduced to the 1-D scale fit: predicted intensity is G * coeff (coeff is constant
// while B, mosaicity and wedge are fixed), measured is Iobs, weighted by 1/sigma.
struct ScaleObs {
double coeff;
double Iobs;
double weight;
};
// Robust per-image scale: minimise sum_i Cauchy_k( weight_i (G*coeff_i - Iobs_i) ) over G >= 0. The
// model is linear in G, so this M-estimate is a few reweighted-least-squares steps (each a closed-form
// weighted ratio) - the same objective the Ceres path solves, without a per-image problem/autodiff/
// trust-region. Seeded from the plain weighted-LS solution; Cauchy weight is 1/(1 + (res/k)^2).
double SolveScaleIRLS(const std::vector<ScaleObs> &obs, double robust_k) {
auto weighted_scale = [&obs](auto robust_weight) {
double num = 0.0, den = 0.0;
for (const auto &o: obs) {
const double rw = robust_weight(o);
const double w2 = o.weight * o.weight;
num += rw * w2 * o.coeff * o.Iobs;
den += rw * w2 * o.coeff * o.coeff;
}
return den > 0.0 ? num / den : NAN;
};
double G = weighted_scale([](const ScaleObs &) { return 1.0; });
if (!std::isfinite(G))
return 1.0;
G = std::max(0.0, G);
const double k2 = robust_k * robust_k;
for (int iter = 0; iter < 30; ++iter) {
const double G_prev = G;
const double G_next = weighted_scale([&](const ScaleObs &o) {
const double res = o.weight * (G * o.coeff - o.Iobs);
return 1.0 / (1.0 + res * res / k2);
});
if (!std::isfinite(G_next))
break;
G = std::max(0.0, G_next);
if (std::abs(G - G_prev) <= 1e-7 * std::max(G, 1.0))
break;
}
return G;
}
class ScalingResidual {
protected:
const double Iobs;
const double Itrue;
const double weight;
const double lp;
const double b_resolution_coeff;
ScalingResidual(const Reflection &r, double Itrue, double sigma)
: Iobs(r.I),
Itrue(Itrue),
weight(SafeInv(sigma, 1.0)),
lp(SafeInv(r.rlp, 1.0)),
b_resolution_coeff(-SafeInv(4.0 * r.d * r.d, 0.0)) {
}
};
struct ScalingRotationResidual : public ScalingResidual {
ScalingRotationResidual(const Reflection &r, double Itrue, double sigma)
: ScalingResidual(r, Itrue, sigma),
delta_phi_deg(r.delta_phi_deg),
c1(r.zeta / std::sqrt(2.0)) {
}
template<typename T>
bool operator()(const T *const G,
const T *const B,
const T *const mosaicity,
const T *const wedge,
T *residual) const {
if (mosaicity[0] < 1e-6)
return false;
const T half_wedge = wedge[0] / T(2.0);
const T arg_plus = (T(delta_phi_deg) + half_wedge) * T(c1) / mosaicity[0];
const T arg_minus = (T(delta_phi_deg) - half_wedge) * T(c1) / mosaicity[0];
const T partiality = (ceres::erf(arg_plus) - ceres::erf(arg_minus)) / T(2.0);
const T B_term = ceres::exp(B[0] * T(b_resolution_coeff));
residual[0] = (G[0] * partiality * B_term * T(lp) * T(Itrue) - T(Iobs)) * T(weight);
return true;
}
double delta_phi_deg;
double c1;
};
struct IntensityFixedResidual : public ScalingResidual {
IntensityFixedResidual(const Reflection &r, double Itrue, double sigma, double partiality)
: ScalingResidual(r, Itrue, sigma),
partiality(partiality) {
}
template<typename T>
bool operator()(const T *const G, const T *const B, T *residual) const {
const T B_term = ceres::exp(B[0] * T(b_resolution_coeff));
residual[0] = (G[0] * T(partiality) * B_term * T(lp) * Itrue - T(Iobs)) * T(weight);
return true;
}
double partiality;
};
struct RotationNormRegularizer {
explicit RotationNormRegularizer(double weight) : weight(weight) {}
template<typename T>
bool operator()(const T *const rot_aa, T *residual) const {
residual[0] = T(weight) * rot_aa[0];
residual[1] = T(weight) * rot_aa[1];
residual[2] = T(weight) * rot_aa[2];
return true;
}
const double weight;
};
}
ScaleOnTheFly::ScaleOnTheFly(const DiffractionExperiment &x, const std::vector<MergedReflection> &ref)
: sg(x.GetGemmiSpaceGroup()),
model(x.GetPartialityModel()),
s(x.GetScalingSettings()),
rot_wedge_deg(x.GetRotationWedgeForScaling()),
refine_rot_wedge(x.GetRefineRotationWedgeInScaling()),
hkl_key_generator(s.GetMergeFriedel(), x.GetSpaceGroupNumber().value_or(1)) {
for (const auto &r: ref) {
const auto key = hkl_key_generator(r);
reference_data[key] = r.I;
}
}
bool ScaleOnTheFly::Accept(const Reflection &r) const {
if (!AcceptReflection(r, s.GetHighResolutionLimit_A()))
return false;
switch (model) {
case PartialityModel::Rotation:
return std::isfinite(r.zeta) && r.zeta > 0.0f;
case PartialityModel::Fixed:
case PartialityModel::Unity:
return true;
}
return true;
}
std::pair<double, size_t> ScaleOnTheFly::CalculateGlobalCC(const std::vector<Reflection> &reflections) const {
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;
size_t n = 0;
for (const auto &r: reflections) {
if (!AcceptReflection(r, s.GetHighResolutionLimit_A()))
continue;
if (r.partiality < s.GetMinPartiality())
continue;
if (!std::isfinite(r.I) || !std::isfinite(r.image_scale_corr) || r.image_scale_corr <= 0.0f)
continue;
if (!std::isfinite(r.sigma) || r.sigma <= 0.0f)
continue;
const HKLKey key = hkl_key_generator(r);
const auto it = reference_data.find(key);
if (it == reference_data.end())
continue;
const double image_i = static_cast<double>(r.I) * static_cast<double>(r.image_scale_corr);
const double ref_i = it->second;
if (!std::isfinite(image_i) || !std::isfinite(ref_i))
continue;
sum_x += image_i;
sum_y += ref_i;
sum_x2 += image_i * image_i;
sum_y2 += ref_i * ref_i;
sum_xy += image_i * ref_i;
++n;
}
if (n < MIN_REFLECTIONS)
return {NAN, n};
const double nd = static_cast<double>(n);
const double cov = sum_xy - sum_x * sum_y / nd;
const double var_x = sum_x2 - sum_x * sum_x / nd;
const double var_y = sum_y2 - sum_y * sum_y / nd;
if (!(var_x > 0.0 && var_y > 0.0))
return {NAN, n};
return {cov / std::sqrt(var_x * var_y), n};
}
void ScaleOnTheFly::Scale(IntegrationOutcome &integration_outcome) const {
if (integration_outcome.reflections.empty())
return;
auto start = std::chrono::steady_clock::now();
ScaleOnTheFlyResult result{
.B = 0.0,
.G = 1.0,
.R = {0.005, 0.005}
};
if (model == PartialityModel::Rotation) {
if (integration_outcome.mosaicity_deg
&& std::isfinite(*integration_outcome.mosaicity_deg)
&& *integration_outcome.mosaicity_deg > 0.0)
result.mos = *integration_outcome.mosaicity_deg;
else
result.mos = s.GetDefaultMosaicity();
if (const auto forced = s.GetForcedMosaicity(); forced.has_value())
result.mos = *forced;
result.wedge = rot_wedge_deg.value_or(0.0);
} else {
result.mos = NAN;
result.wedge = NAN;
}
auto clear_scale = [&]() {
integration_outcome.image_scale_cc.reset();
integration_outcome.image_scale_cc_n.reset();
integration_outcome.image_scale_g.reset();
integration_outcome.image_scale_b_factor_Ang2.reset();
};
// With B, mosaicity and wedge all fixed the predicted intensity G * coeff is linear in G, so the
// robust per-image scale is a 1-D M-estimate solved directly (IRLS) instead of building a Ceres
// problem per image. Ceres is kept only for the cases that make it genuinely nonlinear: refining the
// B-factor (exp(-B/...)) or the rotation wedge (which moves the partiality).
const bool linear_in_g = !s.GetRefineB()
&& (model != PartialityModel::Rotation || !refine_rot_wedge);
if (linear_in_g) {
std::vector<ScaleObs> obs;
obs.reserve(integration_outcome.reflections.size());
for (const auto &r: integration_outcome.reflections) {
if (!Accept(r))
continue;
const auto it = reference_data.find(hkl_key_generator(r));
if (it == reference_data.end())
continue;
double partiality;
switch (model) {
case PartialityModel::Unity:
partiality = 1.0;
break;
case PartialityModel::Rotation:
partiality = RotationPartiality(r.delta_phi_deg, r.zeta, result.mos, result.wedge);
break;
default:
partiality = r.partiality;
break;
}
const double B_term = std::exp(result.B * -SafeInv(4.0 * r.d * r.d, 0.0));
const double coeff = partiality * B_term * SafeInv(r.rlp, 1.0) * it->second;
obs.push_back({coeff, static_cast<double>(r.I), SafeInv(r.sigma, 1.0)});
}
if (obs.size() < MIN_REFLECTIONS) {
clear_scale();
return;
}
result.G = SolveScaleIRLS(obs, SCALE_ROBUST_K);
} else {
ceres::Problem problem;
size_t n_reflections = 0;
for (const auto &r: integration_outcome.reflections) {
if (!Accept(r))
continue;
const HKLKey key = hkl_key_generator(r);
if (!reference_data.contains(key))
continue;
++n_reflections;
const double Itrue = reference_data.at(key);
const double sigma = r.sigma;
switch (model) {
case PartialityModel::Fixed: {
auto *cost = new ceres::AutoDiffCostFunction<IntensityFixedResidual, 1, 1, 1>(
new IntensityFixedResidual(r, Itrue, sigma, r.partiality));
problem.AddResidualBlock(cost, new ceres::CauchyLoss(SCALE_ROBUST_K), &result.G, &result.B);
}
break;
case PartialityModel::Unity: {
auto *cost = new ceres::AutoDiffCostFunction<IntensityFixedResidual, 1, 1, 1>(
new IntensityFixedResidual(r, Itrue, sigma, 1.0));
problem.AddResidualBlock(cost, new ceres::CauchyLoss(SCALE_ROBUST_K), &result.G, &result.B);
}
break;
case PartialityModel::Rotation: {
auto *cost = new ceres::AutoDiffCostFunction<ScalingRotationResidual, 1, 1, 1, 1, 1>(
new ScalingRotationResidual(r, Itrue, sigma));
problem.AddResidualBlock(cost, new ceres::CauchyLoss(SCALE_ROBUST_K), &result.G, &result.B,
&result.mos, &result.wedge);
}
break;
default:
throw JFJochException(JFJochExceptionCategory::InputParameterInvalid,
"Not supported partiality model");
}
}
if (n_reflections < MIN_REFLECTIONS) {
clear_scale();
return;
}
problem.SetParameterLowerBound(&result.G, 0, 0.0);
if (s.GetRefineB()) {
problem.SetParameterLowerBound(&result.B, 0, s.GetMinB());
problem.SetParameterUpperBound(&result.B, 0, s.GetMaxB());
} else {
problem.SetParameterBlockConstant(&result.B);
}
// Only when the wedge is refined are mos/wedge parameter blocks in the problem. Bound the wedge
// and keep mosaicity fixed: the per-image fit is degenerate between G and mosaicity and collapses
// it toward its floor (3x too small), which corrupts the partiality.
if (model == PartialityModel::Rotation && refine_rot_wedge) {
problem.SetParameterLowerBound(&result.wedge, 0, s.GetMinWedge());
problem.SetParameterUpperBound(&result.wedge, 0, s.GetMaxWedge());
problem.SetParameterBlockConstant(&result.mos);
}
ceres::Solver::Options options;
options.linear_solver_type = ceres::DENSE_QR;
options.minimizer_progress_to_stdout = false;
options.num_threads = 1;
ceres::Solver::Summary summary;
ceres::Solve(options, &problem, &summary);
}
for (auto &r: integration_outcome.reflections) {
const double B_term = exp(result.B * -SafeInv(4.0 * r.d * r.d, 0.0));
switch (model) {
case PartialityModel::Unity:
r.partiality = 1.0;
break;
case PartialityModel::Rotation: {
if (std::isfinite(r.delta_phi_deg) && std::isfinite(r.zeta) && result.mos > 1e-6)
r.partiality = RotationPartiality(r.delta_phi_deg, r.zeta, result.mos, result.wedge);
break;
}
default:
// For fixed partiality there is no need to change anything
break;
}
const double denom = B_term * r.partiality * result.G;
if (std::isfinite(r.rlp) && std::isfinite(denom) && denom > 0.0) {
r.image_scale_corr = static_cast<float>(r.rlp / denom);
} else {
r.image_scale_corr = NAN;
}
}
const auto [cc, cc_n] = CalculateGlobalCC(integration_outcome.reflections);
result.cc = cc;
result.cc_n = cc_n;
auto end = std::chrono::steady_clock::now();
result.time_s = std::chrono::duration<float>(end - start).count();
integration_outcome.image_scale_cc = cc;
integration_outcome.image_scale_cc_n = cc_n;
integration_outcome.image_scale_g = result.G;
if (s.GetRefineB())
integration_outcome.image_scale_b_factor_Ang2 = result.B;
else
integration_outcome.image_scale_b_factor_Ang2.reset();
if (model == PartialityModel::Rotation) {
integration_outcome.mosaicity_deg = result.mos;
if (refine_rot_wedge)
integration_outcome.image_scale_wedge_deg = result.wedge;
else
integration_outcome.image_scale_wedge_deg.reset();
} else {
integration_outcome.mosaicity_deg.reset();
integration_outcome.image_scale_wedge_deg.reset();
}
}
void ScaleOnTheFly::Scale(std::vector<IntegrationOutcome> &integration, size_t nthreads) const {
if (nthreads == 0)
nthreads = std::thread::hardware_concurrency();
if (nthreads <= 1) {
for (auto & i : integration)
Scale(i);
} else {
auto local_nthreads = std::min(nthreads, integration.size());
std::vector<std::future<void>> futures;
futures.reserve(local_nthreads);
std::atomic<size_t> curr_image = 0;
for (size_t t = 0; t < local_nthreads; ++t)
futures.emplace_back(std::async(std::launch::async, [&] {
size_t i = curr_image.fetch_add(1);
while (i < integration.size()) {
Scale(integration[i]);
i = curr_image.fetch_add(1);
}
}));
for (auto &f: futures)
f.get();
}
}