Files
Jungfraujoch/image_analysis/bragg_integration/BraggIntegrationEngineGPU.h
T
leonarski_fandClaude Opus 5 6f7b136ec2 Bragg integration: a shared signal pixel belongs to the nearer reflection
Nothing kept a neighbour's flux out of a reflection's own signal disk. The union mask
keeps neighbour cores out of the BACKGROUND ring, but the r1 disk was read whole, so on
a dense pattern a crowded reflection measures part of its neighbour as its own.

Ownership is decided once per image into a per-pixel (quantised distance, reflection)
key written with an atomic minimum, so the nearest predicted centre wins whatever order
the writes arrive in and the lowest index breaks a tie. `--overlap exclude`, now the
default, drops the pixels a nearer neighbour owns from the profile fit. A profile fit is
the amplitude of a normalised profile, so leaving pixels out renormalises the estimator
by construction and the reflection stays unbiased rather than being discarded; the
summation-fallback guard is scaled back to the disk the box-sum seed actually read, so
it still compares like with like. `--overlap reject` is the XDS MINPK alternative - drop
the reflection when less than `--overlap-minpk` of its expected profile is cleanly its
own. A box sum has no profile to renormalise with, so `exclude` is a no-op there and
only `reject` acts on it.

Widening the split - keeping a pixel only where no other centre is within its distance
PLUS a margin - was built and measured, and it is worse monotonically: the residual bias
of the pixels that were kept grows from +0.072 to +0.209 in ln intensity at 0 to 3 px of
margin. What the margin removes is the reflection's own profile, not the neighbour's
tail, so the plain nearest-centre split is the rule.

Measured on the full 38-crystal rotation battery against the same binary with the
treatment off: ISa better 15 / worse 8, summed shortfall against XDS 39.7 -> 28.1. Three
of the losses are the two-pass loop taking its other branch - their median mosaicity
moves between the two known attractors - rather than the change under test; excluding
those it is better 15 / worse 5 and the shortfall goes 31.3 -> 14.4. The two crowded
crystals gain 38% and 52% of their ISa, one of them passing XDS. High-shell CC1/2 over
the 35 crystals that neither flipped branch nor carry a collapsed error model is better
7 / worse 7. Space groups unchanged at 35/38. The owner map is built only when a
treatment is asked for and costs 1.1% of the battery's wall clock - 23% on a genuinely
crowded crystal, nothing where no two predictions touch.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-08-11 05:02:31 +02:00

71 lines
3.8 KiB
C++

// SPDX-FileCopyrightText: 2026 Filip Leonarski, Paul Scherrer Institute <filip.leonarski@psi.ch>
// SPDX-License-Identifier: GPL-3.0-only
#pragma once
#include <cstdint>
#include <memory>
#include <vector>
#include "BraggIntegrationEngine.h"
#include "../indexing/CUDAMemHelpers.h"
// CUDA engine: reproduces BraggIntegrationEngineCPU up to floating-point precision. Each stage is a
// kernel with one CUDA block per reflection cooperating over the small window via shared-memory
// reductions (the natural mapping for thousands of independent, tiny per-spot integrations).
//
// Pipeline (profile modes): reset -> mark_mask -> boxsum -> learn_profile -> build_profiles -> fit
// (the resolution shell is computed inline, so there is no separate shell pass). BoxSum mode stops
// after boxsum (that pass is the BraggIntegrate2D box integrator and the seed of the profile fit).
// The preprocessed image already lives on the device (ImagePreprocessorBufferGPU::getGPUBuffer());
// only the per-frame predicted centres are uploaded.
class BraggIntegrationEngineGPU : public BraggIntegrationEngine {
std::shared_ptr<CudaStream> stream;
int threads;
size_t fit_shared_bytes;
int rad_w = 0; // radial-background window of boxsum, in bins of one pixel
size_t boxsum_shared_bytes = 0;
size_t capacity = 0; // per-reflection device/host arrays hold at least this many reflections
// --- per-reflection device arrays (grown by EnsureCapacity) ---
CudaDevicePtr<float> d_px_x, d_px_y, d_d;
CudaDevicePtr<int> d_cx, d_cy;
CudaDevicePtr<float> d_I, d_sigma, d_bkg, d_bkg_var, d_var_bkg, d_obs_x, d_obs_y;
CudaDevicePtr<float> d_isum; // box-sum raw sum, for the radial correction
CudaDevicePtr<int> d_ninner, d_rbin, d_kbin;
CudaDevicePtr<uint8_t> d_ok, d_strong, d_has_obs;
// --- radial background curvature correction (see BraggIntegrationEngine) ---
int n_rad = 0; // radial bins, 0 when the correction is off
CudaDevicePtr<float> d_rad_sum, d_k_diff;
CudaDevicePtr<int> d_rad_cnt;
// --- fixed-size device arrays ---
// The learning/fit math is single precision: FP64 is heavily throttled on consumer GPUs and the
// extraction is Poisson-noise limited, so float reproduces the double CPU path to ~1e-4.
CudaDevicePtr<uint8_t> d_mask; // per-pixel inner-stencil reflection mask
// Per-pixel (distance, reflection) key naming the nearest predicted centre; allocated only when
// an overlap treatment is on, so the default path costs no extra device memory.
CudaDevicePtr<uint32_t> d_owner;
CudaDevicePtr<float> d_shell_grid, d_global_grid; // learned profile accumulators (N_SHELL*GG, GG)
CudaDevicePtr<float> d_shell_P, d_global_P; // normalised profiles (empirical mode)
CudaDevicePtr<float> d_mom; // learned 2nd moments, 3 per shell + global
CudaDevicePtr<float> d_sigma2_r, d_sigma2_t; // radial/tangential widths, N_SHELL + global
CudaDevicePtr<int> d_shell_n, d_global_n;
CudaDevicePtr<unsigned long long> d_invd2; // [min,max] inv-d^2 as monotonic bit patterns
// --- host staging (copied back once per frame) ---
std::vector<float> h_px_x, h_px_y, h_d;
std::vector<float> h_I, h_sigma, h_bkg, h_var_bkg, h_obs_x, h_obs_y;
std::vector<uint8_t> h_ok, h_has_obs;
void EnsureCapacity(size_t n);
public:
BraggIntegrationEngineGPU(const DiffractionExperiment &experiment, std::shared_ptr<CudaStream> stream);
std::vector<Reflection> Run(const ImagePreprocessorBuffer &image,
const std::vector<Reflection> &predicted, size_t npredicted,
int64_t image_number) override;
};