common/Reflection.h

@@ -13,6 +13,7 @@ struct Reflection {
     int64_t k;
     int64_t l;
     float image_number; // Can be in-between for 3D integration
+    float angle_deg; // phi angle from XDS
     float predicted_x;
     float predicted_y;
     float d;

image_analysis/bragg_integration/BraggPredictionRotation.cpp

@@ -0,0 +1,209 @@
+// SPDX-FileCopyrightText: 2025 Filip Leonarski, Paul Scherrer Institute <filip.leonarski@psi.ch>
+// SPDX-License-Identifier: GPL-3.0-only
+
+#include "BraggPredictionRotation.h"
+
+#include <cmath>
+#include <algorithm>
+
+#include "../../common/DiffractionGeometry.h"
+#include "../../common/GoniometerAxis.h"
+#include "../../common/JFJochException.h"
+#include "SystematicAbsence.h"
+
+namespace {
+    inline float deg_to_rad(float deg) {
+        return deg * (static_cast<float>(M_PI) / 180.0f);
+    }
+    inline float rad_to_deg(float rad) {
+        return rad * (180.0f / static_cast<float>(M_PI));
+    }
+
+    // Solve A cos(phi) + B sin(phi) + D = 0, return solutions in [phi0, phi1]
+    // Returns 0..2 solutions.
+    inline int solve_trig(float A, float B, float D,
+                          float phi0, float phi1,
+                          float out_phi[2]) {
+        const float R = std::sqrt(A*A + B*B);
+        if (!(R > 0.0f))
+            return 0;
+
+        const float rhs = -D / R;
+        if (rhs < -1.0f || rhs > 1.0f)
+            return 0;
+
+        const float phi_ref = std::atan2(B, A);
+        const float delta = std::acos(rhs);
+
+        float s1 = phi_ref + delta;
+        float s2 = phi_ref - delta;
+
+        // Shift candidates by +/- 2*pi so they land near the interval.
+        const float two_pi = 2.0f * static_cast<float>(M_PI);
+        auto shift_near = [&](float x) {
+            while (x < phi0 - two_pi) x += two_pi;
+            while (x > phi1 + two_pi) x -= two_pi;
+            return x;
+        };
+
+        s1 = shift_near(s1);
+        s2 = shift_near(s2);
+
+        int n = 0;
+        if (s1 >= phi0 && s1 <= phi1) out_phi[n++] = s1;
+        if (s2 >= phi0 && s2 <= phi1) {
+            if (n == 0 || std::fabs(s2 - out_phi[0]) > 1e-6f) out_phi[n++] = s2;
+        }
+        return n;
+    }
+
+    // Convert angle to fractional image_number using goniometer start/increment
+    inline float phi_deg_to_image_number(float phi_deg, float start_deg, float increment_deg) {
+        return (phi_deg - start_deg) / increment_deg;
+    }
+} // namespace
+
+std::vector<Reflection> BraggPredictionRotation::Calc(const DiffractionExperiment& experiment,
+                                                        const CrystalLattice& lattice,
+                                                        const BraggPredictionRotationSettings& settings) const {
+    std::vector<Reflection> out;
+    out.reserve(200000); // tune
+
+    const auto gon_opt = experiment.GetGoniometer();
+    if (!gon_opt.has_value())
+        throw JFJochException(JFJochExceptionCategory::InputParameterInvalid,
+                              "BraggPredictionRotationCPU requires a goniometer axis");
+
+    const GoniometerAxis& gon = *gon_opt;
+    const auto geom = experiment.GetDiffractionGeometry();
+
+    // Determine prediction interval in spindle angle.
+    // We treat each image as [angle(image), angle(image)+wedge)
+    const float start_deg = gon.GetStart_deg();
+    const float inc_deg   = gon.GetIncrement_deg();
+    const float wedge_deg = gon.GetWedge_deg();
+
+    float phi0_deg = gon.GetAngle_deg(static_cast<float>(settings.image_first));
+    float phi1_deg = gon.GetAngle_deg(static_cast<float>(settings.image_last)) + wedge_deg;
+
+    if (settings.pad_one_wedge) {
+        phi0_deg -= wedge_deg;
+        phi1_deg += wedge_deg;
+    }
+
+    const float phi0 = deg_to_rad(phi0_deg);
+    const float phi1 = deg_to_rad(phi1_deg);
+
+    // Resolution cutoff in reciprocal space
+    const float one_over_dmax = 1.0f / settings.high_res_A;
+    const float one_over_dmax_sq = one_over_dmax * one_over_dmax;
+
+    // S0 has length 1/lambda (your convention)
+    const Coord S0 = geom.GetScatteringVector();
+    const float k2 = (S0 * S0); // (1/lambda)^2
+
+    // Rotation axis in lab frame (already normalized in ctor, but keep safe)
+    const Coord w = gon.GetAxis().Normalize();
+
+    const Coord Astar = lattice.Astar();
+    const Coord Bstar = lattice.Bstar();
+    const Coord Cstar = lattice.Cstar();
+
+    const float det_w = static_cast<float>(experiment.GetXPixelsNum());
+    const float det_h = static_cast<float>(experiment.GetYPixelsNum());
+
+    for (int h = -settings.max_hkl; h <= settings.max_hkl; ++h) {
+        const Coord Ah = Astar * static_cast<float>(h);
+
+        for (int k = -settings.max_hkl; k <= settings.max_hkl; ++k) {
+            const Coord AhBk = Ah + Bstar * static_cast<float>(k);
+
+            for (int l = -settings.max_hkl; l <= settings.max_hkl; ++l) {
+                if (systematic_absence(h, k, l, settings.centering))
+                    continue;
+
+                const Coord g0 = AhBk + Cstar * static_cast<float>(l);
+                const float g02 = g0 * g0;
+
+                if (!(g02 > 0.0f))
+                    continue;
+                if (g02 > one_over_dmax_sq)
+                    continue;
+
+                // g0 = g_par + g_perp wrt spindle axis
+                const float g_par_s = g0 * w;
+                const Coord g_par = w * g_par_s;
+                const Coord g_perp = g0 - g_par;
+
+                const float g_perp2 = g_perp * g_perp;
+                if (g_perp2 < 1e-12f) {
+                    // Rotation does not move this reciprocal vector: skip for now.
+                    // (Could be handled by checking whether it satisfies Ewald at all.)
+                    continue;
+                }
+
+                // Equation: |S0 + g(phi)|^2 = |S0|^2
+                // g(phi) = g_par + cos(phi) g_perp + sin(phi) (w x g_perp)
+                const Coord p = S0 + g_par;
+                const Coord w_x_gperp = w % g_perp;
+
+                const float A = 2.0f * (p * g_perp);
+                const float B = 2.0f * (p * w_x_gperp);
+                const float D = (p * p) + g_perp2 - k2;
+
+                float sols[2]{};
+                const int nsol = solve_trig(A, B, D, phi0, phi1, sols);
+                if (nsol == 0)
+                    continue;
+
+                for (int si = 0; si < nsol; ++si) {
+                    const float phi = sols[si];
+
+                    // Rotate g0 by phi about w
+                    const RotMatrix R(phi, w);
+                    const Coord g = R * g0;
+                    const Coord S = S0 + g;
+
+                    // Project to detector using canonical geometry code
+                    const auto [x, y] = geom.RecipToDector(g);
+                    if (!std::isfinite(x) || !std::isfinite(y))
+                        continue;
+                    if (x < 0.0f || x >= det_w || y < 0.0f || y >= det_h)
+                        continue;
+
+                    // Convert phi to fractional image number
+                    const float phi_deg = rad_to_deg(phi);
+
+                    Reflection r{};
+                    r.h = h;
+                    r.k = k;
+                    r.l = l;
+                    r.angle_deg = phi_deg;
+                    r.image_number = phi_deg_to_image_number(phi_deg, start_deg, inc_deg);
+                    r.predicted_x = x;
+                    r.predicted_y = y;
+                    r.d = 1.0f / std::sqrt(g02);
+
+                    // diagnostic: should be ~0
+                    r.dist_ewald = S.Length() - std::sqrt(k2);
+
+                    r.I = 0.0f;
+                    r.bkg = 0.0f;
+                    r.sigma = 0.0f;
+
+                    out.push_back(r);
+                }
+            }
+        }
+    }
+
+    std::sort(out.begin(), out.end(), [](const Reflection &a, const Reflection &b) {
+        if (a.angle_deg != b.angle_deg)
+            return a.angle_deg < b.angle_deg;
+        if (a.h != b.h) return a.h < b.h;
+        if (a.k != b.k) return a.k < b.k;
+        return a.l < b.l;
+    });
+
+    return out;
+}

image_analysis/bragg_integration/BraggPredictionRotation.h

@@ -0,0 +1,38 @@
+// SPDX-FileCopyrightText: 2025 Filip Leonarski, Paul Scherrer Institute <filip.leonarski@psi.ch>
+// SPDX-License-Identifier: GPL-3.0-only
+
+#ifndef JFJOCH_BRAGGPREDICTIONROTATION_H
+#define JFJOCH_BRAGGPREDICTIONROTATION_H
+
+#include <vector>
+#include <cstdint>
+
+#include "../../common/CrystalLattice.h"
+#include "../../common/DiffractionExperiment.h"
+#include "../../common/Reflection.h"
+
+struct BraggPredictionRotationSettings {
+    float high_res_A = 1.5f;
+    int max_hkl = 100;
+    char centering = 'P';
+
+    // Predict only in this image interval (inclusive)
+    int64_t image_first = 0;
+    int64_t image_last = 0;
+
+    // If true, expands [phi_start, phi_end] by one wedge on each side
+    // (useful if you later want to model partials / edge effects).
+    bool pad_one_wedge = false;
+};
+
+class BraggPredictionRotation {
+public:
+    BraggPredictionRotation() = default;
+
+    std::vector<Reflection> Calc(const DiffractionExperiment& experiment,
+                                 const CrystalLattice& lattice,
+                                 const BraggPredictionRotationSettings& settings) const;
+};
+
+
+#endif //JFJOCH_BRAGGPREDICTIONROTATION_H

image_analysis/bragg_integration/CMakeLists.txt

@@ -9,6 +9,8 @@ ADD_LIBRARY(JFJochBraggIntegration STATIC
         BraggPredictionFactory.cpp
         BraggPredictionFactory.h
         SystematicAbsence.h
+        BraggPredictionRotation.cpp
+        BraggPredictionRotation.h
 )
 
 TARGET_LINK_LIBRARIES(JFJochBraggIntegration JFJochCommon)