v1.0.0-rc.41

image_analysis/IntegrationStats.cpp

@@ -0,0 +1,51 @@
+// SPDX-FileCopyrightText: 2025 Filip Leonarski, Paul Scherrer Institute <filip.leonarski@psi.ch>
+// SPDX-License-Identifier: GPL-3.0-only
+
+#include "IntegrationStats.h"
+#include "Regression.h"
+#include <cmath>
+
+IntegrationStats::IntegrationStats(float d_max_A, float d_min_A, int32_t in_nshells) {
+    d_min = d_min_A;
+    d_max = d_max_A;
+    one_over_dmax = 1.0f / (d_max);
+    one_over_dmin = 1.0f / (d_min);
+    nshells = in_nshells;
+    I.resize(nshells);
+    I_sigma.resize(nshells);
+    count.resize(nshells);
+}
+
+void IntegrationStats::AddReflection(const Reflection &r) {
+    if (r.d == 0.0f)
+        return;
+
+    float one_over_d = 1.0f / (r.d);
+    int64_t shell = std::lround((one_over_d - one_over_dmax) / (one_over_dmin - one_over_dmax)
+            * static_cast<float>(nshells));
+    if (shell >= 0 && shell < nshells) {
+        I.at(shell) += r.I;
+        I_sigma.at(shell) += r.I / r.sigma;
+        count.at(shell) += 1;
+    }
+}
+
+float IntegrationStats::BFactor() {
+    std::vector<float> x;
+    std::vector<float> y;
+
+    for (int i = 0; i < nshells; i++) {
+        if (count[i] == 0 || I[i] < 0.0)
+            continue;
+
+        float one_over_d = one_over_dmax
+                           + (static_cast<float>(i) + 0.5) * (one_over_dmin - one_over_dmax) / static_cast<float>(nshells);
+        x.push_back(one_over_d);
+        y.push_back(log(I[i] / count[i]));
+    }
+    if (!x.empty()) {
+        auto res = regression(x,y);
+        return -2.0f * res.slope;
+    } else
+        return 0.0;
+}