added parameter conversion

include/aare/AngleCalibration.hpp

@@ -1,3 +1,4 @@
+#include <algorithm>
 #include <cstdint>
 #include <fstream>
 #include <iostream>
@@ -15,13 +16,15 @@
 
 namespace aare {
 
+using parameters =
+    std::tuple<std::vector<double>, std::vector<double>, std::vector<double>>;
+
 // TODO: can i have a static struct, constexpr?
 struct MythenSpecifications {
 
     static constexpr int32_t max_modules = 48;
     static constexpr int32_t channels_per_module = 1280;
-    static constexpr double pitch =
-        0.05; // what is this pitch pitch is up e.g. rotation aroung y axis
+    static constexpr double pitch = 0.05; // strip width [mm] ?? TODO: not sure
     static constexpr double ttmin = -180.0; // what is this the angle
     static constexpr float ttmax = 180.0;
     static constexpr float ttstep =
@@ -41,12 +44,31 @@ class AngleCalibration {
         offsets.reserve(MythenSpecifications::max_modules);
     }
 
+    /** reads the historical Detector Group (DG) parameters from file **/
     void read_initial_calibration_from_file(const std::string &filename);
 
+    /** converts DG parameters to easy EE parameters e.g.geometric parameters */
+    parameters convert_to_EE_parameters();
+
+    /** converts DG parameters to easy BC parameters e.g. best computing
+     * parameters */
+    parameters convert_to_BC_parameters();
+
   protected:
-    std::vector<double> centers;
-    std::vector<double> conversions;
-    std::vector<double> offsets;
+    // TODO: Design maybe have a struct with three vectors, store all three sets
+    // of parameters
+
+    // TODO: check if interpretation and units are correct
+    // historical DG parameters
+    std::vector<double>
+        centers; // orthogonal projection of sample onto detector (given in
+                 // strip number) [mm] D/pitch
+    std::vector<double>
+        conversions; // pitch/(normal distance from sample to detector (R)) [mm]
+                     // //used for easy conversion
+    std::vector<double>
+        offsets; // position of strip zero relative to sample [degrees] phi -
+                 // 180/pi*D/R TODO: expected an arcsin(D/R)?
 };
 
 // read hdf5 files - > do they store the histogram? what angles do they store?
@@ -94,13 +116,33 @@ void AngleCalibration::read_initial_calibration_from_file(
         std::cerr << "Error: " << e.what()
                   << std::endl; // TODO: replace with log
     }
-
-    // angle_sign = signbit(conversion);
-    // signed_angles = std::abs(conversion);
-    // inverse_angles = 1./signed_angles
-    // store [centers, signed_conversions, offsets]
-    // dont know what conversion and offset is - dont know what calculations one
-    // does there the errors are actually not needed
 }
 
-} // namespace aare
+parameters AngleCalibration::convert_to_EE_parameters() {
+
+    // normal distance between sample and detector (R)
+    std::vector<double> normal_distances(centers.size());
+    // distances between intersection point of sample normal and module origin
+    // (D)
+    std::vector<double> module_center_distances(centers.size());
+    // angles between undiffracted beam and orthogonal sample projection on
+    // detector (phi)
+    std::vector<double> angles(centers.size());
+
+    for (size_t i = 0; i < centers.size(); ++i) {
+        normal_distances[i] = centers[i] * MythenSpecifications::pitch;
+        module_center_distances[i] =
+            MythenSpecifications::pitch / std::abs(conversions[i]);
+        angles[i] =
+            offsets[i] + 180.0 / M_PI * centers[i] * std::abs(conversions[i]);
+    }
+    // TODO: maybe add function rad_to_deg
+
+    return std::make_tuple(normal_distances, module_center_distances, angles);
+}
+/*
+parameters
+AngleCalibration::convert_to_BC_parameters() {}
+*/
+
+} // namespace aare