create flat top class

src/Distribution/FlatTop.hpp

+#ifndef IPPL_FLAT_TOP_H
+#define IPPL_FLAT_TOP_H
+
+#include "Distribution.h"
+#include "SamplingBase.hpp"
+#include <memory>
+
+using ParticleContainer_t = ParticleContainer<double, 3>;
+using FieldContainer_t = FieldContainer<double, 3>;
+using Distribution_t = Distribution;
+using GeneratorPool = typename Kokkos::Random_XorShift64_Pool<>;
+using Dist_t = ippl::random::NormalDistribution<double, 3>;
+
+class FlatTop : public SamplingBase {
+public:
+    FlatTop(std::shared_ptr<ParticleContainer_t> &pc, std::shared_ptr<FieldContainer_t> &fc, std::shared_ptr<Distribution_t> &opalDist)
+        : SamplingBase(pc, fc, opalDist) {}
+
+    using Matrix_t = ippl::Vector< ippl::Vector<double, 6>, 6>;
+
+    Vector_t<double, 3> muR_m, muP_m;
+    Matrix_t cov_m;
+    Matrix_t L_m;
+
+    Vector_t<double, 3> rmin_m;
+    Vector_t<double, 3> rmax_m;
+    Vector_t<double, 3> pmin_m;
+    Vector_t<double, 3> pmax_m;
+
+    Vector_t<double, 3> normRmin_m;
+    Vector_t<double, 3> normRmax_m;
+    Vector_t<double, 3> normPmin_m;
+    Vector_t<double, 3> normPmax_m;
+
+    Vector_t<double, 6> min_m;
+    Vector_t<double, 6> max_m;
+
+    Vector_t<double, 6> normMin_m;
+    Vector_t<double, 6> normMax_m;
+
+    void generateUniformDisk(size_t& numberOfParticles) {
+        GeneratorPool rand_pool64((size_t)(Options::seed + 100 * ippl::Comm->rank()));
+
+        view_type &Rview = pc_m->R.getView();
+        view_type &Pview = pc_m->P.getView();
+
+       // TODO: sample (Rx,Ry) uniformly on a disk of radius.
+       // TODO: then, scale Rx and Ry with sigmaR_m[0] and sigmaR_m[1]
+       // TODO: set Px=Py=0
+
+    }
+
+    void generateLongFlattopT(size_t& numberOfParticles){
+
+        view_type &Rview = pc_m->R.getView();
+        view_type &Pview = pc_m->P.getView();
+        auto &Dtview = pc_m->dt.getView();
+
+       // TODO: sample particle time according to the flat top profile
+       // TODO: set Rz=Pz to zero
+    }
+
+    void generateParticles(size_t& numberOfParticles, Vector_t<double, 3> nr) override {
+
+        GeneratorPool rand_pool64((size_t)(Options::seed + 100 * ippl::Comm->rank()));
+
+        generateUniformDisk(numberOfParticles);
+
+        generateLongFlattopT(numberOfParticles);
+    }
+};
+#endif

src/Track/TrackRun.cpp

@@ -34,6 +34,8 @@
 
 #include "Distribution/MultiVariateGaussian.hpp"
 
+#include "Distribution/FlatTop.hpp"
+
 #include "Physics/Physics.h"
 #include "Physics/Units.h"