Add MPI intraface class

Start parallelzationo

src/mpi_interface/MPI_Interface.cpp

+MPI_Interface::MPI_Interface() : boost::mpi::communicator()
+{}
+
+std::array<int, 2> MPI_Interface::get_start_end_from_list(int size, int start)
+{
+    int els_per_rank = size / size();
+    int remaineder = size % size();
+
+    std::array<int, 2> start_end;
+    start_end[0] = start + els_per_rank * rank() + std::min(rank(), remaineder);
+    start_end[1] = start + els_per_rank * (rank() + 1) + std::min(rank() + 1, remaineder);
+
+    return start_end;
+}

src/mpi_interface/MPI_Interface.hpp

+#ifndef SISSO_MPI_INTERFACE
+#define SISSO_MPI_INTERFACE
+
+#include <boost/mpi.hpp>
+#include <array>
+
+extern boost::mpi::environment env;
+namespace mpi = boost::mpi;
+
+// Augment the boost mpi communicator class with some other useful data
+/**
+ * @brief Augment the boost MPI communicator class with some other useful data
+ * @details MPI communicator used to transfer data throughout the cell.
+ *
+ */
+class MPI_Interface : public boost::mpi::communicator
+{
+public:
+    /**
+     * @brief      Constructor for the MPI_Interface
+     */
+    MPI_Interface();
+
+    std::array<int, 2> get_start_end_from_list(int size, int start);
+
+    /**
+     * @brief      Unique int tag generator
+     *
+     * @param[in]  procSend   sending process
+     * @param[in]  procRecv   receiving process
+     * @param[in]  maxOffest  number of different communication processes possible between two processes within the same operation
+     * @param[in]  offest     the assigned offset corresponding to a single communication within the same operation
+     *
+     * @return     A unique tag to send information between two processes
+     */
+    int cantorTagGen(unsigned int procSend, unsigned int procRecv, unsigned int maxOffest, unsigned int offest) { return (int((procSend + procRecv) * (procSend + procSend +1) / 2) + procRecv) * maxOffest + offest; }
+
+
+};
+
+#endif
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