From f4beffdf304ce4e07ff5b976922b710d12a3080e Mon Sep 17 00:00:00 2001
From: Dmitri Naumov <dmitri.naumov@ufz.de>
Date: Fri, 18 Oct 2024 16:37:30 +0200
Subject: [PATCH] [BL] allgather for single value; type conversion
---
BaseLib/MPI.h | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 48 insertions(+)
diff --git a/BaseLib/MPI.h b/BaseLib/MPI.h
index bdab781de42..de83e3fc4dd 100644
--- a/BaseLib/MPI.h
+++ b/BaseLib/MPI.h
@@ -51,5 +51,53 @@ struct Mpi
int size;
int rank;
};
+
+template <typename T>
+constexpr MPI_Datatype mpiType()
+{
+ using U = std::remove_const_t<T>;
+ if constexpr (std::is_same_v<U, bool>)
+ {
+ return MPI_C_BOOL;
+ }
+ if constexpr (std::is_same_v<U, char>)
+ {
+ return MPI_CHAR;
+ }
+ if constexpr (std::is_same_v<U, double>)
+ {
+ return MPI_DOUBLE;
+ }
+ if constexpr (std::is_same_v<U, float>)
+ {
+ return MPI_FLOAT;
+ }
+ if constexpr (std::is_same_v<U, int>)
+ {
+ return MPI_INT;
+ }
+ if constexpr (std::is_same_v<U, std::size_t>)
+ {
+ return MPI_UNSIGNED_LONG;
+ }
+ if constexpr (std::is_same_v<U, unsigned int>)
+ {
+ return MPI_UNSIGNED;
+ }
+}
+
+template <typename T>
+static std::vector<T> allgather(T const& value, Mpi const& mpi)
+{
+ std::vector<T> result(mpi.size);
+
+ result[mpi.rank] = value;
+
+ MPI_Allgather(&result[mpi.rank], 1, mpiType<T>(), result.data(), 1,
+ mpiType<T>(), mpi.communicator);
+
+ return result;
+}
+
#endif
} // namespace BaseLib::MPI
--
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