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| -rw-r--r-- | Docs/source/running_cpp/parameters.rst | 13 | ||||
| -rw-r--r-- | Source/WarpX.cpp | 18 |
2 files changed, 31 insertions, 0 deletions
diff --git a/Docs/source/running_cpp/parameters.rst b/Docs/source/running_cpp/parameters.rst index 73f613a73..0d599a261 100644 --- a/Docs/source/running_cpp/parameters.rst +++ b/Docs/source/running_cpp/parameters.rst @@ -44,6 +44,19 @@ Overall simulation parameters * ``warpx.verbose`` (`0` or `1`) Controls how much information is printed to the terminal, when running WarpX. +* ``warpx.random_seed`` (`string` or `int` > 0) optional + If provided ``warpx.random_seed = random``, the random seed will be determined + using `std::random_device` and `std::clock()`, + thus every simulation run produces different random numbers. + If provided ``warpx.random_seed = n``, and it is required that `n > 0`, + the random seed for each MPI rank is `(mpi_rank+1) * n`, + where `mpi_rank` starts from 0. + `n = 1` and ``warpx.random_seed = default`` + produce the default random seed. + Note that when GPU threading is used, + one should not expect to obtain the same random numbers, + even if a fixed ``warpx.random_seed`` is provided. + Setting up the field mesh ------------------------- diff --git a/Source/WarpX.cpp b/Source/WarpX.cpp index 8ffc22ea7..7d6637e38 100644 --- a/Source/WarpX.cpp +++ b/Source/WarpX.cpp @@ -340,6 +340,24 @@ WarpX::ReadParameters () { ParmParse pp("warpx"); + // set random seed + std::string random_seed = "default"; + pp.query("random_seed", random_seed); + if ( random_seed != "default" ) { + unsigned long myproc_1 = ParallelDescriptor::MyProc() + 1; + if ( random_seed == "random" ) { + std::random_device rd; + std::uniform_int_distribution<int> dist(2, INT_MAX); + unsigned long seed = myproc_1 * dist(rd); + ResetRandomSeed(seed); + } else if ( std::stoi(random_seed) > 0 ) { + unsigned long seed = myproc_1 * std::stoul(random_seed); + ResetRandomSeed(seed); + } else { + Abort("warpx.random_seed must be \"default\", \"random\" or an integer > 0."); + } + } + pp.query("cfl", cfl); pp.query("verbose", verbose); pp.query("regrid_int", regrid_int); |