# Command: GetVpRNG

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Name:

    GetVpRNG - return random number generator associated to virtual process
      of node

Synopsis:

      gid GetVpRNG -> rngtype

Description:

      This function is helpful in the implementation of parallelized wiring
      routines that create identical random structures independent of the
      number of machines and threads participating in the simulation. The
      function is used in SLI libraries. There is probably no need to
      directly use GetVpRNG in scripts describing a particular simulation.

      In NEST each node (e.g. neuron) is assigned to a virtual process and
      each virtual process maintains its own random number generator. In a
      simulation run the virtual processes are equally distributed over the
      participating machines and threads as specified by the user. In NEST
      2.0 virtual processes are identified with threads.  Thus, with the
      option /total_num_virtual_procs of [0] set to n, there are in total
      always n threads (virtual processes) independent of the number of
      participating machines.  The concept of virtual processes is described
      in detail in [1].

      Identical results are achieved independent of the number of machines
      and threads participating in a simulation if all operations modifying
      a neuron and its incoming synapses use the random number generator of
      the virtual process the neuron is assigned to.

      An ArgumentTypeError is raised if GetVpRNG is called for a
      non-local gid.

Parameters:

      gid 	- global id of the node

References:

      [1] Morrison A, Mehring C, Geisel T, Aertsen A, and Diesmann M (2005)
      Advancing the boundaries of high connectivity network simulation
      with distributed computing. Neural Computation 17(8):1776-1801
      The article is available at www.nest-simulator.org

Author:

    Tobias Potjans, Moritz Helias, Diesmann

SeeAlso:

- GetGlobalRNG

Source:

    /opt/conda/conda-bld/nest_1512418773968/work/nest-2.14.0/nestkernel/nestmodule.cpp

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