# Command: testsuite::test_spike_poisson_ps

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Name:

    testsuite::test_spike_poisson_ps - tests if spikes independent of resolution

Synopsis:

    (test_spike_poisson_ps) run -> compare with results at other resolutions

Description:

      The difference in spike times is exactly 0.0 between
      all resolutions.
      test_spike_poisson_ps_precision.sli
      already verified that spikes are produced and recorded with
      double resolution.

      This script will give identical results almost always, even if the resolution
      is not representable as a double. The main reason for this is that the
      poisson_generator_ps generates spikes without attention to resolution. This
      means that exactly the same sequence of spike times is generated internally
      in the generator independent of resolution. Rounding errors occur, if at all,
      only when the spike time is split into a multiple of the resolution and the
      offset. In this calculation, the resolution enters as a fixed multiple of tics.
      The calculation is reversed in the spike detector, when step-multiple and offset
      are recombined. This splitting and recombination apparently gives reproducible
      results. The only deviation observed was for two spikes at very early times (<0.01 ms)
      and coarse resolution (0.1 ms); total of 388.533 spikes tested. Therefore I
      introduced the check against the 1e-15 relative error limit below.

      If this test fails go back to
      test_spike_poisson_ps_precision.sli
      to check whether poisson_generator_ps can emit spike times at
      double precision or whether spike times are limited to the
      precision of a tic.

Author:

    Plesser, Diesmann

FirstVersion:

    February 2007

Source:

    /opt/conda/conda-bld/nest_1524088722951/work/nest-2.14.0/testsuite/unittests/test_spike_poisson_ps.sli

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