warp.poisson
============

.. function:: warp._src.lang.poisson(state: uint32, lam: float32) -> uint32

   .. hlist::
      :columns: 8

      * Kernel
      * Python

   Generate a random sample from a Poisson distribution.
   
   In a kernel, advances ``state`` in place when ``lam > 0`` (and returns ``0``
   without consuming RNG state when ``lam == 0``); called from the Python scope, it
   does not modify ``state``, so repeated calls with the same ``state`` return the
   same count (see :func:`rand_init`). The returned count has mean and variance
   both equal to ``lam``.
   
   .. code-block:: python
   
       @wp.kernel
       def counts(seed: int, rate: float, out: wp.array[wp.uint32]):
           i = wp.tid()
           rng = wp.rand_init(seed, i)
           out[i] = wp.poisson(rng, rate)
   
   :param state: RNG state; advanced in place when called in a kernel (see :func:`rand_init`).
   :param lam: Expected value (rate) of the distribution; must be non-negative.
   
   :returns: A ``uint32`` sample drawn from ``Poisson(lam)``.