rndGumbel
==============================================

Purpose
----------------

Computes Gumbel distributed random numbers with a choice of underlying random number generator.

Format
----------------
.. function:: r = rndGumbel(rows, cols, location, scale)
              { r, newstate } = rndGumbel(rows, cols, location, scale, state)

    :param rows: number of rows of resulting matrix.
    :type rows: scalar

    :param cols: number of columns of resulting matrix.
    :type cols: scalar

    :param location: location parameter, scalar or ExE conformable matrix with *rows* and *cols*
    :type location: scalar or matrix

    :param scale: scaler parameter, scalar or ExE conformable matrix with *rows* and *cols*
    :type scale: scalar or matrix

    :param state: Optional argument.

        **scalar case**

            *state* = starting seed value only. If -1, GAUSS computes the starting seed based on the system clock.

        **opaque vector case**

        *state* = the state vector returned from a previous call to one of the ``rnd`` random number functions.

    :type state: scalar or opaque vector

    :return r: Gumbel distributed random numbers.

    :rtype r: rows x cols matrix

    :return newstate: the updated state.

    :rtype newstate: Opaque vector

Remarks
-------

This function uses the definition of the Gumbel distribution
corresponding to the minimum extreme. The properties of the
pseudo-random numbers in *y* are:

.. math::

   E(y) = location - \gamma*scale \approx\\
   location - 0.5772*scale\\
   \gamma = \text{Euler-Mascheroni constant}\\
   Var(y) = \frac{(\pi*scale)^2}{6}

*r* and *c* will be truncated to integers if necessary.

.. seealso:: Functions :func:`rndCreateState`, :func:`rndStateSkip`