Gompertz distribution

The probability density function for the gompertz distribution is:

.. math::

f(x, k) = \exp(-(x + e^{-x}))

where :math:x \ge 0, k > 0.

The cumulative distribution function is:

.. math::

F(x, k) = 1 - \exp(k(1-e^{x}))

The following plots show the pdf and cdf:

.. image:: ../../../../tests/imgs/stats/continuous/gompertz/gompertzpdf.png :align: center :width: 480

.. image:: ../../../../tests/imgs/stats/continuous/gompertz/gompertzcdf.png :align: center :width: 480