numpy.random.RandomState.exponential¶

RandomState.exponential(scale=1.0, size=None)

Exponential distribution.

Its probability density function is

for x > 0 and 0 elsewhere. is the scale parameter, which is the inverse of the rate parameter . The rate parameter is an alternative, widely used parameterization of the exponential distribution [R132].

The exponential distribution is a continuous analogue of the geometric distribution. It describes many common situations, such as the size of raindrops measured over many rainstorms [R130], or the time between page requests to Wikipedia [R131].

Parameters : scale : float The scale parameter, . size : tuple of ints Number of samples to draw. The output is shaped according to size.

References

 [R130] (1, 2) Peyton Z. Peebles Jr., “Probability, Random Variables and Random Signal Principles”, 4th ed, 2001, p. 57.
 [R131] (1, 2) “Poisson Process”, Wikipedia, http://en.wikipedia.org/wiki/Poisson_process
 [R132] (1, 2) “Exponential Distribution, Wikipedia, http://en.wikipedia.org/wiki/Exponential_distribution

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