RandomState.exponential(scale=1.0, size=None)
Draw samples from an 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 [R152].
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 [R150], or the time between page requests to Wikipedia [R151].
Parameters: |
scale : float or array_like of floats The scale parameter, . size : int or tuple of ints, optional Output shape. If the given shape is, e.g., |
---|---|
Returns: |
out : ndarray or scalar Drawn samples from the parameterized exponential distribution. |
[R150] | (1, 2) Peyton Z. Peebles Jr., “Probability, Random Variables and Random Signal Principles”, 4th ed, 2001, p. 57. |
[R151] | (1, 2) Wikipedia, “Poisson process”, http://en.wikipedia.org/wiki/Poisson_process |
[R152] | (1, 2) Wikipedia, “Exponential distribution”, http://en.wikipedia.org/wiki/Exponential_distribution |
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https://docs.scipy.org/doc/numpy-1.13.0/reference/generated/numpy.random.RandomState.exponential.html