dask 2021.10.0

NotesParametersReturns
logistic(self, loc=0.0, scale=1.0, size=None, chunks='auto', **kwargs)

This docstring was copied from numpy.random.mtrand.RandomState.logistic.

Some inconsistencies with the Dask version may exist.

Samples are drawn from a logistic distribution with specified parameters, loc (location or mean, also median), and scale (>0).

note

New code should use the logistic method of a default_rng() instance instead; please see the :None:ref:`random-quick-start`.

Notes

The probability density for the Logistic distribution is

$$P(x) = P(x) = \frac{e^{-(x-\mu)/s}}{s(1+e^{-(x-\mu)/s})^2},$$

where $\mu$ = location and $s$ = scale.

The Logistic distribution is used in Extreme Value problems where it can act as a mixture of Gumbel distributions, in Epidemiology, and by the World Chess Federation (FIDE) where it is used in the Elo ranking system, assuming the performance of each player is a logistically distributed random variable.

Parameters

loc : float or array_like of floats, optional

Parameter of the distribution. Default is 0.

scale : float or array_like of floats, optional

Parameter of the distribution. Must be non-negative. Default is 1.

size : int or tuple of ints, optional

Output shape. If the given shape is, e.g., (m, n, k) , then m * n * k samples are drawn. If size is None (default), a single value is returned if loc and scale are both scalars. Otherwise, np.broadcast(loc, scale).size samples are drawn.

Returns

out : ndarray or scalar

Drawn samples from the parameterized logistic distribution.

Draw samples from a logistic distribution.

See Also

Generator.logistic

which should be used for new code.

scipy.stats.logistic

probability density function, distribution or cumulative density function, etc.

Examples

Draw samples from the distribution:

This example is valid syntax, but we were not able to check execution
>>> loc, scale = 10, 1  # doctest: +SKIP
... s = np.random.logistic(loc, scale, 10000) # doctest: +SKIP
... import matplotlib.pyplot as plt # doctest: +SKIP
... count, bins, ignored = plt.hist(s, bins=50) # doctest: +SKIP

# plot against distribution

This example is valid syntax, but we were not able to check execution
>>> def logist(x, loc, scale):  # doctest: +SKIP
...  return np.exp((loc-x)/scale)/(scale*(1+np.exp((loc-x)/scale))**2)
... lgst_val = logist(bins, loc, scale) # doctest: +SKIP
... plt.plot(bins, lgst_val * count.max() / lgst_val.max()) # doctest: +SKIP
... plt.show() # doctest: +SKIP
See :

Local connectivity graph

Hover to see nodes names; edges to Self not shown, Caped at 50 nodes.

Using a canvas is more power efficient and can get hundred of nodes ; but does not allow hyperlinks; , arrows or text (beyond on hover)

SVG is more flexible but power hungry; and does not scale well to 50 + nodes.

All aboves nodes referred to, (or are referred from) current nodes; Edges from Self to other have been omitted (or all nodes would be connected to the central node "self" which is not useful). Nodes are colored by the library they belong to, and scaled with the number of references pointing them


File: /dask/array/random.py#311
type: <class 'function'>
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