Module « numpy.random »

Fonction triangular - module numpy.random

Signature de la fonction triangular

Description

triangular.__doc__

        triangular(left, mode, right, size=None)

        Draw samples from the triangular distribution over the
        interval ``[left, right]``.

        The triangular distribution is a continuous probability
        distribution with lower limit left, peak at mode, and upper
        limit right. Unlike the other distributions, these parameters
        directly define the shape of the pdf.

        .. note::
            New code should use the ``triangular`` method of a ``default_rng()``
            instance instead; please see the :ref:`random-quick-start`.

        Parameters
        ----------
        left : float or array_like of floats
            Lower limit.
        mode : float or array_like of floats
            The value where the peak of the distribution occurs.
            The value must fulfill the condition ``left <= mode <= right``.
        right : float or array_like of floats
            Upper limit, must be larger than `left`.
        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 ``left``, ``mode``, and ``right``
            are all scalars.  Otherwise, ``np.broadcast(left, mode, right).size``
            samples are drawn.

        Returns
        -------
        out : ndarray or scalar
            Drawn samples from the parameterized triangular distribution.

        See Also
        --------
        Generator.triangular: which should be used for new code.

        Notes
        -----
        The probability density function for the triangular distribution is

        .. math:: P(x;l, m, r) = \begin{cases}
                  \frac{2(x-l)}{(r-l)(m-l)}& \text{for $l \leq x \leq m$},\\
                  \frac{2(r-x)}{(r-l)(r-m)}& \text{for $m \leq x \leq r$},\\
                  0& \text{otherwise}.
                  \end{cases}

        The triangular distribution is often used in ill-defined
        problems where the underlying distribution is not known, but
        some knowledge of the limits and mode exists. Often it is used
        in simulations.

        References
        ----------
        .. [1] Wikipedia, "Triangular distribution"
               https://en.wikipedia.org/wiki/Triangular_distribution

        Examples
        --------
        Draw values from the distribution and plot the histogram:

        >>> import matplotlib.pyplot as plt
        >>> h = plt.hist(np.random.triangular(-3, 0, 8, 100000), bins=200,
        ...              density=True)
        >>> plt.show()