方法
random.Generator.
vonmises
从von mises分布中提取样本。
样本是从冯米塞斯分布中提取的,在间隔上具有指定的模式(mu)和分散度(kappa)。 [-pi, pi] .
冯米塞斯分布(又称圆正态分布)是单位圆上的连续概率分布。它可以被认为是正态分布的圆形类似物。
分布模式(“中心”)。
分布的分散度,必须大于等于0。
输出形状。如果给定的形状是,例如, (m, n, k) 然后 m * n * k 取样。如果尺寸是 None (默认),如果 mu 和 kappa 都是标量。否则, np.broadcast(mu, kappa).size 取样。
(m, n, k)
m * n * k
None
mu
kappa
np.broadcast(mu, kappa).size
从参数化von mises分布中提取样本。
参见
scipy.stats.vonmises
概率密度函数、分布或累积密度函数等。
笔记
冯米塞斯分布的概率密度是
System Message: WARNING/2 (p(x)=\frac e^ \kappa cos(x-\mu)2\p i i_0(\kappa),)
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Package inputenc Error: Unicode character ( (U+FF08) (inputenc) not set up for use with LaTeX. See the inputenc package documentation for explanation. Type H <return> for immediate help. ... l.14 ...-\mu)2\p i i_0(\kappa),\end{split} ! Package inputenc Error: Unicode character ) (U+FF09) (inputenc) not set up for use with LaTeX. See the inputenc package documentation for explanation. Type H <return> for immediate help. ... l.14 ...-\mu)2\p i i_0(\kappa),\end{split} ! Package inputenc Error: Unicode character , (U+FF0C) (inputenc) not set up for use with LaTeX. See the inputenc package documentation for explanation. Type H <return> for immediate help. ... l.14 ...-\mu)2\p i i_0(\kappa),\end{split} ! Missing } inserted. <inserted text> } l.14 ...-\mu)2\p i i_0(\kappa),\end{split} ! Package inputenc Error: Unicode character ( (U+FF08) (inputenc) not set up for use with LaTeX. See the inputenc package documentation for explanation. Type H <return> for immediate help. ... l.14 ...-\mu)2\p i i_0(\kappa),\end{split} ! Package inputenc Error: Unicode character ) (U+FF09) (inputenc) not set up for use with LaTeX. See the inputenc package documentation for explanation. Type H <return> for immediate help. ... l.14 ...-\mu)2\p i i_0(\kappa),\end{split} ! Missing { inserted. <to be read again> } l.14 ...-\mu)2\p i i_0(\kappa),\end{split} ! Package inputenc Error: Unicode character ( (U+FF08) (inputenc) not set up for use with LaTeX. See the inputenc package documentation for explanation. Type H <return> for immediate help. ... l.14 ...-\mu)2\p i i_0(\kappa),\end{split} ! Package inputenc Error: Unicode character ) (U+FF09) (inputenc) not set up for use with LaTeX. See the inputenc package documentation for explanation. Type H <return> for immediate help. ... l.14 ...-\mu)2\p i i_0(\kappa),\end{split} ! Undefined control sequence. <argument> ...=\frac e^ \kappa cos(x-\mu )2\p i i_0(\kappa ),\end ... l.14 ...-\mu)2\p i i_0(\kappa),\end{split} ! Package inputenc Error: Unicode character ( (U+FF08) (inputenc) not set up for use with LaTeX. See the inputenc package documentation for explanation. Type H <return> for immediate help. ... l.14 ...-\mu)2\p i i_0(\kappa),\end{split} ! Package inputenc Error: Unicode character ) (U+FF09) (inputenc) not set up for use with LaTeX. See the inputenc package documentation for explanation. Type H <return> for immediate help. ... l.14 ...-\mu)2\p i i_0(\kappa),\end{split} ! Package inputenc Error: Unicode character , (U+FF0C) (inputenc) not set up for use with LaTeX. See the inputenc package documentation for explanation. Type H <return> for immediate help. ... l.14 ...-\mu)2\p i i_0(\kappa),\end{split} ! Missing } inserted. <inserted text> } l.14 ...-\mu)2\p i i_0(\kappa),\end{split} [1] (./math.aux) ) (see the transcript file for additional information) Output written on math.dvi (1 page, 448 bytes). Transcript written on math.log.
在哪里? 是模式和 分散,以及 是0阶的修正贝塞尔函数。
米塞斯是以理查德·埃德勒·冯·米塞斯命名的,他出生于奥匈帝国,现在的乌克兰。他于1939年逃到美国,成为哈佛大学的教授。他从事概率论、空气动力学、流体力学和科学哲学。
工具书类
Abramowitz,M.和Stegun,I.A.(编辑)。《数学函数与公式、图表和数学表手册》,第9版,纽约:多佛,1972年。
冯米塞斯,R.,“概率与统计的数学理论”,纽约:学术出版社,1964年。
实例
从分发中抽取样本:
>>> mu, kappa = 0.0, 4.0 # mean and dispersion >>> s = np.random.default_rng().vonmises(mu, kappa, 1000)
显示样本的直方图,以及概率密度函数:
>>> import matplotlib.pyplot as plt >>> from scipy.special import i0 >>> plt.hist(s, 50, density=True) >>> x = np.linspace(-np.pi, np.pi, num=51) >>> y = np.exp(kappa*np.cos(x-mu))/(2*np.pi*i0(kappa)) >>> plt.plot(x, y, linewidth=2, color='r') >>> plt.show()