rStrauss(spatstat)
rStrauss()所属R语言包:spatstat
Perfect Simulation of the Strauss Process
完美的模拟施特劳斯进程
译者:生物统计家园网 机器人LoveR
描述----------Description----------
Generate a random pattern of points, a simulated realisation of the Strauss process, using a perfect simulation algorithm.
生成点,模拟实现的施特劳斯进程,使用一个完美的模拟算法的随机图案。
用法----------Usage----------
rStrauss(beta, gamma = 1, R = 0, W = owin())
参数----------Arguments----------
参数:beta
intensity parameter (a positive number).
强度参数(正数)。
参数:gamma
interaction parameter (a number between 0 and 1, inclusive).
相互作用参数(在0和1之间,其中包括了一些)。
参数:R
interaction radius (a non-negative number).
相互作用半径(一个非负的数)。
参数:W
window (object of class "owin") in which to generate the random pattern. Currently this must be a rectangular window.
窗口(对象类"owin")在其中生成的随机模式。目前,这必须是一个矩形窗口。
Details
详细信息----------Details----------
This function generates a realisation of the Strauss point process in the window W using a "perfect simulation" algorithm.
这个函数生成一个窗口W使用一个“完美的模拟算法实现的斯特劳斯点的过程中。
The Strauss process (Strauss, 1975; Kelly and Ripley, 1976) is a model for spatial inhibition, ranging from a strong "hard core" inhibition to a completely random pattern according to the value of gamma.
施特劳斯过程(斯特劳斯,1975年,凯利和里普利,1976)是一个模型的空间抑制,范围从一个强大的硬核抑制根据的价值gamma一个完全随机的模式。
The Strauss process with interaction radius R and parameters beta and gamma is the pairwise interaction point process with probability density
施特劳斯过程中的相互作用半径R和参数beta和gamma是对相互作用过程的概率密度点
where x[1],…,x[n] represent the points of the pattern, n(x) is the number of points in the pattern, s(x) is the number of distinct unordered pairs of points that are closer than R units apart, and alpha is the normalising constant. Intuitively, each point of the pattern contributes a factor beta to the probability density, and each pair of points closer than r units apart contributes a factor gamma to the density.
x[1],…,x[n]代表的模式,n(x)是模式中的点的数量,s(x)是多少的点,比R的不同无序对单位外,和alpha是的标准化不变。直观地说,每一个点的图案比beta单元贡献的因素r的概率密度,以及每对点接近,除了有助于一个因素gamma的密度。
The interaction parameter gamma must be less than or equal to 1 in order that the process be well-defined (Kelly and Ripley, 1976). This model describes an “ordered” or “inhibitive” pattern. If gamma=1 it reduces to a Poisson process (complete spatial randomness) with intensity beta. If gamma=0 it is called a “hard core process” with hard core radius R/2, since no pair of points is permitted to lie closer than R units apart.
相互作用参数gamma必须小于或等于1的过程定义(凯利和Ripley,1976)。该模型描述了一个“有序”或“抑制”的格局。如果gamma=1降低到泊松过程(完整的空间是随机的)与强度beta。如果gamma=0它被称为“硬核过程”硬核半径R/2,因为没有对点被允许接近R单位除了撒谎。
The simulation algorithm used to generate the point pattern is "dominated coupling from the past" as implemented by Berthelsen and Moller (2002, 2003). This is a "perfect simulation" or "exact simulation" algorithm, so called because the output of the algorithm is guaranteed to have the correct probability distribution exactly (unlike the Metropolis-Hastings algorithm used in rmh, whose output is only approximately correct).
算法的仿真,用于生成的点图案是“主导从过去的实施Berthelsen和Moller(2002年,2003年)的耦合。这是一个“完美的模拟”或“精确模拟算法,所谓的,因为输出的算法是保证有正确的概率分布完全相同(不同的Metropolis-Hastings算法,其使用rmh,其输出是大约只有正确)。
There is a tiny chance that the algorithm will run out of space before it has terminated. If this occurs, an error message will be generated.
有一个微小的机会,该算法将空间用完之前,它已经终止。如果发生这种情况,将产生一条错误消息。
值----------Value----------
A point pattern (object of class "ppp").
点模式(类的对象"ppp")。
(作者)----------Author(s)----------
Kasper Klitgaard Berthelsen,
adapted for <span class="pkg">spatstat</span> by Adrian Baddeley
<a href="mailto:Adrian.Baddeley@csiro.au">Adrian.Baddeley@csiro.au</a>
<a href="http://www.maths.uwa.edu.au/~adrian/">http://www.maths.uwa.edu.au/~adrian/</a>
参考文献----------References----------
A primer on perfect simulation for spatial point processes. Bulletin of the Brazilian Mathematical Society 33, 351-367.
Likelihood and non-parametric Bayesian MCMC inference for spatial point processes based on perfect simulation and path sampling. Scandinavian Journal of Statistics 30, 549-564.
On Strauss's model for clustering. Biometrika 63, 357–360.
Statistical Inference and Simulation for Spatial Point Processes. Chapman and Hall/CRC.
A model for clustering. Biometrika 63, 467–475.
参见----------See Also----------
rmh, Strauss, rHardcore, rStraussHard, rDiggleGratton, rDGS.
rmh,Strauss,rHardcore,rStraussHard,rDiggleGratton,rDGS。
实例----------Examples----------
X <- rStrauss(0.05,0.2,1.5,square(141.4))
Z <- rStrauss(100,0.7,0.05)
转载请注明:出自 生物统计家园网(http://www.biostatistic.net)。
注:
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