qpCliqueNumber(qpgraph)
qpCliqueNumber()所属R语言包:qpgraph
Clique number
团数
译者:生物统计家园网 机器人LoveR
描述----------Description----------
Calculates the size of the largest maximal clique (the so-called clique number or maximum clique size) in a given undirected graph.
计算最大的(所谓的集团数量或最大团的大小)在一个给定的无向图的最大团的大小。
用法----------Usage----------
qpCliqueNumber(g, exact.calculation=TRUE, return.vertices=FALSE,
approx.iter=100, verbose=TRUE, R.code.only)
参数----------Arguments----------
参数:g
either a graphNEL object or an adjacency matrix of the given undirected graph.
无论是graphNEL对象或给定的无向图的邻接矩阵。
参数:exact.calculation
logical; if TRUE then the exact clique number is calculated; if FALSE then a lower bound is given instead.
逻辑;如果为TRUE,那么确切的团数计算;如果false,那么下限代替。
参数:return.vertices
logical; if TRUE a set of vertices forming a maximal clique of maximum size is returned; if FALSE only the maximum clique size is returned.
逻辑;如果实现,形成了一个最大规模的最大集团的顶点集返回;如果为FALSE返回最大团的大小。
参数:approx.iter
number of iterations to be employed in the calculation of the lower bound (i.e., only applies when exact.calculation=FALSE.
迭代次数,在计算下界(即只适用于exact.calculation=FALSE。
参数:verbose
show progress on calculations.
显示在计算方面取得的进展。
参数:R.code.only
logical; if FALSE then the faster C implementation is used (default); if TRUE then only R code is executed.
逻辑;如果为FALSE则更快的C实现使用(默认);如果TRUE,那么只有R代码被执行。
Details
详情----------Details----------
The calculation of the clique number of an undirected graph is one of the basic NP-complete problems (Karp, 1972) which means that its computational cost is bounded by an exponential running time (Pardalos and Xue, 1994). The current implementation uses C code from the GNU GPL Cliquer library by Niskanen and Ostergard (2003) based on the, probably the fastest to date, algorithm by Ostergard (2002).
一个无向图的团数的计算是一个基本的NP完全问题(卡普,1972年),这意味着其计算成本指数Pardalos和薛,运行时间(1994)界。当前实现使用Niskanen和Ostergard C代码(2003)的基础上,可能最快由Ostergard(2002年)的日期,算法从GNU GPL Cliquer图书馆的。
The lower bound on the maximum clique size is calculated by ranking the vertices by their connectivity degree, put the first vertex in a set and go through the rest of the ranking adding those vertices to the set that form a clique with the vertices currently within the set. Once the entire ranking has been examined a large clique should have been built and eventually one of the largests ones. This process is repeated a number of times (approx.iter) each of which the ranking is altered with increasing levels of randomness acyclically (altering 1 to $p$ vertices and again). Larger values of approx.iter should provide tighter lower bounds although it has been proven that no polynomial time algorithm can approximate the maximum clique size within a factor of n^ε (ε > 0), unless P=NP (Feige et al, 1991; Pardalos and Xue, 1994).
下界上最大的集团规模位居顶点的连接度计算,放在一组中的第一个顶点,并通过其余的排名加入的顶点集内形成一个顶点集团目前设置。一旦整个排名已审查大型集团应已建成并最终的largests的之一。这个过程反复多次(approx.iter),其中每个排名的改变与水平的不断提高,非循环的随机性(改变1 $ P $的顶点,并再次)。 approx.iter值越大,应提供更严格的下限,尽管它已被证明没有多项式时间算法可以近似n^ε(ε > 0),除非,P = NP的一个因素内最大的集团规模(飞鸽等,1991; Pardalos和薛,1994)。
值----------Value----------
a lower bound of the size of the largest maximal clique in the given graph, also known as its clique number.
下界又称作为其集团号码,图中最大的最大团的大小。
作者(S)----------Author(s)----------
R. Castelo
参考文献----------References----------
Gaussian graphical model search from microarray data with p larger than n. J. Mach. Learn. Res., 7:2621-2650, 2006.
Approximating the maximum clique is almost NP-Complete. Proc. 32nd IEEE Symp. on Foundations of Computer Science, 2-12, 1991.
computations, 43:85-103, 1972.
Communications Laboratory, Helsinki University of Technology, Espoo, Finland, Tech. Rep. T48, 2003. (http://users.tkk.fi/~pat/cliquer.html)
Discrete Appl. Math. 120:197-207, 2002.
J. Global Optim., 4:301-328, 1994.
参见----------See Also----------
qpClique
qpClique
举例----------Examples----------
require(graph)
nVar <- 50
set.seed(123)
g1 <- randomEGraph(V=as.character(1:nVar), p=0.3)
qpCliqueNumber(g1, verbose=FALSE)
g2 <- randomEGraph(V=as.character(1:nVar), p=0.7)
qpCliqueNumber(g2, verbose=FALSE)
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注:
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