st.2logL.profile(sn)
st.2logL.profile()所属R语言包：sn
Profile twice loglikelihood for skew-t models
简介的两倍loglikelihood为歪斜T车型
译者：生物统计家园网 机器人LoveR
描述----------Description----------
Computation and plot of 1-dimensional and 2-dimensional profile (negative) twice log-likelihood function for skew-t regression models.
1维和2维轮廓（负）两次log歪斜-T的回归模型的似然函数的计算和绘图。
用法----------Usage----------
st.2logL.profile(X=matrix(rep(1, n)), y, freq, trace=FALSE,
fixed.comp = c(ncol(X)+2, ncol(X)+3),
fixed.values = cbind(c(-4,4), log(c(1,25))),
npts=51/length(fixed.comp), plot.it=TRUE, ...)
参数----------Arguments----------
参数：X
a matrix of explanatory variables; must have nrow(X) equal to length(y). Missing values (NA) are not allowed. If X is missing, a one-column matrix of 1's is created.
解释变量的矩阵必须有nrow(X)等于length(y)。遗漏值（NA）是不允许的。 X如果丢失，创建一列矩阵的1。
参数：y
a numeric vector. Missing values (NAs) are not allowed.
一个数值向量。遗漏值（NAS）是不允许的。
参数：freq
a vector of weights. If missing, a vector of 1's is created; otherwise it must have the same length of y.
的权重的矢量。如果缺少，一个向量的1的创建;y否则它必须具有相同的长度。
参数：trace
logical value which controls printing of the algorithm convergence. If trace=TRUE, details are printed. Default value is FALSE.
逻辑控制打印算法的收敛值。如果trace=TRUE，细节被打印出来。默认值为FALSE。
参数：fixed.comp
a vector containing the subset of the parameters for which the profile log-likelihood function is required; it can be of length 1 or 2. The set of components of the parameters are beta, log(omega), alpha, log(df), where beta represents the regression parameters and has ncol(X) components.
一个向量，包含需要更新对数似然函数的参数的子集，它可以是长度为1或2。的一组参数的组成部分，是beta, log(omega), alpha, log(df)，beta回归参数和ncol(X)组件。
参数：fixed.values
a numeric vector of values or a matrix with two columns, giving the range spanned by the selected parameters.
一个数值向量的值或两列的矩阵，由选定的参数的范围跨越。
参数：npts
number of points on each parameter interval for which the function must be evaluated.
数必须评估函数的每个参数间隔点。
参数：plot.it
logical value; if plot.it=TRUE (default value) a graphical display is produced.
逻辑值，如果plot.it=TRUE（默认值）的图形显示。
参数：...
graphical parameter passed either to plot or to contour, depending on whether lenght(fixed.comp) is 1 or 2. </table>
图形参数传递到plot或contour，取决于是否lenght(fixed.comp)是1或2。 </ TABLE>
值----------Value----------
A list containing the following components: <table summary="R valueblock"> <tr valign="top"><td>call</td> <td> the matched call. </td></tr> <tr valign="top"><td>param1</td> <td> vector of values of the first parameters values where the function has been evaluated. </td></tr> <tr valign="top"><td>param2</td> <td> vectors of the parameters values where the function has been evaluated. If length(fixed.comp)=1, the second vector contains NAs. </td></tr> <tr valign="top"><td>deviance</td> <td> a vector or a matrix which represents twice the negative relative profile loglikelihood; this is in the "relative" version, i.e. setting the maximum value to be 0. </td></tr> <tr valign="top"><td>max.logL</td> <td> a numeric value with the maximum which has been added to obtain the "relative" version of deviance. </td></tr> <tr valign="top"><td>best</td> <td> a list with the output of optim at the best evaluated point, that is the one with higher log-likelihood. </td></tr></table>
一个列表，其中包含以下组件：<table summary="R valueblock"> <tr valign="top"> <TD> call</ TD> <TD>匹配的呼叫。 </ TD> </ TR> <tr valign="top"> <TD>param1</ TD> <TD>向量的值的第一个参数值，其中的功能进行了评估。 </ TD> </ TR> <tr valign="top"> <TD>param2 </ TD> <TD>向量的参数值的功能进行了评估。如果length(fixed.comp)=1，第二个向量包含：NA的。 </ TD> </ TR> <tr valign="top"> <TD> deviance</ TD> <TD>这是在一个向量或矩阵，它代表两次的负相关个人资料loglikelihood;“相对“的版本，也就是说的最大的值设置为0。 </ TD> </ TR> <tr valign="top"> <TD> max.logL</ TD> <td>一个数值的最大已被添加到获得“相对”版本的 deviance。 </ TD> </ TR> <tr valign="top"> <TD> best</ TD> <td>一个列表的输出optim评价最好的点，也就是一个较高的对数似然。 </ TD> </ TR> </ TABLE>
副作用----------Side Effects----------
If plot.it=TRUE, a plot of the profile twice relative loglikeliood is produced on a graphical device. If length(fixed.comp)=1, a plot of the "deviance" is produced as a function of the chosen parameter component. If length(fixed.comp)=2, this plot takes the form of a contour plot whose contour lines correspond to confidence regions of approximate probability levels c(0.25, 0.5, 0.75, 0.90,0.95, 0.99).
如果plot.it=TRUE，一个图的轮廓两次相对loglikeliood是一个图形化的设备上。如果length(fixed.comp)=1，产生作为所选择的参数组分的函数的曲线图的“越轨”。如果length(fixed.comp)=2，该图的等高线图的形式，其轮廓线对应的置信区间的近似概率水平c(0.25, 0.5, 0.75, 0.90,0.95, 0.99)。
背景----------Background----------
The family of skew-t distributions is an extension of the Student's t family, via the introduction of a shape parameter which regulates skewness; when shape=0, the skew-t distribution reduces to the usual t distribution. A multivariate version of the distribution exists. See the reference below for additional information.
家庭的歪斜-t分布是学生的T系列的延伸，通过引进一个shape参数调节偏度，当shape=0，歪斜-t分布的降低通常的t分布。存在一个多元的分发版。下面的其他信息，请参阅参考。
参考文献----------References----------
Azzalini, A. and Capitanio, A. (2003). Distributions generated by perturbation of symmetry with emphasis on a multivariate skew t distribution. J.Roy. Statist. Soc. B 65, 367–389.
参见----------See Also----------
st.mle, sn.2logL.profile
st.mle，sn.2logL.profile
实例----------Examples----------
data(ais, package="sn")
attach(ais)
a <- st.2logL.profile(y=bmi, xlab="alpha", ylab="log(df)")
a <- st.2logL.profile(y=bmi, fixed.comp=4, fixed.values=log(c(1,25)))
a <- st.2logL.profile(X=cbind(1,lbm), y=bmi, fixed.comp=5,
fixed.values=log(c(5,25)), xlab="log(df)", npts=50)
a <- st.2logL.profile(X=cbind(1,Ht), y=Wt, fixed.comp=c(4,5),
fixed.values=cbind(c(-1,5), log(c(2,25))),
xlab="alpha", ylab="log(df)")
转载请注明:出自 生物统计家园网(http://www.biostatistic.net)。
注：
注1：为了方便大家学习，本文档为生物统计家园网机器人LoveR翻译而成，仅供个人R语言学习参考使用，生物统计家园保留版权。
注2：由于是机器人自动翻译，难免有不准确之处，使用时仔细对照中、英文内容进行反复理解，可以帮助R语言的学习。
注3：如遇到不准确之处，请在本贴的后面进行回帖，我们会逐渐进行修订。
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发表于 2012-9-30 11:20:38
