mle.tmvnorm(tmvtnorm)
mle.tmvnorm()所属R语言包:tmvtnorm
Maximum Likelihood Estimation for the Truncated Multivariate Normal Distribution
对于截断多元正态分布的最大似然估计
译者:生物统计家园网 机器人LoveR
描述----------Description----------
Maximum Likelihood Estimation for the Truncated Multivariate Normal Distribution
对于截断多元正态分布的最大似然估计
用法----------Usage----------
mle.tmvnorm(X,
lower = rep(-Inf, length = ncol(X)),
upper = rep(+Inf, length = ncol(X)),
start = list(mu = rep(0, ncol(X)), sigma = diag(ncol(X))),
fixed = list(), method = "BFGS",
cholesky = FALSE,
lower.bounds = -Inf,
upper.bounds = +Inf,
...)
参数----------Arguments----------
参数:X
Matrix of quantiles, each row is taken to be a quantile.
矩阵位数,每一行是一个位数。
参数:lower
Vector of lower truncation points, default is rep(-Inf, length = ncol(X)).
矢量较低的截断点,默认是rep(-Inf, length = ncol(X))。
参数:upper
Vector of upper truncation points, default is rep( Inf, length = ncol(X)).
向量上的截断点,默认是rep( Inf, length = ncol(X))。
参数:start
Named list with elements mu (mean vector) and sigma (covariance matrix). Initial values for optimizer.
名为List的元素mu(均值向量)和sigma(协方差矩阵)。优化的初始值。
参数:fixed
Named list. Parameter values to keep fixed during optimization.
命名列表。在优化过程中的参数值保持固定。
参数:method
Optimization method to use. See optim
优化的方法来使用。见optim
参数:cholesky
if TRUE, we use the Cholesky decomposition of sigma as parametrization
如果是TRUE,我们使用Cholesky分解sigma的参数化
参数:lower.bounds
lower bounds/box constraints for method "L-BFGS-B"
的下限/箱的限制法“L-BFGS-B”
参数:upper.bounds
upper bounds/box constraints for method "L-BFGS-B"
的上限/箱的限制法“L-BFGS-B”
参数:...
Further arguments to pass to optim
到传递optim的进一步的论据
Details
详细信息----------Details----------
This method performs a maximum likelihood estimation of the parameters mean and sigma of a truncated multinormal distribution, when the truncation points lower and upper are known. mle.tmvnorm() is a wrapper for the general maximum likelihood method mle, so one does not have to specify the negative log-likelihood function.
此方法执行mean和sigma的截断multinormal分布,截断点时,lower和upper被称为最大似然估计的参数。 mle.tmvnorm()是一个包装的最大似然法mle,所以人们并不需要指定的负对数似然函数。
The log-likelihood function for a data matrix X (T x n) can be established straightforward as
对数似然函数可以建立简单的数据矩阵X(T XN)
As mle, this method returns an object of class mle, for which various diagnostic methods are available, like profile(), confint() etc. See examples.
mle,此方法返回一个类的对象mle,为各种诊断方法,如profile(),confint()等查看的例子。
In order to adapt the estimation problem to mle, the named parameters for mean vector elements are "mu_i" and the elements of the covariance matrix are "sigma_ij" for the lower triangular matrix elements, i.e. (j <= i).
为了适应估计问题mle,命名参数的均值向量元素是“mu_i”和协方差矩阵的元素是“sigma_ij”为下三角矩阵元素,即(十< = i)条。
值----------Value----------
An object of class mle-class
对象的类mle-class
(作者)----------Author(s)----------
Stefan Wilhelm <a href="mailto:wilhelm@financial.com">wilhelm@financial.com</a>
参见----------See Also----------
mle and mle-class
mle和mle-class
实例----------Examples----------
## Not run: [#不运行:]
set.seed(1.2345)
# the actual parameters[实际参数]
lower <- c(-1,-1)
upper <- c(1, 2)
mu <- c(0, 0)
sigma <- matrix(c(1, 0.7,
0.7, 2), 2, 2)
# generate random samples [产生随机样本]
X <- rtmvnorm(n=500, mu, sigma, lower, upper)
method <- "BFGS"
# estimate mean vector and covariance matrix sigma from random samples X[估计从随机样本平均向量和协方差矩阵西格玛所述]
# with default start values[使用默认的启动值]
mle.fit1 <- mle.tmvnorm(X, lower=lower, upper=upper)
# diagnostic output of the estimated parameters[估计参数的诊断输出]
summary(mle.fit1)
logLik(mle.fit1)
vcov(mle.fit1)
# profiling the log likelihood and confidence intervals[分析对数似然置信区间]
mle.profile1 <- profile(mle.fit1, X, method="BFGS", trace=TRUE)
confint(mle.profile1)
par(mfrow=c(3,2))
plot(mle.profile1)
# choosing a different start value[选择不同的初始值]
mle.fit2 <- mle.tmvnorm(X, lower=lower, upper=upper,
start=list(mu=c(0.1, 0.1),
sigma=matrix(c(1, 0.4, 0.4, 1.8),2,2)))
summary(mle.fit2)
## End(Not run)[#(不执行)]
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注:
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