gmm.tmvnorm(tmvtnorm)
gmm.tmvnorm()所属R语言包:tmvtnorm
GMM Estimation for the Truncated Multivariate Normal Distribution
GMM估计截断多元正态分布
译者:生物统计家园网 机器人LoveR
描述----------Description----------
Generalized Method of Moments (GMM) Estimation for the Truncated Multivariate Normal Distribution
广义矩方法(GMM)估计截断的多元正态分布
用法----------Usage----------
gmm.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=c("ManjunathWilhelm","Lee"),
cholesky = FALSE,
...)
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
Which set of moment conditions used, possible methods are "ManjunathWilhelm" (default) and "Lee".
哪一组用矩条件,可行的方法是“ManjunathWilhelm”(默认)和“利”。
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:...
Further arguments to pass to gmm
到传递gmm的进一步的论据
Details
详细信息----------Details----------
This method performs an estimation of the parameters mean and sigma of a truncated multinormal distribution using the Generalized Method of Moments (GMM), when the truncation points lower and upper are known. gmm.tmvnorm() is a wrapper for the general GMM method gmm, so one does not have to specify the moment conditions.
此方法执行的参数估计mean和sigma使用广义矩方法(GMM),截断点时,截断multinormal分布lower和upper众所周知的。 gmm.tmvnorm()是一个包装的一般GMM方法gmm,所以人们并不需要指定的那一刻。
Manjunath/Wilhelm moment conditions<br> Because the first and second moments can be computed thanks to the mtmvnorm function, we can set up a method-of-moments estimator by equating the sample moments to their population counterparts. This way we have an exactly identified case.
曼朱纳特/威廉·时刻条件<BR>的,因为第一和第二的时刻,可以计算mtmvnorm功能,我们可以设置的方法,矩估计,样本矩,他们的人口相等。通过这种方式,我们有一个完全确定的情况下。
Lee (1979,1983) moment conditions<br> The recursive moment conditions presented by Lee (1979,1983) are defined for l=0,1,2,… as
李(1979,1983)时刻条件<BR>的递归时刻李(1979,1983)提出的条件被定义为l=0,1,2,…
where E(x_i^l) and E(x_i^l \textbf{x}) are the moments of x_i^l and x_i^l \textbf{x} respectively and F_i(c)/F is the one-dimensional marginal density in variable i as calculated by dtmvnorm.marginal. σ^{iT} is the i-th column of the inverse covariance matrix Σ^{-1}.
E(x_i^l)和E(x_i^l \textbf{x})是x_i^l和x_i^l \textbf{x}分别的时刻F_i(c)/F是一维的边缘密度变量i计算dtmvnorm.marginal。 σ^{iT}是i个列的协方差矩阵的逆Σ^{-1}。
This method returns an object of class gmm, for which various diagnostic methods are available, like profile(), confint() etc. See examples.
此方法返回一个对象的类gmm,为各种诊断方法,如profile(),confint()等,请参阅例子。
值----------Value----------
An object of class gmm
对象的类gmm
(作者)----------Author(s)----------
Stefan Wilhelm <a href="mailto:wilhelm@financial.com">wilhelm@financial.com</a>
参考文献----------References----------
Journal of the Royal Statistical Society, Series B, 23, 223–229
Economics Letters, 3, 165–169
Economics Letters, 11, 245–250
Working Paper. Available at SSRN: http://ssrn.com/abstract=1472153
参见----------See Also----------
gmm
gmm
实例----------Examples----------
set.seed(1.234)
# the actual parameters[实际参数]
lower <- c(-1, -2)
upper <- c(3, Inf)
mu <- c(0, 0)
sigma <- matrix(c(1, 0.8,
0.8, 2), 2, 2)
# generate random samples [产生随机样本]
X <- rtmvnorm(n=500, mu, sigma, lower, upper)
# 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]
gmm.fit1 <- gmm.tmvnorm(X, lower=lower, upper=upper)
# diagnostic output of the estimated parameters[估计参数的诊断输出]
summary(gmm.fit1)
vcov(gmm.fit1)
# confidence intervals[置信区间]
confint(gmm.fit1)
# choosing a different start value[选择不同的初始值]
gmm.fit2 <- gmm.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(gmm.fit2)
# GMM estimation with Lee (1983) moment conditions[GMM估计与李(1983)矩条件]
gmm.fit3 <- gmm.tmvnorm(X, lower=lower, upper=upper, method="Lee")
summary(gmm.fit3)
confint(gmm.fit3)
# MLE estimation for comparison[最大似然估计进行比较]
mle.fit1 <- mle.tmvnorm(X, lower=lower, upper=upper)
confint(mle.fit1)
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注:
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