Pia 发表于 2013-1-15 07:27 
老师,我已经弄清楚了之前问题所在了,我想请问一下,dcc.estimation中dcc.para是怎么确定的呢?
ini.dcc=dcc.para,
ini.dcc : a vector of initial values for the DCC parameters (2 x 1)
dcc.para 就是initial values
设定好适当值,其接果是相近的
如底下:dcc.para <- c(0.01,0.98)
dcc.para1 <- c(0.02,0.95)
dcc.para2 <- c(0.02,0.9)
####
library(ccgarch)
set.seed(123)
nobs <- 1000; cut <- 1000
a <- c(0.003, 0.005)
A <- diag(c(0.2,0.15))
B <- diag(c(0.75, 0.8))
uncR <- matrix(c(1.0, 0.4, 0.4, 1.0),2,2)
dcc.para <- c(0.01,0.98)
dcc.data <- dcc.sim(nobs, a, A, B, uncR, dcc.para, model="diagonal")
# Estimating a DCC-GARCH(1,1) model
dcc.para1 <- c(0.02,0.95)
dcc.para2 <- c(0.02,0.9)
dcc.results <- dcc.estimation(inia=a, iniA=A, iniB=B, ini.dcc=dcc.para,dvar=dcc.data$eps, model="diagonal")
dcc.results1 <- dcc.estimation(inia=a, iniA=A, iniB=B, ini.dcc=dcc.para1,dvar=dcc.data$eps, model="diagonal")
dcc.results2 <- dcc.estimation(inia=a, iniA=A, iniB=B, ini.dcc=dcc.para2,dvar=dcc.data$eps, model="diagonal")
# Parameter estimates and their robust standard errors
dcc.results$out
# a1 a2 A11 A22 B11 B22 dcc alpha dcc beta
#estimates 0.0020597062 0.00332611 0.19605728 0.190663641 0.77793259 0.78573525 0.006854594 0.98452082
#std.err 0.0007481721 0.03895612 0.04131927 0.001078035 0.02904991 0.03088621 0.006908613 0.02031203
dcc.results1$out
# a1 a2 A11 A22 B11 B22 dcc alpha dcc beta
#estimates 0.0020597062 0.00332611 0.19605728 0.190663641 0.77793259 0.78573525 0.006856761 0.98453281
#std.err 0.0007481721 0.03895612 0.04131927 0.001078035 0.02904991 0.03088621 0.006904375 0.02027669
dcc.results2$out
# a1 a2 A11 A22 B11 B22 dcc alpha dcc beta
#estimates 0.0020597062 0.00332611 0.19605728 0.190663641 0.77793259 0.78573525 0.006872483 0.98447394
#std.err 0.0007481721 0.03895612 0.04131927 0.001078035 0.02904991 0.03088621 0.006925764 0.02037307