Displaying 2 results from an estimated 2 matches for "garch_norm".
2006 Nov 22
2
problems with garchFit
...means no skewness (I can
not find the paper defining the distribution).
library(fSeries)
curve(dsnorm(x, 0, 1, 1), -2, 2, add = F, col = 'red') #skew normal with
skew 1
curve(dnorm(x, 0, 1), -2, 2, add = T, col = 'blue') #normal
Then I try them as innovations,
#normal innovation
garch_norm <- garchFit(series = logr, include.mean = F)
#skew normal innovation
#this line do not include skew, so it got same result as normal
garch_snorm <- garchFit(series = logr, cond.dist = 'dsnorm', include.mean =
F, include.skew = F)
#this line includes skew, but use default skew = 1,...
2006 Nov 22
0
questions about garchFit
...m_fit <- snormFit(logr)
curve(dsnorm(x, snorm_fit$est[1], snorm_fit$est[2], snorm_fit$est[3]), -.25,
.15, add = TRUE, col=4)
st_fit <- sstdFit(logr)
curve(dsstd(x, st_fit$est[1], st_fit$est[2], st_fit$est[3], st_fit$est[4]),
-.25, .15, add = TRUE, col=3)
library(fSeries)
#normal innovation
garch_norm <- garchFit(series = logr, include.mean = F)
#t inovation
garch_t <- garchFit(series = logr, cond.dist = 'dstd', include.mean = F,
include.shape = T)
garch_t1 <- garchFit(series = logr, cond.dist = 'dstd', include.mean = F,
shape = t_fit$est[3], include.shape = T)
#skew n...