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Plot of bivariate skew-\eqn{t} density function
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Produces a contour plot of the density function of a bivariate
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\usage{dst2.plot(x, y, xi, Omega, alpha, df, dp = NULL, ...) }
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vector of values of the first component.
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vector of values of the second component.
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a vector of length 2 containing the location parameter.
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a 2 by 2 matrix containing a covariance matrix.
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a vector of length 2 containing the shape parameter.
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a positive number, representing the degrees of freedom .
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a list with components named \code{xi, Omega, alpha, df}, containing
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quantities as described above. If this parameter is set, then the
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individual parameters must not be.
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additional parameters to be passed to \code{contour}.
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A list containing the original input parameters plus a matrix
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containing the density function evaluated at the grid formed
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by the \code{x} and \code{y} values.
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\details{Typical usages are
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dst2.plot(x, y, xi, Omega, alpha, df, ...)
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dst2.plot(x, y, dp=, ...)
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The density function is evalutate at the grid of points whose
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coordinates are given by vectors \code{x} and \code{y}.
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The actual computation is done by the function \code{dmst}.
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A contour level plot is produced on the graphical window.
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The family of multivariate skew-t distributions is an extension of the
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multivariate Student's \eqn{t} family, via the introduction of a \code{shape}
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parameter which regulates skewness; when \code{shape=0}, the skew-\eqn{t}
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distribution reduces to the usual \eqn{t} distribution.
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When \code{df=Inf} the distribution reduces to the multivariate skew-normal
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one; see \code{dmsn}. See the reference below for additional information.
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Azzalini, A. and Capitanio, A. (2003).
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Distributions generated by perturbation of symmetry
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with emphasis on a multivariate skew \eqn{t} distribution.
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\emph{J.Roy. Statist. Soc. B} \bold{65}, 367--389.
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\code{\link{dmst}}, \code{\link{dsn2.plot}}
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x <- y <- seq(-5, 5, length=35)
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dst2.plot(x, y, c(-1,2), diag(c(1,2.5)), c(2,-3), df=5)
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\keyword{distribution}
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man/dst2.plot.Rd
