Result of a Cholesky decomposition with the NgPeyton
method
Objects from the Class
Objects are created by calls of the form chol(x,method="NgPeyton", ...)
and should not be created directly with a
new("spam.chol.NgPeyton", ...) call.
At present, no proper print method is defined. However, the factor can
be transformed into a spam object.
Methods
as.matrix
signature(x = "spam.chol.NgPeyton"): Transform the factor
into a regular matrix.
as.spam
signature(x = "spam.chol.NgPeyton"): Transform the factor
into a spam object.
backsolve
signature(r = "spam.chol.NgPeyton"): solving
a triangular system, see solve.
forwardsolve
signature(l = "spam.chol.NgPeyton"): solving
a triangular system, see solve.
c
signature(x = "spam.chol.NgPeyton"): Coerce the factor into a vector.
determinant
signature(x = "spam.chol.NgPeyton"):
Calculates the determinant from the factor, see also det.
diag
signature(x = "spam.chol.NgPeyton"): Extracts the
diagonal entries.
dim
signature(x = "spam.chol.NgPeyton"): Retrieve the
dimension. Note that "dim<-" is not implemented.
display
signature(x = "spam.chol.NgPeyton"): Transformation
to a spam object and display, see also display.
image
signature(x = "spam.chol.NgPeyton"): Transformation
to a spam object and display, see also image.
length
signature(x = "spam.chol.NgPeyton"): Retrieve the
dimension. Note that "length<-" is not implemented.
ordering
signature(x = "spam.chol.NgPeyton"):
Retrieves the ordering, in ordering.
print
signature(x = "spam.chol.NgPeyton"): Short description.
show
signature(object = "spam.chol.NgPeyton"): Short description.
summary
signature(object = "spam.chol.NgPeyton"):
Description of the factor, returns (as a list) nnzR, nnzcolindices,
the density of the factor density, and fill-in ratio
fillin. For the use of the first two, see ‘Examples’
in chol.
t
signature(x = "spam.chol.NgPeyton"): Transformation
to a spam object and transposition.
chol
signature(x = "spam.chol.NgPeyton"): Returns
x unchanged.
Author(s)
Reinhard Furrer
References
Ng, E. G. and B. W. Peyton (1993), "Block sparse Cholesky algorithms
on advanced uniprocessor computers", SIAM J. Sci. Comput., 14,
pp. 1034-1056.
See Also
print.spamordering and chol
Examples
x <- spam( c(4,3,0,3,5,1,0,1,4),3)
cf <- chol( x)
cf
as.spam( cf)
# Modify at own risk...
slotNames(cf)