dCholCMatrix-class {Matrix} | R Documentation |
"dCholCMatrix"
is class of Cholesky decompositions
of symmetric, sparse, compressed, column-oriented matrices (the
"dsCMatrix"
class). "lCholCMatrix"
is class showing the
logical structure (positions of the non-zeros) of these Cholesky decompositions.
Objects can be created by calls of the form new("dCholCMatrix", ...)
but are more commonly created from chol
applied to
dsCMatrix
or lsCMatrix
objects.
perm
:"integer"
giving the
permutation of the rows and columns chosen to minimize fill-in.
If pivoting has not been applied this will be an integer vector of
length 0.diag
:"dtCMatrix"
class. It is always "N"
for this class.uplo
:"U"
or "u"
) or the lower triangle
("L"
or "l"
) is stored. At present only the lower
triangle form is allowed.p
:"integer"
of pointers, one
for each column, to the initial (zero-based) index of elements in
the column.i
:"integer"
of length nnzero
(number of non-zero elements). These are the row numbers for
each non-zero element in the matrix.x
:"numeric"
- the non-zero
elements of the matrix. Present only in the "dCholCMatrix"
class.factors
:"list"
- a list
of factorizations of the matrix. Dim
:"integer"
- the dimensions
of the matrix - must be an integer vector with exactly two
non-negative values.Dimnames
:"Matrix"
class, see Matrix
.D
:"numeric"
- the diagonal
elements of the matrix D in the LDL' decomposition. Present only
in the "dCholCMatrix"
class.Parent
:"integer"
- the
elimination tree of the (possibly permuted) symmetric matrix.
Class "dtCMatrix"
, directly.
Class "dgCMatrix"
, by class "dtCMatrix"
.
No methods defined with class "dCholCMatrix" in the signature.
Class dgCMatrix
data(KNex) xpx <- with(KNex, crossprod(mm)) str(xpx) str(ch <- chol(xpx)) ## Visualize the sparseness: dq <- function(ch) paste('"',ch,'"', sep="") ## dQuote(<UTF-8>) gives bad plots image(xpx, main=paste("crossprod(mm) : Sparse", dq(class(xpx)))) image(ch, main= paste("chol (crossprod(mm)) : Sparse", dq(class(ch))))