CHMfactor-class {Matrix} | R Documentation |
The virtual class "CHMfactor"
is a class of
CHOLMOD-based Cholesky factorizations of symmetric, sparse,
compressed, column-oriented matrices. Such a factorization is
simplicial (virtual class "CHMsimpl"
) or supernodal (virtual
class "CHMsuper"
). Objects that inherit from these classes are
either numeric factorizations (classes "dCHMsimpl"
and
"dCHMsuper"
) or symbolic factorizations (classes
"nCHMsimpl"
and "nCHMsuper"
).
Objects can be created by calls of the form new("dCHMsuper", ...)
but are more commonly created via Cholesky()
.
applied to dsCMatrix
or
lsCMatrix
objects.
of "CHMfactor"
and all classes inheriting from it:
perm
:colcount
:"integer"
.... type
:"integer"
.... Slots of the non virtual classes “[dl]CHM(super|simpl)”:
p
:"integer"
of pointers, one
for each column, to the initial (zero-based) index of elements in
the column. Only present in classes that contain "CHMsimpl"
.i
:"integer"
of length nnzero
(number of non-zero elements). These are the row numbers for
each non-zero element in the matrix. Only present in classes that
contain "CHMsimpl"
.x
:"d*"
classes: "numeric"
- the
non-zero elements of the matrix.signature(from = "CHMfactor", to = "sparseMatrix")
signature(x = "CHMfactor")
signature(a = "CHMfactor", b = "ddenseMatrix")
The solve
methods for a "CHMfactor"
object take an
optional third argument system
whose value can be one of the
character strings "A"
, "LDLt"
, "LD"
,
"DLt"
, "L"
, "Lt"
, "D"
, "P"
or
"Pt"
. This argument describes the system to be solved. The
default is to solve Ax = b
for x
where A
is
sparse, positive-definite matrix that was factored to produce
"a"
.signature(a = "CHMfactor", b = "dsparseMatrix")
signature(a = "CHMfactor", b = "matrix")
Cholesky
, also for examples;
class dgCMatrix
.