Construct a sparse banded matrix by specifying its non-zero sup- and super-diagonals.
bandSparse(n, m = n, k, diagonals, symmetric = FALSE,
repr = "C", giveCsparse = (repr == "C"))
the matrix dimension \((n,m) = (nrow, ncol)\).
integer vector of “diagonal numbers”, with identical
meaning as in band(*, k)
, i.e., relative to the main diagonal,
which is k=0
.
optional list of sub-/super- diagonals; if missing,
the result will be a pattern matrix, i.e., inheriting from
class '>nMatrix
.
diagonals
can also be \(n' \times d\) matrix, where
d <- length(k)
and \(n' >= min(n,m)\). In that case,
the sub-/super- diagonals are taken from the columns of
diagonals
, where only the first several rows will be used
(typically) for off-diagonals.
character
string, one of "C"
,
"T"
, or "R"
, specifying the sparse representation to
be used for the result, i.e., one from the super classes
'>CsparseMatrix
, '>TsparseMatrix
, or
'>RsparseMatrix
.
a sparse matrix (of class
'>CsparseMatrix
) of dimension \(n \times m\)
with diagonal “bands” as specified.
band
, for extraction of matrix bands;
bdiag
, diag
,
sparseMatrix
,
Matrix
.
# NOT RUN { diags <- list(1:30, 10*(1:20), 100*(1:20)) s1 <- bandSparse(13, k = -c(0:2, 6), diag = c(diags, diags[2]), symm=TRUE) s1 s2 <- bandSparse(13, k = c(0:2, 6), diag = c(diags, diags[2]), symm=TRUE) stopifnot(identical(s1, t(s2)), is(s1,"dsCMatrix")) ## a pattern Matrix of *full* (sub-)diagonals: bk <- c(0:4, 7,9) (s3 <- bandSparse(30, k = bk, symm = TRUE)) ## If you want a pattern matrix, but with "sparse"-diagonals, ## you currently need to go via logical sparse: lLis <- lapply(list(rpois(20, 2), rpois(20,1), rpois(20,3))[c(1:3,2:3,3:2)], as.logical) (s4 <- bandSparse(20, k = bk, symm = TRUE, diag = lLis)) (s4. <- as(drop0(s4), "nsparseMatrix")) n <- 1e4 bk <- c(0:5, 7,11) bMat <- matrix(1:8, n, 8, byrow=TRUE) bLis <- as.data.frame(bMat) B <- bandSparse(n, k = bk, diag = bLis) Bs <- bandSparse(n, k = bk, diag = bLis, symmetric=TRUE) B [1:15, 1:30] Bs[1:15, 1:30] ## can use a list *or* a matrix for specifying the diagonals: stopifnot(identical(B, bandSparse(n, k = bk, diag = bMat)), identical(Bs, bandSparse(n, k = bk, diag = bMat, symmetric=TRUE)) , inherits(B, "dtCMatrix") # triangular! ) # }
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