Read matrices stored in the Harwell-Boeing or MatrixMarket formats
sparseMatrix objects to one of these
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a real sparse matrix
optional additional arguments. Currently none are used in any methods.
readMM functions return an object that
inherits from the
"Matrix" class. Methods for the
writeMM generic functions usually return
NULL and, as a side effect, the matrix
file in the MatrixMarket format (writeMM).
The Harwell-Boeing format is older and less flexible than the
MatrixMarket format. The function
writeHB was deprecated and
has now been removed. Please use
A very simple way to export small sparse matrices
S, is to use
summary(S) which returns a
j, and possibly
sparseMatrix-class, and an example below.
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str(pores <- readMM(system.file("external/pores_1.mtx", package = "Matrix"))) str(utm <- readHB(system.file("external/utm300.rua", package = "Matrix"))) str(lundA <- readMM(system.file("external/lund_a.mtx", package = "Matrix"))) str(lundA <- readHB(system.file("external/lund_a.rsa", package = "Matrix"))) ## Not run: ## NOTE: The following examples take quite some time ## ---- even on a fast internet connection: if(FALSE) # the URL has been corrected, but we need an un-tar step! str(sm <- readHB(gzcon(url("http://www.cise.ufl.edu/research/sparse/RB/Boeing/msc00726.tar.gz")))) str(jgl009 <- readMM(gzcon(url("ftp://math.nist.gov/pub/MatrixMarket2/Harwell-Boeing/counterx/jgl009.mtx.gz")))) ## End(Not run) data(KNex) writeMM(KNex$mm, "mmMM.mtx") ## very simple export - in triplet format - to text file: data(CAex) s.CA <- summary(CAex) s.CA # shows (i, j, x) [columns of a data frame] message("writing to ", outf <- tempfile()) write.table(s.CA, file = outf, row.names=FALSE) ## and read it back -- showing off sparseMatrix(): str(dd <- read.table(outf, header=TRUE)) ## has columns (i, j, x) -> we can use via do.call() as arguments to sparseMatrix(): mm <- do.call(sparseMatrix, dd) stopifnot(all.equal(mm, CAex, tolerance=1e-15))
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