Formatting Sparse Numeric Matrices Utilities

Utilities for formatting sparse numeric matrices in a flexible way. These functions are used by the format and print methods for sparse matrices and can be applied as well to standard R matrices. Note that all arguments but the first are optional.

formatSparseM() is the main “workhorse” of formatSpMatrix, the format method for sparse matrices.

.formatSparseSimple() is a simple helper function, also dealing with (short/empty) column names construction.

Usage

formatSparseM(x, zero.print = ".", align = c("fancy", "right"),
              m = as(x,"matrix"), asLogical=NULL, uniDiag=NULL,
              digits=NULL, cx, iN0, dn = dimnames(m))

.formatSparseSimple(m, asLogical=FALSE, digits=NULL,
        col.names, note.dropping.colnames = TRUE,
                    dn=dimnames(m))

Arguments

x: an R object inheriting from class sparseMatrix.
zero.print: character which should be used for structural zeroes. The default "." may occasionally be replaced by " " (blank); using "0" would look almost like print()ing of non-sparse matrices.
align: a string specifying how the zero.print codes should be aligned, see formatSpMatrix.
m: (optional) a (standard R) matrix version of x.
asLogical: should the matrix be formatted as a logical matrix (or rather as a numeric one); mostly for formatSparseM().
uniDiag: logical indicating if the diagonal entries of a sparse unit triangular or unit-diagonal matrix should be formatted as "I" instead of "1" (to emphasize that the 1's are “structural”).
digits: significant digits to use for printing, see print.default.
cx: (optional) character matrix; a formatted version of x, still with strings such as "0.00" for the zeros.
iN0: (optional) integer vector, specifying the location of the non-zeroes of x.
col.names, note.dropping.colnames: see formatSpMatrix.
dn: dimnames to be used; a list (of length two) with row and column names (or NULL).

Value

a character matrix like cx, where the zeros have been replaced with (padded versions of) zero.print. As this is a dense matrix, do not use these functions for really large (really) sparse matrices!

Author

Martin Maechler

Examples

m <- suppressWarnings(matrix(c(0, 3.2, 0,0, 11,0,0,0,0,-7,0), 4,9))
fm <- formatSparseM(m)
noquote(fm)
#>                                     
#> [1,] .   11 .   3.2 . -7.0 .  .  .  
#> [2,] 3.2 .  -7 .    . .    .  .  .  
#> [3,] .   .  .  .    . .    11 .  3.2
#> [4,] .   .  .  11.0 .  3.2 .  -7 .  
## nice, but this is nicer {with "units" vertically aligned}:
print(fm, quote=FALSE, right=TRUE)
#>                                     
#> [1,] .   11  .  3.2 . -7.0  .  . .  
#> [2,] 3.2  . -7  .   .  .    .  . .  
#> [3,] .    .  .  .   .  .   11  . 3.2
#> [4,] .    .  . 11.0 .  3.2  . -7 .  
## and "the same" as :
Matrix(m)
#> 4 x 9 sparse Matrix of class "dgCMatrix"
#>                                     
#> [1,] .   11  .  3.2 . -7.0  .  . .  
#> [2,] 3.2  . -7  .   .  .    .  . .  
#> [3,] .    .  .  .   .  .   11  . 3.2
#> [4,] .    .  . 11.0 .  3.2  . -7 .  

## align = "right" is cheaper -->  the "." are not aligned:
noquote(f2 <- formatSparseM(m,align="r"))
#>                                     
#> [1,] .   11 .   3.2 . -7.0 .  .  .  
#> [2,] 3.2 .  -7 .    . .    .  .  .  
#> [3,] .   .  .  .    . .    11 .  3.2
#> [4,] .   .  .  11.0 .  3.2 .  -7 .  
stopifnot(f2 == fm   |   m == 0, dim(f2) == dim(m),
         (f2 == ".") == (m == 0))