SFBM-class: Class SFBM

SFBM-classR Documentation

Class SFBM


A reference class for storing and accessing sparse matrix-like data stored in files on disk.

Convert a 'dgCMatrix' or 'dsCMatrix' to an SFBM.


as_SFBM(spmat, backingfile = tempfile(), compact = FALSE)



A 'dgCMatrix' (non-symmetric sparse matrix of type 'double') or 'dsCMatrix' (symmetric sparse matrix of type 'double').


Path to file where to store data. Extension .sbk is automatically added.


Whether to use a compact format? Default is FALSE. This is useful when non-zero values in columns are contiguous (or almost).


An object of class SFBM has many fields:

  • $address: address of the external pointer containing the underlying C++ object to be used as a XPtr<SFBM> in C++ code

  • $extptr: (internal) use $address instead

  • $nrow: number of rows

  • $ncol: number of columns

  • $nval: number of non-zero values

  • $p: vector of column positions

  • $backingfile or $sbk: File with extension 'sbk' that stores the data of the SFBM

  • $rds: 'rds' file (that may not exist) corresponding to the 'sbk' file

  • $is_saved: whether this object is stored in $rds?

And some methods:

  • $save(): Save the SFBM object in $rds. Returns the SFBM.

  • $add_columns(): Add new columns from a 'dgCMatrix' or a 'dsCMatrix'.


The new SFBM.


spmat2 <- Matrix::Diagonal(4, 0:3)
spmat2[4, 2] <- 5
spmat2[1, 4] <- 6
spmat2[3, 4] <- 7

# Stores all (i, x) for x != 0
(X2 <- as_SFBM(spmat2))
matrix(readBin(X2$sbk, what = double(), n = 100), 2)

# Stores only x, but all (even the zero ones) from first to last being not 0
(X3 <- as_SFBM(spmat2, compact = TRUE))
readBin(X3$sbk, what = double(), n = 100)

bigsparser documentation built on June 7, 2022, 9:06 a.m.