Package 'SparseArray'

Title: High-performance sparse data representation and manipulation in R
Description: The SparseArray package provides array-like containers for efficient in-memory representation of multidimensional sparse data in R (arrays and matrices). The package defines the SparseArray virtual class and two concrete subclasses: COO_SparseArray and SVT_SparseArray. Each subclass uses its own internal representation of the nonzero multidimensional data: the "COO layout" and the "SVT layout", respectively. SVT_SparseArray objects mimic as much as possible the behavior of ordinary matrix and array objects in base R. In particular, they suppport most of the "standard matrix and array API" defined in base R and in the matrixStats package from CRAN.
Authors: Hervé Pagès [aut, cre] , Vince Carey [fnd] , Rafael A. Irizarry [fnd] , Jacques Serizay [ctb]
Maintainer: Hervé Pagès <[email protected]>
License: Artistic-2.0
Version: 1.7.2
Built: 2024-11-15 03:34:43 UTC
Source: https://github.com/bioc/SparseArray

Help Index

COO_SparseArray objects

Description

The COO_SparseArray class is a container for efficient in-memory representation of multidimensional sparse arrays. It uses the COO layout to represent the nonzero data internally.

A COO_SparseMatrix object is a COO_SparseArray object of 2 dimensions.

IMPORTANT NOTE: COO_SparseArray and COO_SparseMatrix objects are now superseded by the new and more efficient SVT_SparseArray and SVT_SparseMatrix objects.

Usage

## Constructor function:
COO_SparseArray(dim, nzcoo=NULL, nzdata=NULL, dimnames=NULL, check=TRUE)

## Getters (in addition to dim(), length(), and dimnames()):
nzcoo(x)
nzdata(x)

Arguments

dim

The dimensions (supplied as an integer vector) of the COO_SparseArray or COO_SparseMatrix object to construct.

nzcoo

A matrix containing the array coordinates of the nonzero elements.

This must be an integer matrix of array coordinates like one returned by base::arrayInd or S4Arrays::Lindex2Mindex, that is, a matrix with length(dim) columns and where each row is an n-tuple representing the coordinates of an array element.

nzdata

A vector (atomic or list) of length nrow(nzcoo) containing the nonzero elements.

dimnames

The dimnames of the object to construct. Must be NULL or a list of length the number of dimensions. Each list element must be either NULL or a character vector along the corresponding dimension.

check

Should the object be validated upon construction?

x

A COO_SparseArray or COO_SparseMatrix object.

Value

  • For COO_SparseArray(): A COO_SparseArray or COO_SparseMatrix object.

  • For nzcoo(): A matrix with one column per dimension containing the array coordinates of the nonzero elements.

  • For nzdata(): A vector parallel to nzcoo(x) (i.e. with one element per row in nzcoo(x)) containing the nonzero elements.

See Also

  • The new SVT_SparseArray class for a replacement of of the COO_SparseArray class.

  • The SparseArray class for the virtual parent class of COO_SparseArray and SVT_SparseArray.

  • S4 classes dgCMatrix and lgCMatrix defined in the Matrix package, for the de facto standard of sparse matrix representations in the R ecosystem.

  • base::arrayInd in the base package.

  • S4Arrays::Lindex2Mindex in the S4Arrays package for an improved (faster) version of base::arrayInd.

  • Ordinary array objects in base R.

Examples

## ---------------------------------------------------------------------
## EXAMPLE 1
## ---------------------------------------------------------------------
dim1 <- 5:3
nzcoo1 <- Lindex2Mindex(sample(60, 8), 5:3)
nzdata1 <- 11.11 * seq_len(nrow(nzcoo1))
coo1 <- COO_SparseArray(dim1, nzcoo1, nzdata1)
coo1

nzcoo(coo1)
nzdata(coo1)
type(coo1)
sparsity(coo1)

as.array(coo1)  # back to a dense representation

#as.matrix(coo1)  # error!

## ---------------------------------------------------------------------
## EXAMPLE 2
## ---------------------------------------------------------------------
m2 <- matrix(c(5:-2, rep.int(c(0L, 99L), 11)), ncol=6)
coo2 <- as(m2, "COO_SparseArray")
class(coo2)
dim(coo2)
length(coo2)
nzcoo(coo2)
nzdata(coo2)
type(coo2)
sparsity(coo2)

stopifnot(identical(as.matrix(coo2), m2))

t(coo2)
stopifnot(identical(as.matrix(t(coo2)), t(as.matrix(coo2))))

## ---------------------------------------------------------------------
## COERCION FROM/TO dg[C|R]Matrix OR lg[C|R]Matrix OBJECTS
## ---------------------------------------------------------------------
## dg[C|R]Matrix and lg[C|R]Matrix objects are defined in the Matrix
## package.

## dgCMatrix/dgRMatrix:

M2C <- as(coo2, "dgCMatrix")
stopifnot(identical(M2C, as(m2, "dgCMatrix")))

coo2C <- as(M2C, "COO_SparseArray")
## 'coo2C' is the same as 'coo2' except that 'nzdata(coo2C)' has
## type "double" instead of "integer":
stopifnot(all.equal(coo2, coo2C))
typeof(nzdata(coo2C))  # double
typeof(nzdata(coo2))   # integer

M2R <- as(coo2, "dgRMatrix")
stopifnot(identical(M2R, as(m2, "dgRMatrix")))
coo2R <- as(M2R, "COO_SparseArray")
stopifnot(all.equal(as.matrix(coo2), as.matrix(coo2R)))

## lgCMatrix/lgRMatrix:

m3 <- m2 == 99  # logical matrix
coo3 <- as(m3, "COO_SparseArray")
class(coo3)
type(coo3)

M3C <- as(coo3, "lgCMatrix")
stopifnot(identical(M3C, as(m3, "lgCMatrix")))
coo3C <- as(M3C, "COO_SparseArray")
identical(as.matrix(coo3), as.matrix(coo3C))

M3R <- as(coo3, "lgRMatrix")
#stopifnot(identical(M3R, as(m3, "lgRMatrix")))
coo3R <- as(M3R, "COO_SparseArray")
identical(as.matrix(coo3), as.matrix(coo3R))

## ---------------------------------------------------------------------
## A BIG COO_SparseArray OBJECT
## ---------------------------------------------------------------------
nzcoo4 <- cbind(sample(25000, 600000, replace=TRUE),
                sample(195000, 600000, replace=TRUE))
nzdata4 <- runif(600000)
coo4 <- COO_SparseArray(c(25000, 195000), nzcoo4, nzdata4)
coo4
sparsity(coo4)

is_nonna() and the nna*() functions

Description

A set of functions for direct manipulation of the non-NA elements of an array-like object.

Usage

is_nonna(x)

nnacount(x)
nnawhich(x, arr.ind=FALSE)
nnavals(x)
nnavals(x) <- value

Arguments

x

Typically (but not necessarily) an array-like object that is non-NA sparse, like an NaArray object.

However, x can also be an ordinary matrix or array, or any matrix-like or array-like object.

arr.ind

If arr.ind=FALSE (the default), the indices of the non-NA array elements are returned in a numeric vector (a.k.a. L-index). Otherwise, they're returned in an ordinary matrix (a.k.a. M-index).

See ?Lindex in the S4Arrays package for more information about L-index and M-index, and how to convert from one to the other.

Note that using arr.ind=TRUE won't work if nnacount(x) is >= .Machine$integer.max (= 2^31), because, in that case, the returned M-index would need to be a matrix with more rows than what is supported by base R.

value

A vector, typically of length nnacount(x) (or 1) and type type(x).

Details

nnacount(x) and nnawhich(x) are equivalent to, but typically more efficient than, sum(is_nonna(x)) and which(is_nonna(x)), respectively.

nnavals(x) is equivalent to, but typically more efficient than, x[nnawhich(x)] (or x[is_nonna(x)]).

nnavals(x) <- value replaces the values of the non-NA array elements in x with the supplied values. It's equivalent to, but typically more efficient than, x[nnawhich(x)] <- value.

Note that nnavals(x) <- nnavals(x) is guaranteed to be a no-op.

Value

is_nonna(): An array-like object of type() "logical" and same dimensions as the input object.

nnacount(): The number of non-NA array elements in x.

nnawhich(): The indices of the non-NA array elements in x, either as an L-index (if arr.ind is FALSE) or as an M-index (if arr.ind is TRUE). Note that the indices are returned sorted in strictly ascending order.

nnavals(): A vector of the same type() as x and containing the values of the non-NA array elements in x. Note that the returned vector is guaranteed to be parallel to nnawhich(x).

See Also

  • is_nonzero for is_nonzero() and nz*() functions nzcount(), nzwhich(), etc...

  • NaArray objects.

  • Ordinary array objects in base R.

  • base::which in base R.

Examples

a <- array(NA_integer_, dim=c(5, 12, 2))
a[sample(length(a), 20)] <- (-9):10

is_nonna(a)

## Get the number of non-NA array elements in 'a':
nnacount(a)

## nnawhich() returns the indices of the non-NA array elements in 'a'.
## Either as a "L-index" i.e. an integer (or numeric) vector of
## length 'nnacount(a)' containing "linear indices":
nnaidx <- nnawhich(a)
length(nnaidx)
head(nnaidx)

## Or as an "M-index" i.e. an integer matrix with 'nnacount(a)' rows
## and one column per dimension where the rows represent "array indices"
## (a.k.a. "array coordinates"):
Mnnaidx <- nnawhich(a, arr.ind=TRUE)
dim(Mnnaidx)

## Each row in the matrix is an n-tuple representing the "array
## coordinates" of a non-NA element in 'a':
head(Mnnaidx)
tail(Mnnaidx)

## Extract the values of the non-NA array elements in 'a' and return
## them in a vector "parallel" to 'nnawhich(a)':
a_nnavals <- nnavals(a)  # equivalent to 'a[nnawhich(a)]'
length(a_nnavals)
head(a_nnavals)

nnavals(a) <- 10 ^ nnavals(a)
a

## Sanity checks:
stopifnot(
  identical(nnaidx, which(!is.na(a))),
  identical(Mnnaidx, which(!is.na(a), arr.ind=TRUE, useNames=FALSE)),
  identical(nnavals(a), a[nnaidx]),
  identical(nnavals(a), a[Mnnaidx]),
  identical(`nnavals<-`(a, nnavals(a)), a)
)

is_nonzero() and the nz*() functions

Description

A set of functions for direct manipulation of the nonzero elements of an array-like object.

Usage

is_nonzero(x)

nzcount(x)
nzwhich(x, arr.ind=FALSE)
nzvals(x)
nzvals(x) <- value

sparsity(x)

Arguments

x

Typically (but not necessarily) an array-like object that is sparse, like a SparseArray derivative, or a dg[C|R]Matrix or lg[C|R]Matrix object from the Matrix package.

However, x can also be an ordinary matrix or array, or any matrix-like or array-like object.

arr.ind

If arr.ind=FALSE (the default), the indices of the nonzero array elements are returned in a numeric vector (a.k.a. L-index). Otherwise, they're returned in an ordinary matrix (a.k.a. M-index).

See ?Lindex in the S4Arrays package for more information about L-index and M-index, and how to convert from one to the other.

Note that using arr.ind=TRUE won't work if nzcount(x) is >= .Machine$integer.max (= 2^31), because, in that case, the returned M-index would need to be a matrix with more rows than what is supported by base R.

value

A vector, typically of length nzcount(x) (or 1) and type type(x).

Details

nzcount(x) and nzwhich(x) are equivalent to, but typically more efficient than, sum(is_nonzero(x)) and which(is_nonzero(x)), respectively.

nzvals(x) is equivalent to, but typically more efficient than, x[nzwhich(x)] (or x[is_nonzero(x)]).

nzvals(x) <- value replaces the values of the nonzero array elements in x with the supplied values. It's equivalent to, but typically more efficient than, x[nzwhich(x)] <- value.

Note that nzvals(x) <- nzvals(x) is guaranteed to be a no-op.

Value

is_nonzero(): An array-like object of type() "logical" and same dimensions as the input object.

nzcount(): The number of nonzero array elements in x.

nzwhich(): The indices of the nonzero array elements in x, either as an L-index (if arr.ind is FALSE) or as an M-index (if arr.ind is TRUE). Note that the indices are returned sorted in strictly ascending order.

nzvals(): A vector of the same type() as x and containing the values of the nonzero array elements in x. Note that the returned vector is guaranteed to be parallel to nzwhich(x).

sparsity(x): The ratio between the number of zero-valued elements in array-like object x and its total number of elements (length(x) or prod(dim(x))). More precisely, sparsity(x) is 1 - nzcount(x)/length(x).

See Also

Examples

a <- array(rpois(120, lambda=0.3), dim=c(5, 12, 2))

is_nonzero(a)

## Get the number of nonzero array elements in 'a':
nzcount(a)

## nzwhich() returns the indices of the nonzero array elements in 'a'.
## Either as a "L-index" i.e. an integer (or numeric) vector of
## length 'nzcount(a)' containing "linear indices":
nzidx <- nzwhich(a)
length(nzidx)
head(nzidx)

## Or as an "M-index" i.e. an integer matrix with 'nzcount(a)' rows
## and one column per dimension where the rows represent "array indices"
## (a.k.a. "array coordinates"):
Mnzidx <- nzwhich(a, arr.ind=TRUE)
dim(Mnzidx)

## Each row in the matrix is an n-tuple representing the "array
## coordinates" of a nonzero element in 'a':
head(Mnzidx)
tail(Mnzidx)

## Extract the values of the nonzero array elements in 'a' and return
## them in a vector "parallel" to 'nzwhich(a)':
a_nzvals <- nzvals(a)  # equivalent to 'a[nzwhich(a)]'
length(a_nzvals)
head(a_nzvals)

nzvals(a) <- log1p(nzvals(a))
a

## Sanity checks:
stopifnot(
  identical(nzidx, which(a != 0)),
  identical(Mnzidx, which(a != 0, arr.ind=TRUE, useNames=FALSE)),
  identical(nzvals(a), a[nzidx]),
  identical(nzvals(a), a[Mnzidx]),
  identical(`nzvals<-`(a, nzvals(a)), a)
)

NaArray objects

Description

EXPERIMENTAL!!!

Like SVT_SparseArray objects but the background value is NA instead of zero.

Usage

## Constructor function:
NaArray(x, dim=NULL, dimnames=NULL, type=NA)

Arguments

x

If dim is NULL (the default) then x must be an ordinary matrix or array, or a dgCMatrix/lgCMatrix object, or any matrix-like or array-like object that supports coercion to NaArray.

If dim is provided then x can either be missing, a vector (atomic or list), or an array-like object. If missing, then an all-NA NaArray object will be constructed. Otherwise x will be used to fill the returned object (length(x) must be <= prod(dim)). Note that if x is an array-like object then its dimensions are ignored i.e. it's treated as a vector.

dim

NULL or the dimensions (supplied as an integer vector) of the NaArray or NaMatrix object to construct. If NULL (the default) then the returned object will have the dimensions of matrix-like or array-like object x.

dimnames

The dimnames of the object to construct. Must be NULL or a list of length the number of dimensions. Each list element must be either NULL or a character vector along the corresponding dimension. If both dim and dimnames are NULL (the default) then the returned object will have the dimnames of matrix-like or array-like object x.

type

A single string specifying the requested type of the object.

By default the NaArray object returned by the constructor function will have the same type() as x. However the user can use the type argument to request a different type. Note that doing: 

    naa <- NaArray(x, type=type)

is equivalent to doing: 

    naa <- NaArray(x)
    type(naa) <- type

but the former is more convenient and will generally be more efficient.

The supported types for NaArray objects are "integer", "logical", "double", "complex", and "character".

Details

NaArray is a concrete subclass of the Array virtual class. This makes NaArray objects Array derivatives.

Like with SVT_SparseArray objects, the non-NA data in an NaArray object is stored in a Sparse Vector Tree. See ?SVT_SparseArray for more information.

Value

An NaArray or NaMatrix object.

See Also

Examples

## ---------------------------------------------------------------------
## Display details of class definition & known subclasses
## ---------------------------------------------------------------------

showClass("NaArray")

## ---------------------------------------------------------------------
## The NaArray() constructor
## ---------------------------------------------------------------------

naa1 <- NaArray(dim=5:3)  # all-NA object
naa1

naa2 <- NaArray(dim=c(35000, 2e6), type="integer")  # all-NA object
naa2

## Add some non-NA values to 'naa2':
naa2[cbind( 1:99, 2:100)] <-  1L
naa2[cbind(1:100, 1:100)] <-  0L
naa2[cbind(2:100,  1:99)] <- -1L
naa2

## The dimnames can be specified at construction time, or
## added/modified later:
naa3 <- NaArray(c(NA, NA, 1L, NA, 0:7, rep(NA, 4), 12:14, NA),
                dim=4:5, dimnames=list(letters[1:4], LETTERS[1:5]))
naa3

colnames(naa3) <- LETTERS[22:26]
naa3

## Sanity checks:
stopifnot(
  is(naa1, "NaArray"),
  identical(dim(naa1), 5:3),
  identical(as.array(naa1), array(dim=5:3)),
  is(naa2, "NaMatrix"),
  all.equal(dim(naa2), c(35000, 2e6)),
  identical(nnacount(naa2), 298L),
  is(naa3, "NaMatrix"),
  identical(dim(naa3), 4:5),
  identical(nnacount(naa3), 12L)
)

Combine multidimensional NaArray objects

Description

EXPERIMENTAL!!!

Like ordinary matrices and arrays in base R, NaMatrix objects can be combined by rows or columns, with rbind() or cbind(), and multidimensional NaArray objects can be bound along any dimension with abind().

Note that arbind() can also be used to combine the objects along their first dimension, and acbind() can be used to combine them along their second dimension.

See Also

Examples

# COMING SOON...

NaArray transposition

Description

EXPERIMENTAL!!!

Transpose an NaArray object by permuting its dimensions.

Value

COMING SOON...

See Also

Examples

# COMING SOON...

'Arith' operations on NaArray objects

Description

EXPERIMENTAL!!!

NaArray objects support all operations from the Arith group. See ?S4groupGeneric in the methods package for more information about the Arith group generic.

Note that NaArray of type() "complex" don't support Arith operations at the moment.

Details

Three forms of 'Arith' operations involving NaArray objects are supported:

  1. Between an NaArray object naa and a single value y: 

        naa op y
    y op naa

  2. Between two NaArray objects naa1 and naa2 of same dimensions (a.k.a. conformable arrays): 

        naa1 op naa2

  3. Between an NaArray object naa and an SVT_SparseArray object svt of same dimensions (a.k.a. conformable arrays): 

        naa op svt
    svt op naa

Value

An NaArray object of the same dimensions as the input object(s).

See Also

Examples

nam1 <- NaArray(dim=c(15, 6), type="integer")
nam1[cbind(1:15, 2)] <- 100:114
nam1[cbind(1:15, 5)] <- -(114:100)
nam1

nam1 * -0.01

nam1 * 10   # result is of type "double"
nam1 * 10L  # result is of type "integer"

nam1 / 10L

nam1 ^ 3.5

nam1 %% 5L
nam1 %/% 5L

nam2 <- NaArray(dim=dim(nam1), type="double")
nam2[c(2, 6, 12:17, 22:33, 55, 59:62, 90)] <- runif(26)
nam2

nam2 + nam1
nam2 - nam1
nam2 * nam1
nam2 / nam1
nam2 ^ nam1
nam2 %% nam1
nam2 %/% nam1

## Sanity checks:
m1 <- as.matrix(nam1)
m2 <- as.matrix(nam2)
stopifnot(
  identical(as.matrix(nam1 * -0.01), m1 * -0.01),
  identical(as.matrix(nam1 * 10), m1 * 10),
  identical(as.matrix(nam1 * 10L), m1 * 10L),
  identical(as.matrix(nam1 / 10L), m1 / 10L),
  identical(as.matrix(nam1 ^ 3.5), m1 ^ 3.5),
  identical(as.matrix(nam1 %% 5L), m1 %% 5L),
  identical(as.matrix(nam1 %/% 5L), m1 %/% 5L),
  identical(as.matrix(nam2 + nam1), m2 + m1),
  identical(as.matrix(nam2 - nam1), m2 - m1),
  identical(as.matrix(nam2 * nam1), m2 * m1),
  identical(as.matrix(nam2 / nam1), m2 / m1),
  all.equal(as.matrix(nam2 ^ nam1), m2 ^ m1),
  identical(as.matrix(nam2 %% nam1), m2 %% m1),
  identical(as.matrix(nam2 %/% nam1), m2 %/% m1)
)

'Compare' operations on NaArray objects

Description

EXPERIMENTAL!!!

NaArray objects support all operations from the Compare group. See ?S4groupGeneric in the methods package for more information about the Compare group generic.

Details

Three forms of 'Compare' operations involving NaArray objects are supported:

  1. Between an NaArray object naa and a single value y: 

        naa op y
    y op naa

  2. Between two NaArray objects naa1 and naa2 of same dimensions (a.k.a. conformable arrays): 

        naa1 op naa2

  3. Between an NaArray object naa and an SVT_SparseArray object svt of same dimensions (a.k.a. conformable arrays): 

        naa op svt
    svt op naa

Value

An NaArray object of type() "logical" and same dimensions as the input object(s).

See Also

Examples

nam1 <- NaArray(dim=c(15, 6), type="double")
nam1[c(2, 6, 12:17, 22:33, 55, 59:62, 90)] <- runif(26)
nam1

nam1 >= 0.2
nam1 != 0

nam2 <- NaArray(dim=dim(nam1), type="integer")
nam2[cbind(1:15, 2)] <- 100:114
nam2[cbind(1:15, 5)] <- -(114:100)
nam2

nam1 < nam2

## Sanity checks:
m1 <- as.matrix(nam1)
m2 <- as.matrix(nam2)
stopifnot(
  identical(as.matrix(nam1 >= 0.2), m1 >= 0.2),
  identical(as.matrix(nam1 != 0), m1 != 0),
  identical(as.matrix(nam1 < nam2), m1 < m2)
)

'Logic' operations on NaArray objects

Description

EXPERIMENTAL!!!

NaArray objects support operations from the Logic group (i.e. & and |), as well as logical negation (!). See ?S4groupGeneric in the methods package for more information about the Logic group generic.

Note that in base R, Logic operations support input of type() "logical", "integer", "double", or "complex". However, the corresponding methods for NaArray objects only support objects of type() "logical" for now.

Details

Three forms of 'Logic' operations involving NaArray objects are supported:

  1. Between an NaArray object naa and a single logical value y: 

        naa op y
    y op naa

  2. Between two NaArray objects naa1 and naa2 of same dimensions (a.k.a. conformable arrays): 

        naa1 op naa2

  3. Between an NaArray object naa and an SVT_SparseArray object svt of same dimensions (a.k.a. conformable arrays): 

        naa op svt
    svt op naa

    Note that, in this case, | returns an NaArray object but & returns an SVT_SparseArray object.

Value

An NaArray object of type() "logical" and same dimensions as the input object(s), except when & is used between an NaArray object and an SVT_SparseArray object in which case an SVT_SparseArray object is returned.

See Also

Examples

nam1 <- NaArray(dim=c(15, 6))
nam1[cbind(1:15, 2)] <- c(TRUE, FALSE, NA)
nam1[cbind(1:15, 5)] <- c(TRUE, NA, NA, FALSE, TRUE)
nam1

!nam1
nam1 & NA  # replaces all TRUE's with NA's
nam1 | NA  # replaces all FALSE's with NA's

nam2 <- NaArray(dim=dim(nam1))
nam2[c(2, 6, 12:17, 22:33, 55, 59:62, 90)] <- c(TRUE, NA)
nam2

nam1 & nam2
nam1 | nam2

## Sanity checks:
m1 <- as.matrix(nam1)
m2 <- as.matrix(nam2)
stopifnot(
  identical(as.matrix(!nam1), !m1),
  identical(as.matrix(nam1 & NA), m1 & NA),
  identical(as.matrix(nam1 | NA), m1 | NA),
  identical(as.matrix(nam1 & nam2), m1 & m2),
  identical(as.matrix(nam1 | nam2), m1 | m2)
)

'Math' and 'Math2' methods for NaArray objects

Description

EXPERIMENTAL!!!

NaArray objects support all operations from the Math and Math2 groups with a few exceptions. See ?S4groupGeneric in the methods package for more information about the Math and Math2 group generics.

Note that Math and Math2 operations only support NaArray objects of type() "double" at the moment. NaArray objects of type() "integer" are not supported yet.

Value

A NaArray derivative of the same dimensions as the input object.

See Also

Examples

nam <- NaArray(dim=c(15, 6))
nam[c(2, 6, 12:17, 22:33, 55, 59:62, 90)] <-
               c(runif(22)*1e4, Inf, -Inf, NA, NaN)

log(nam)
exp(nam)
cos(nam)
lgamma(nam)

## Sanity checks:
m <- as.matrix(nam)
stopifnot(
  suppressWarnings(identical(as.matrix(log(nam)), log(m))),
  identical(as.matrix(exp(nam)), exp(m)),
  suppressWarnings(identical(as.matrix(cos(nam)), cos(m))),
  suppressWarnings(identical(as.matrix(lgamma(nam)), lgamma(m)))
)

NaArray col/row summarization

Description

EXPERIMENTAL!!!

The SparseArray package provides memory-efficient col/row summarization methods (a.k.a. matrixStats methods) for NaArray objects, like colSums(), rowSums(), colMeans(), rowMeans(), etc...

Note that these are S4 generic functions defined in the MatrixGenerics package, with methods for ordinary matrices defined in the matrixStats package. This man page documents the methods defined for NaArray objects.

IMPORTANT NOTE: This is WORK-IN-PROGRESS! All the col*() methods listed below are supported. However, among the row*() methods, only rowAnyNAs(), rowMins(), rowMaxs(), rowRanges(), rowSums(), and rowSums2() are supported on NaArray objects at the moment.

Usage

## N.B.: Showing ONLY the col*() methods (usage of row*() methods is
## the same):

## S4 method for signature 'NaArray'
colAnyNAs(x, rows=NULL, cols=NULL, dims=1, ..., useNames=NA)

## S4 method for signature 'NaArray'
colAnys(x, rows=NULL, cols=NULL, na.rm=FALSE, dims=1, ..., useNames=NA)

## S4 method for signature 'NaArray'
colAlls(x, rows=NULL, cols=NULL, na.rm=FALSE, dims=1, ..., useNames=NA)

## S4 method for signature 'NaArray'
colMins(x, rows=NULL, cols=NULL, na.rm=FALSE, dims=1, ..., useNames=NA)

## S4 method for signature 'NaArray'
colMaxs(x, rows=NULL, cols=NULL, na.rm=FALSE, dims=1, ..., useNames=NA)

## S4 method for signature 'NaArray'
colRanges(x, rows=NULL, cols=NULL, na.rm=FALSE, dims=1, ..., useNames=NA)

## S4 method for signature 'NaArray'
colSums(x, na.rm=FALSE, dims=1)

## S4 method for signature 'NaArray'
colProds(x, rows=NULL, cols=NULL, na.rm=FALSE, dims=1, ..., useNames=NA)

## S4 method for signature 'NaArray'
colMeans(x, na.rm=FALSE, dims=1)

## S4 method for signature 'NaArray'
colSums2(x, rows=NULL, cols=NULL, na.rm=FALSE, dims=1, ..., useNames=NA)

## S4 method for signature 'NaArray'
colMeans2(x, rows=NULL, cols=NULL, na.rm=FALSE, dims=1, ..., useNames=NA)

## S4 method for signature 'NaArray'
colVars(x, rows=NULL, cols=NULL, na.rm=FALSE, center=NULL, dims=1,
           ..., useNames=NA)

## S4 method for signature 'NaArray'
colSds(x, rows=NULL, cols=NULL, na.rm=FALSE, center=NULL, dims=1,
          ..., useNames=NA)

Arguments

x

An NaMatrix or NaArray object.

rows, cols, ...

Not supported.

na.rm, useNames, center

See man pages of the corresponding generics in the MatrixGenerics package (e.g. ?MatrixGenerics::colVars) for a description of these arguments.

Note that, unlike the methods for ordinary matrices defined in the matrixStats package, the center argument of the colVars(), rowVars(), colSds(), and rowSds() methods for SparseArray objects can only be a single value (or a NULL). In particular, if x has more than one column, then center cannot be a vector with one value per column in x.

dims

See ?base::colSums for a description of this argument.

Details

These methods are typically used with na.rm=TRUE when called on an NaMatrix or NaArray object.

All these methods operate natively on the NaArray internal representation, for maximum efficiency.

Note that more col/row summarization methods might be added in the future.

Value

See man pages of the corresponding generics in the MatrixGenerics package (e.g. ?MatrixGenerics::colRanges) for the value returned by these methods.

Note

Most col*() methods for NaArray objects are multithreaded. See set_SparseArray_nthread for how to control the number of threads.

See Also

  • NaArray objects.

  • The man pages of the various generic functions defined in the MatrixGenerics package e.g. MatrixGenerics::colVars etc...

Examples

# COMING SOON...

Miscellaneous operations on a NaArray object

Description

This man page documents various base array operations that are supported by NaArray derivatives, and that didn't belong to any of the groups of operations documented in the other man pages of the SparseArray package.

Usage

# --- unary isometric array transformations ---

## S4 method for signature 'NaArray'
is.nan(x)

## S4 method for signature 'NaArray'
is.infinite(x)

# --- N-ary isometric array transformations ---

# COMING SOON...

Arguments

x

An NaArray object.

Details

More operations will be added in the future.

Value

is.nan() and is.infinite() return a SparseArray object of type() "logical" and same dimensions as the input object.

See Also

Examples

a <- array(c(NA, 2.77, NaN, Inf, NA, -Inf), dim=5:3)
naa <- NaArray(a)  # NaArray object
naa

is.nan(naa)            # SparseArray object of type "logical"
is.infinite(naa)       # SparseArray object of type "logical"

## Sanity checks:
res <- is.nan(naa)
stopifnot(is(res, "SparseArray"), type(res) == "logical",
          identical(as.array(res), is.nan(a)))
res <- is.infinite(naa)
stopifnot(is(res, "SparseArray"), type(res) == "logical",
          identical(as.array(res), is.infinite(a)))

Subsetting an NaArray object

Description

EXPERIMENTAL!!!

Like ordinary arrays in base R, NaArray objects support subsetting via the single bracket operator ([).

See Also

  • drop in base R to drop the ineffective dimensions of an array or array-like object.

  • Lindex2Mindex in the S4Arrays package for how to convert an L-index to an M-index and vice-versa.

  • NaArray objects.

  • [ and ordinary array objects in base R.

Examples

naa <- NaArray(dim=5:3)
naa[c(1:2, 8, 10, 15:17, 20, 24, 40, 56:60)] <- (1:15)*10L

## ---------------------------------------------------------------------
## N-dimensional subsetting
## ---------------------------------------------------------------------
naa[5:3, c(4,2,4), 2:3]
naa[ , c(4,2,4), 2:3]
naa[ , c(4,2,4), -1]
naa[ , c(4,2,4), 1]

naa2 <- naa[ , c(4,2,4), 1, drop=FALSE]
naa2

## Ineffective dimensions can always be dropped as a separate step:
drop(naa2)

naa[ , c(4,2,4), integer(0)]

dimnames(naa) <- list(letters[1:5], NULL, LETTERS[1:3])

naa[c("d", "a"), c(4,2,4), "C"]

naa2 <- naa["e", c(4,2,4), , drop=FALSE]
naa2

drop(naa2)

## ---------------------------------------------------------------------
## 1D-style subsetting (a.k.a. linear subsetting)
## ---------------------------------------------------------------------

## Using a numeric vector (L-index):
naa[c(60, 24, 21, 56)]

## Using a matrix subscript (M-index):
m <- rbind(c(5, 4, 3),
           c(4, 1, 2),
           c(1, 1, 2),
           c(1, 4, 3))
naa[m]

## See '?Lindex2Mindex' in the S4Arrays package for how to convert an
## L-index to an M-index and vice-versa.

## ---------------------------------------------------------------------
## Sanity checks
## ---------------------------------------------------------------------
a <- as.array(naa)
naa2 <- naa[5:3, c(4,2,4), 2:3]
a2   <- a  [5:3, c(4,2,4), 2:3]
stopifnot(identical(as.array(naa2), a2), identical(naa2, NaArray(a2)))
naa2 <- naa[ , c(4,2,4), 2:3]
a2   <- a  [ , c(4,2,4), 2:3]
stopifnot(identical(as.array(naa2), a2), identical(naa2, NaArray(a2)))
naa2 <- naa[ , c(4,2,4), -1]
a2   <- a  [ , c(4,2,4), -1]
stopifnot(identical(as.array(naa2), a2), identical(naa2, NaArray(a2)))
naa2 <- naa[ , c(4,2,4), 1]
a2   <- a  [ , c(4,2,4), 1]
stopifnot(identical(as.array(naa2), a2), identical(naa2, NaArray(a2)))
naa2 <- naa[ , c(4,2,4), 1, drop=FALSE]
a2   <- a  [ , c(4,2,4), 1, drop=FALSE]
stopifnot(identical(as.array(naa2), a2), identical(naa2, NaArray(a2)))
naa2 <- drop(naa2)
a2 <- drop(a2)
stopifnot(identical(as.array(naa2), a2), identical(naa2, NaArray(a2)))
naa2 <- naa[ , c(4,2,4), integer(0)]
a2   <- a  [ , c(4,2,4), integer(0)]
stopifnot(identical(as.array(naa2), a2),
          identical(unname(naa2), unname(NaArray(a2))))
naa2 <- naa[c("d", "a"), c(4,2,4), "C"]
a2   <- a  [c("d", "a"), c(4,2,4), "C"]
stopifnot(identical(as.array(naa2), a2), identical(naa2, NaArray(a2)))
naa2 <- naa["e", c(4,2,4), , drop=FALSE]
a2   <- a  ["e", c(4,2,4), , drop=FALSE]
stopifnot(identical(as.array(naa2), a2), identical(naa2, NaArray(a2)))
naa2 <- drop(naa2)
a2 <- drop(a2)
stopifnot(identical(as.array(naa2), a2), identical(naa2, NaArray(a2)))
stopifnot(identical(naa[c(60, 24, 21, 56)], naa[m]))

NaArray summarization methods

Description

EXPERIMENTAL!!!

The SparseArray package provides memory-efficient summarization methods for NaArray objects. The following methods are supported at the moment: anyNA(), any(), all(), min(), max(), range(), sum(), prod(), mean(), var(), sd().

More might be added in the future.

Note that these are S4 generic functions defined in base R and in the BiocGenerics package, with default methods defined in base R. This man page documents the methods defined for NaArray objects.

Details

All these methods operate natively on the NaArray representation, for maximum efficiency.

Value

See man pages of the corresponding default methods in the base package (e.g. ?base::range, ?base::mean, etc...) for the value returned by these methods.

See Also

  • NaArray objects.

  • The man pages of the various default methods defined in the base package e.g. base::range, base::mean, base::anyNA, etc...

Examples

naa <- NaArray(dim=c(4, 5, 2))
naa[c(1:2, 8, 10, 15:17, 24:26, 28, 40)] <- (1:12)*10L
naa

anyNA(naa)

range(naa, na.rm=TRUE)

sum(naa, na.rm=TRUE)

sd(naa, na.rm=TRUE)

## Sanity checks:
a0 <- as.array(naa)
stopifnot(
  identical(anyNA(naa), anyNA(a0)),
  identical(range(naa), range(a0)),
  identical(range(naa, na.rm=TRUE), range(a0, na.rm=TRUE)),
  identical(sum(naa), sum(a0)),
  identical(sum(naa, na.rm=TRUE), sum(a0, na.rm=TRUE)),
  all.equal(sd(naa, na.rm=TRUE), sd(a0, na.rm=TRUE))
)

Random SparseArray object

Description

randomSparseArray() and poissonSparseArray() can be used to generate a random SparseArray object efficiently.

Usage

randomSparseArray(dim, density=0.05, dimnames=NULL)
poissonSparseArray(dim, lambda=-log(0.95), density=NA, dimnames=NULL)

## Convenience wrappers for the 2D case:
randomSparseMatrix(nrow, ncol, density=0.05, dimnames=NULL)
poissonSparseMatrix(nrow, ncol, lambda=-log(0.95), density=NA,
                    dimnames=NULL)

Arguments

dim

The dimensions (specified as an integer vector) of the SparseArray object to generate.

density

The desired density (specified as a number >= 0 and <= 1) of the SparseArray object to generate, that is, the ratio between its number of nonzero elements and its total number of elements. This is nzcount(x)/length(x) or 1 - sparsity(x).

Note that for poissonSparseArray() and poissonSparseMatrix() density must be < 1 and the actual density of the returned object won't be exactly as requested but will typically be very close.

dimnames

The dimnames to put on the object to generate. Must be NULL or a list of length the number of dimensions. Each list element must be either NULL or a character vector along the corresponding dimension.

lambda

The mean of the Poisson distribution. Passed internally to the calls to rpois().

Only one of lambda and density can be specified.

When density is requested, rpois() is called internally with lambda set to -log(1 - density). This is expected to generate Poisson data with the requested density.

Finally note that the default value for lambda corresponds to a requested density of 0.05.

nrow, ncol

Number of rows and columns of the SparseMatrix object to generate.

Details

randomSparseArray() mimics the rsparsematrix() function from the Matrix package but returns a SparseArray object instead of a dgCMatrix object.

poissonSparseArray() populates a SparseArray object with Poisson data i.e. it's equivalent to: 

    a <- array(rpois(prod(dim), lambda), dim)
    as(a, "SparseArray")

but is faster and more memory efficient because intermediate dense array a is never generated.

Value

A SparseArray derivative (of class SVT_SparseArray or SVT_SparseMatrix) with the requested dimensions and density.

The type of the returned object is "double" for randomSparseArray() and randomSparseMatrix(), and "integer" for poissonSparseArray() and poissonSparseMatrix().

Note

Unlike with Matrix::rsparsematrix() there's no limit on the number of nonzero elements that can be contained in the returned SparseArray object.

For example Matrix::rsparsematrix(3e5, 2e4, density=0.5) will fail with an error but randomSparseMatrix(3e5, 2e4, density=0.5) should work (even though it will take some time and the memory footprint of the resulting object will be about 18 Gb).

See Also

Examples

## ---------------------------------------------------------------------
## randomSparseArray() / randomSparseMatrix()
## ---------------------------------------------------------------------
set.seed(123)
dgcm1 <- rsparsematrix(2500, 950, density=0.1)
set.seed(123)
svt1 <- randomSparseMatrix(2500, 950, density=0.1)
svt1
type(svt1)  # "double"

stopifnot(identical(as(svt1, "dgCMatrix"), dgcm1))

## ---------------------------------------------------------------------
## poissonSparseArray() / poissonSparseMatrix()
## ---------------------------------------------------------------------
svt2 <- poissonSparseMatrix(2500, 950, density=0.1)
svt2
type(svt2)  # "integer"
1 - sparsity(svt2)  # very close to the requested density

set.seed(123)
svt3 <- poissonSparseArray(c(600, 1700, 80), lambda=0.01)
set.seed(123)
a3 <- array(rpois(length(svt3), lambda=0.01), dim(svt3))
stopifnot(identical(svt3, SparseArray(a3)))

## The memory footprint of 'svt3' is 10x smaller than that of 'a3':
object.size(svt3)
object.size(a3)
as.double(object.size(a3) / object.size(svt3))

Read/write a sparse matrix from/to a CSV file

Description

Read/write a sparse matrix from/to a CSV (comma-separated values) file.

Usage

writeSparseCSV(x, filepath, sep=",", transpose=FALSE, write.zeros=FALSE,
                  chunknrow=250)

readSparseCSV(filepath, sep=",", transpose=FALSE)

Arguments

x

A matrix-like object, typically sparse. IMPORTANT: The object must have rownames and colnames! These will be written to the file.

Another requirement is that the object must be subsettable. More precisely: it must support 2D-style subsetting of the kind x[i, ] and x[ , j] where i and j are integer vectors of valid row and column indices.

filepath

The path (as a single string) to the file where to write the matrix-like object or to read it from. Compressed files are supported.

If "", writeSparseCSV() will write the data to the standard output connection.

Note that filepath can also be a connection.

sep

The field separator character. Values on each line of the file are separated by this character.

transpose

TRUE or FALSE. By default, rows in the matrix-like object correspond to lines in the CSV file. Set transpose to TRUE to transpose the matrix-like object on-the-fly, that is, to have its columns written to or read from the lines in the CSV file.

Note that using transpose=TRUE is semantically equivalent to calling t() on the object before writing it or after reading it, but it will tend to be more efficient. Also it will work even if x does not support t() (not all matrix-like objects are guaranteed to be transposable).

write.zeros

TRUE or FALSE. By default, the zero values in x are not written to the file. Set write.zeros to TRUE to write them.

chunknrow

writeSparseCSV() uses a block-processing strategy to try to speed up things. By default blocks of 250 rows (or columns if transpose=TRUE) are used. In our experience trying to increase this (e.g. to 500 or more) will generally not produce significant benefits while it will increase memory usage, so use carefully.

Value

writeSparseCSV returns an invisible NULL.

readSparseCSV returns a SparseMatrix object of class SVT_SparseMatrix.

See Also

Examples

## ---------------------------------------------------------------------
## writeSparseCSV()
## ---------------------------------------------------------------------

## Prepare toy matrix 'm0':
rownames0 <- LETTERS[1:6]
colnames0 <- letters[1:4]
m0 <- matrix(0L, nrow=length(rownames0), ncol=length(colnames0),
                 dimnames=list(rownames0, colnames0))
m0[c(1:2, 8, 10, 15:17, 24)] <- (1:8)*10L
m0

## writeSparseCSV():
writeSparseCSV(m0, filepath="", sep="\t")
writeSparseCSV(m0, filepath="", sep="\t", write.zeros=TRUE)
writeSparseCSV(m0, filepath="", sep="\t", transpose=TRUE)

## Note that writeSparseCSV() will automatically (and silently) coerce
## non-integer values to integer by passing them thru as.integer().

## Example where type(x) is "double":
m1 <- m0 * runif(length(m0))
m1
type(m1)
writeSparseCSV(m1, filepath="", sep="\t")

## Example where type(x) is "logical":
writeSparseCSV(m0 != 0, filepath="", sep="\t")

## Example where type(x) is "raw":
m2 <- m0
type(m2) <- "raw"
m2
writeSparseCSV(m2, filepath="", sep="\t")

## ---------------------------------------------------------------------
## readSparseCSV()
## ---------------------------------------------------------------------

csv_file <- tempfile()
writeSparseCSV(m0, csv_file)

svt1 <- readSparseCSV(csv_file)
svt1

svt2 <- readSparseCSV(csv_file, transpose=TRUE)
svt2

## If you need the sparse data as a dgCMatrix object, just coerce the
## returned object:
as(svt1, "dgCMatrix")
as(svt2, "dgCMatrix")

## Sanity checks:
stopifnot(identical(m0, as.matrix(svt1)))
stopifnot(identical(t(m0), as.matrix(svt2)))

rowsum() methods for sparse matrices

Description

The SparseArray package provides memory-efficient rowsum() and colsum() methods for SparseMatrix and dgCMatrix objects.

Usage

## S4 method for signature 'SparseMatrix'
rowsum(x, group, reorder=TRUE, ...)

## S4 method for signature 'dgCMatrix'
rowsum(x, group, reorder=TRUE, ...)

## S4 method for signature 'SparseMatrix'
colsum(x, group, reorder=TRUE, ...)

## S4 method for signature 'dgCMatrix'
colsum(x, group, reorder=TRUE, ...)

Arguments

x

A SparseMatrix or dgCMatrix object.

group, reorder

See ?base::rowsum for a description of these arguments.

...

Like the default S3 rowsum() method defined in the base package, the methods documented in this man page support additional argument na.rm, set to FALSE by default. If TRUE, missing values (NA or NaN) are omitted from the calculations.

Value

An ordinary matrix, like the default rowsum() method. See ?base::rowsum for how the matrix returned by the default rowsum() method is obtained.

See Also

  • rowsum in base R.

  • S4Arrays::rowsum in the S4Arrays package for the rowsum() and colsum() S4 generic functions.

  • SparseMatrix objects.

  • dgCMatrix objects implemented in the Matrix package.

Examples

svt0 <- randomSparseMatrix(7e5, 100, density=0.15)
dgcm0 <- as(svt0, "dgCMatrix")
m0 <- as.matrix(svt0)

group <- sample(10, nrow(m0), replace=TRUE)

## Calling rowsum() on the sparse representations is usually faster
## than on the dense representation:
rs1 <- rowsum(m0, group)
rs2 <- rowsum(svt0, group)   # about 3x faster
rs3 <- rowsum(dgcm0, group)  # also about 3x faster

## Sanity checks:
stopifnot(identical(rs1, rs2))
stopifnot(identical(rs1, rs3))

SparseArray objects

Description

The SparseArray package defines the SparseArray virtual class whose purpose is to be extended by other S4 classes that aim at representing in-memory multidimensional sparse arrays.

It has currently two concrete subclasses, COO_SparseArray and SVT_SparseArray, both also defined in this package. Each subclass uses its own internal representation for the nonzero multidimensional data, the COO layout for COO_SparseArray, and the SVT layout for SVT_SparseArray. The two layouts are described in the COO_SparseArray and SVT_SparseArray man pages, respectively.

Finally, the package also defines the SparseMatrix virtual class, as a subclass of the SparseArray class, for the specific 2D case.

Usage

## Constructor function:
SparseArray(x, type=NA)

Arguments

x

An ordinary matrix or array, or a dg[C|R]Matrix object, or an lg[C|R]Matrix object, or any matrix-like or array-like object that supports coercion to SVT_SparseArray.

type

A single string specifying the requested type of the object.

By default, the SparseArray object returned by the constructor function has the same type() as x. However the user can use the type argument to request a different type. Note that doing: 

    sa <- SparseArray(x, type=type)

is equivalent to doing: 

    sa <- SparseArray(x)
    type(sa) <- type

but the former is more convenient and will generally be more efficient.

Supported types are all R atomic types plus "list".

Details

The SparseArray class extends the Array virtual class defined in the S4Arrays package. Here is the full SparseArray sub-hierarchy as defined in the SparseArray package (virtual classes are marked with an asterisk): 

: Array class :                 Array*
: hierarchy   :                   ^
                                  |
- - - - - - - - - - - - - - - - - | - - - - - - - - - - - - - - -
: SparseArray   :            SparseArray*
: sub-hierarchy :            ^    ^    ^
                             |    |    |
                 COO_SparseArray  |  SVT_SparseArray
                        ^         |         ^
- - - - - - - - - - - - | - - - - | - - - - | - - - - - - - - - -
: SparseMatrix      :   |    SparseMatrix*  |
: sub-sub-hierarchy :   |    ^         ^    |
                        |    |         |    |
                 COO_SparseMatrix    SVT_SparseMatrix

Any object that belongs to a class that extends SparseArray e.g. (a SVT_SparseArray or SVT_SparseMatrix object) is called a SparseArray derivative.

Most of the standard matrix and array API defined in base R should work on SparseArray derivatives, including dim(), length(), dimnames(), `dimnames<-`(), [, drop(), `[<-` (subassignment), t(), rbind(), cbind(), etc...

SparseArray derivatives also support type(), `type<-`(), is_sparse(), nzcount(), nzwhich(), nzvals(), `nzvals<-`(), sparsity(), arbind(), and acbind().

Value

A SparseArray derivative, that is a SVT_SparseArray, COO_SparseArray, SVT_SparseMatrix, or COO_SparseMatrix object.

The type() of the input object is preserved, except if a different one was requested via the type argument.

What is considered a zero depends on the type():

  • "logical" zero is FALSE;

  • "integer" zero is 0L;

  • "double" zero is 0;

  • "complex" zero is 0+0i;

  • "raw" zero is raw(1);

  • "character" zero is "" (empty string);

  • "list" zero is NULL.

See Also

Examples

## ---------------------------------------------------------------------
## Display details of class definition & known subclasses
## ---------------------------------------------------------------------

showClass("SparseArray")

## ---------------------------------------------------------------------
## The SparseArray() constructor
## ---------------------------------------------------------------------

a <- array(rpois(9e6, lambda=0.3), dim=c(500, 3000, 6))
SparseArray(a)    # an SVT_SparseArray object

m <- matrix(rpois(9e6, lambda=0.3), ncol=500)
SparseArray(m)    # an SVT_SparseMatrix object

dgc <- sparseMatrix(i=c(4:1, 2:4, 9:12, 11:9), j=c(1:7, 1:7),
                    x=runif(14), dims=c(12, 7))
class(dgc)
SparseArray(dgc)  # an SVT_SparseMatrix object

dgr <- as(dgc, "RsparseMatrix")
class(dgr)
SparseArray(dgr)  # a COO_SparseMatrix object

## ---------------------------------------------------------------------
## nzcount(), nzwhich(), nzvals(), `nzvals<-`()
## ---------------------------------------------------------------------
x <- SparseArray(a)

## Get the number of nonzero array elements in 'x':
nzcount(x)

## nzwhich() returns the indices of the nonzero array elements in 'x'.
## Either as an integer (or numeric) vector of length 'nzcount(x)'
## containing "linear indices":
nzidx <- nzwhich(x)
length(nzidx)
head(nzidx)

## Or as an integer matrix with 'nzcount(x)' rows and one column per
## dimension where the rows represent "array indices" (a.k.a. "array
## coordinates"):
Mnzidx <- nzwhich(x, arr.ind=TRUE)
dim(Mnzidx)

## Each row in the matrix is an n-tuple representing the "array
## coordinates" of a nonzero element in 'x':
head(Mnzidx)
tail(Mnzidx)

## Extract the values of the nonzero array elements in 'x' and return
## them in a vector "parallel" to 'nzwhich(x)':
x_nzvals <- nzvals(x)  # equivalent to 'x[nzwhich(x)]'
length(x_nzvals)
head(x_nzvals)

nzvals(x) <- log1p(nzvals(x))
x

## Sanity checks:
stopifnot(identical(nzidx, which(a != 0)))
stopifnot(identical(Mnzidx, which(a != 0, arr.ind=TRUE, useNames=FALSE)))
stopifnot(identical(x_nzvals, a[nzidx]))
stopifnot(identical(x_nzvals, a[Mnzidx]))
stopifnot(identical(`nzvals<-`(x, nzvals(x)), x))

Combine multidimensional SparseArray objects

Description

Like ordinary matrices and arrays in base R, SparseMatrix derivatives can be combined by rows or columns, with rbind() or cbind(), and multidimensional SparseArray derivatives can be bound along any dimension with abind().

Note that arbind() can also be used to combine the objects along their first dimension, and acbind() can be used to combine them along their second dimension.

See Also

Examples

## ---------------------------------------------------------------------
## COMBINING SparseMatrix OBJECTS
## ---------------------------------------------------------------------

m1a <- matrix(1:15, nrow=3, ncol=5,
              dimnames=list(NULL, paste0("M1y", 1:5)))
m1b <- matrix(101:135, nrow=7, ncol=5,
              dimnames=list(paste0("M2x", 1:7), paste0("M2y", 1:5)))
sm1a <- SparseArray(m1a)
sm1b <- SparseArray(m1b)

rbind(sm1a, sm1b)

## ---------------------------------------------------------------------
## COMBINING SparseArray OBJECTS WITH 3 DIMENSIONS
## ---------------------------------------------------------------------

a2a <- array(1:105, dim=c(5, 7, 3),
             dimnames=list(NULL, paste0("A1y", 1:7), NULL))
a2b <- array(1001:1105, dim=c(5, 7, 3),
             dimnames=list(paste0("A2x", 1:5), paste0("A2y", 1:7), NULL))
sa2a <- SparseArray(a2a)
sa2b <- SparseArray(a2b)

abind(sa2a, sa2b)               # same as 'abind(sa2a, sa2b, along=3)'
abind(sa2a, sa2b, rev.along=0)  # same as 'abind(sa2a, sa2b, along=4)'

a3a <- array(1:60, dim=c(3, 5, 4),
             dimnames=list(NULL, paste0("A1y", 1:5), NULL))
a3b <- array(101:240, dim=c(7, 5, 4),
             dimnames=list(paste0("A2x", 1:7), paste0("A2y", 1:5), NULL))
sa3a <- SparseArray(a3a)
sa3b <- SparseArray(a3b)

arbind(sa3a, sa3b)  # same as 'abind(sa3a, sa3b, along=1)'

## ---------------------------------------------------------------------
## Sanity checks
## ---------------------------------------------------------------------

sm1 <- rbind(sm1a, sm1b)
m1 <- rbind(m1a, m1b)
stopifnot(identical(as.array(sm1), m1), identical(sm1, SparseArray(m1)))

sa2 <- abind(sa2a, sa2b)
stopifnot(identical(sa2, abind(sa2a, sa2b, along=3)))
a2 <- abind(a2a, a2b, along=3)
stopifnot(identical(as.array(sa2), a2), identical(sa2, SparseArray(a2)))

sa2 <- abind(sa2a, sa2b, rev.along=0)
stopifnot(identical(sa2, abind(sa2a, sa2b, along=4)))
a2 <- abind(a2a, a2b, along=4)
stopifnot(identical(as.array(sa2), a2), identical(sa2, SparseArray(a2)))

sa3 <- arbind(sa3a, sa3b)
a3 <- arbind(a3a, a3b)
stopifnot(identical(as.array(sa3), a3), identical(sa3, SparseArray(a3)))

SparseArray transposition

Description

EXPERIMENTAL!!!

Transpose a SparseArray object by permuting its dimensions.

Value

COMING SOON...

See Also

Examples

# COMING SOON...

'Arith' operations on SparseArray objects

Description

SparseArray derivatives support operations from the Arith group, with some restrictions. See ?S4groupGeneric in the methods package for more information about the Arith group generic.

IMPORTANT NOTES:

Details

Two forms of 'Arith' operations are supported:

  1. Between an SVT_SparseArray object svt and a single value y: 

        svt op y
    y op svt

    The Arith operations that support this form are: *, /, ^, %%,%/%. Note that, except for * (for which both svt * y and y * svt are supported), single value y must be on the right e.g. svt ^ 3.

  2. Between two SVT_SparseArray objects svt1 and svt2 of same dimensions (a.k.a. conformable arrays): 

        svt1 op svt2

    The Arith operations that support this form are: +, -, *.

Value

A SparseArray derivative of the same dimensions as the input object(s).

See Also

Examples

## ---------------------------------------------------------------------
## Basic examples
## ---------------------------------------------------------------------

svt1 <- SVT_SparseArray(dim=c(15, 6), type="integer")
svt1[cbind(1:15, 2)] <- 100:114
svt1[cbind(1:15, 5)] <- -(114:100)
svt1

svt1 * -0.01

svt1 * 10   # result is of type "double"
svt1 * 10L  # result is of type "integer"

svt1 / 10L

svt1 ^ 3.5

svt1 %% 5L
svt1 %/% 5L

svt2 <- SVT_SparseArray(dim=dim(svt1), type="double")
svt2[c(2, 6, 12:17, 22:33, 55, 59:62, 90)] <- runif(26)
svt2

svt1 + svt2
svt1 - svt2
svt1 * svt2

svt2 * (0.1 * svt1 - svt2 ^ 2) + svt1 / sum(svt2)

## Sanity checks:
m1 <- as.matrix(svt1)
m2 <- as.matrix(svt2)
stopifnot(
  identical(as.matrix(svt1 * -0.01), m1 * -0.01),
  identical(as.matrix(svt1 * 10), m1 * 10),
  identical(as.matrix(svt1 * 10L), m1 * 10L),
  identical(as.matrix(svt1 / 10L), m1 / 10L),
  identical(as.matrix(svt1 ^ 3.5), m1 ^ 3.5),
  identical(as.matrix(svt1 %% 5L), m1 %% 5L),
  identical(as.matrix(svt1 %/% 5L), m1 %/% 5L),
  identical(as.matrix(svt1 + svt2), m1 + m2),
  identical(as.matrix(svt1 - svt2), m1 - m2),
  identical(as.matrix(svt1 * svt2), m1 * m2),
  all.equal(as.matrix(svt2 * (0.1 * svt1 - svt2 ^ 2) + svt1 / sum(svt2)),
            m2 * (0.1 * m1 - m2 ^ 2) + m1 / sum(m2))
)

## ---------------------------------------------------------------------
## An example combining operations from the 'Arith', 'Compare',
## and 'Logic' groups
## ---------------------------------------------------------------------

m3 <- matrix(0L, nrow=15, ncol=6)
m3[c(2, 6, 12:17, 22:33, 55, 59:62, 90)] <- 101:126
svt3 <- SparseArray(m3)

## Can be 5x or 10x faster than with a dgCMatrix object on a big
## SVT_SparseMatrix object!
svt4 <- (svt3^1.5 + svt3) %% 100 - 0.2 * svt3 > 0
svt4

## Sanity check:
m4 <- (m3^1.5 + m3) %% 100 - 0.2 * m3 > 0
stopifnot(identical(as.matrix(svt4), m4))

'Compare' operations on SparseArray objects

Description

SparseArray derivatives support operations from the Compare group, with some restrictions. See ?S4groupGeneric in the methods package for more information about the Compare group generic.

IMPORTANT NOTE: Only SVT_SparseArray objects are supported at the moment. Support for COO_SparseArray objects might be added in the future.

Details

Two forms of 'Compare' operations are supported:

  1. Between an SVT_SparseArray object svt and a single value y: 

        svt op y
    y op svt

    All operations from the Compare group support this form, with single value y either on the left or the right. However, there are some operation-dependent restrictions on the value of y.

  2. Between two SVT_SparseArray objects svt1 and svt2 of same dimensions (a.k.a. conformable arrays): 

        svt1 op svt2

    The Compare operations that support this form are: !=, <, >.

Value

A SparseArray derivative of type() "logical" and same dimensions as the input object(s).

See Also

Examples

svt1 <- SVT_SparseArray(dim=c(15, 6), type="double")
svt1[c(2, 6, 12:17, 22:33, 55, 59:62, 90)] <- runif(26)
svt1

svt1 >= 0.2
svt1 != 0

## Sanity checks:
m1 <- as.matrix(svt1)
stopifnot(
  identical(as.matrix(svt1 >= 0.2), m1 >= 0.2),
  identical(as.matrix(svt1 != 0), m1 != 0)
)

'Complex' methods for SparseArray objects

Description

WORK-IN-PROGRESS

Value

COMING SOON...

See Also

Examples

# COMING SOON...

'Logic' operations on SparseArray objects

Description

SparseArray derivatives support operations from the Logic group (i.e. & and |), with some restrictions. See ?S4groupGeneric in the methods package for more information about the Logic group generic.

IMPORTANT NOTES:

  • Only SVT_SparseArray objects are supported at the moment. Support for COO_SparseArray objects might be added in the future.

  • In base R, Logic operations support input of type() "logical", "integer", "double", or "complex". However, the corresponding methods for SVT_SparseArray objects only support objects of type() "logical" for now.

Value

A SparseArray derivative of type() "logical" and same dimensions as the input object(s).

See Also

Examples

svt1 <- svt2 <- SVT_SparseArray(dim=c(15, 6))
svt1[cbind(1:15, 2)] <- c(TRUE, FALSE, NA)
svt1[cbind(1:15, 5)] <- c(TRUE, NA, NA, FALSE, TRUE)
svt2[c(2, 6, 12:17, 22:33, 55, 59:62, 90)] <- c(TRUE, NA)

svt1 & svt2
svt1 | svt2

## Sanity checks:
m1 <- as.matrix(svt1)
m2 <- as.matrix(svt2)
stopifnot(
  identical(as.matrix(svt1 & svt2), m1 & m2),
  identical(as.matrix(svt1 | svt2), m1 | m2)
)

'Math' and 'Math2' methods for SparseArray objects

Description

SparseArray derivatives support a subset of operations from the Math and Math2 groups. See ?S4groupGeneric in the methods package for more information about the Math and Math2 group generics.

IMPORTANT NOTES:

  • Only operations from these groups that preserve sparsity are supported. For example, sqrt(), trunc(), log1p(), and sin() are supported, but cumsum(), log(), cos(), or gamma() are not.

  • Only SVT_SparseArray objects are supported at the moment. Support for COO_SparseArray objects might be added in the future.

  • Math and Math2 operations only support SVT_SparseArray objects of type() "double" at the moment.

Value

A SparseArray derivative of the same dimensions as the input object.

See Also

Examples

m <- matrix(0, nrow=15, ncol=6)
m[c(2, 6, 12:17, 22:33, 55, 59:62, 90)] <-
    c(runif(22)*1e4, Inf, -Inf, NA, NaN)
svt <- SparseArray(m)

svt2 <- trunc(sqrt(svt))
svt2

## Sanity check:
m2 <- suppressWarnings(trunc(sqrt(m)))
stopifnot(identical(as.matrix(svt2), m2))

SparseArray col/row summarization

Description

The SparseArray package provides memory-efficient col/row summarization methods (a.k.a. matrixStats methods) for SparseArray objects, like colSums(), rowSums(), colMedians(), rowMedians(), colVars(), rowVars(), etc...

Note that these are S4 generic functions defined in the MatrixGenerics package, with methods for ordinary matrices defined in the matrixStats package. This man page documents the methods defined for SparseArray objects.

Usage

## N.B.: Showing ONLY the col*() methods (usage of row*() methods is
## the same):

## S4 method for signature 'SparseArray'
colAnyNAs(x, rows=NULL, cols=NULL, dims=1, ..., useNames=NA)

## S4 method for signature 'SparseArray'
colAnys(x, rows=NULL, cols=NULL, na.rm=FALSE, dims=1, ..., useNames=NA)

## S4 method for signature 'SparseArray'
colAlls(x, rows=NULL, cols=NULL, na.rm=FALSE, dims=1, ..., useNames=NA)

## S4 method for signature 'SparseArray'
colMins(x, rows=NULL, cols=NULL, na.rm=FALSE, dims=1, ..., useNames=NA)

## S4 method for signature 'SparseArray'
colMaxs(x, rows=NULL, cols=NULL, na.rm=FALSE, dims=1, ..., useNames=NA)

## S4 method for signature 'SparseArray'
colRanges(x, rows=NULL, cols=NULL, na.rm=FALSE, dims=1, ..., useNames=NA)

## S4 method for signature 'SparseArray'
colSums(x, na.rm=FALSE, dims=1)

## S4 method for signature 'SparseArray'
colProds(x, rows=NULL, cols=NULL, na.rm=FALSE, dims=1, ..., useNames=NA)

## S4 method for signature 'SparseArray'
colMeans(x, na.rm=FALSE, dims=1)

## S4 method for signature 'SparseArray'
colSums2(x, rows=NULL, cols=NULL, na.rm=FALSE, dims=1, ..., useNames=NA)

## S4 method for signature 'SparseArray'
colMeans2(x, rows=NULL, cols=NULL, na.rm=FALSE, dims=1, ..., useNames=NA)

## S4 method for signature 'SparseArray'
colVars(x, rows=NULL, cols=NULL, na.rm=FALSE, center=NULL, dims=1,
           ..., useNames=NA)

## S4 method for signature 'SparseArray'
colSds(x, rows=NULL, cols=NULL, na.rm=FALSE, center=NULL, dims=1,
          ..., useNames=NA)

## S4 method for signature 'SparseArray'
colMedians(x, rows=NULL, cols=NULL, na.rm=FALSE, ..., useNames=NA)

Arguments

x

A SparseMatrix or SparseArray object.

Note that the colMedians() and rowMedians() methods only support 2D objects (i.e. SparseMatrix objects) at the moment.

rows, cols, ...

Not supported.

na.rm, useNames, center

See man pages of the corresponding generics in the MatrixGenerics package (e.g. ?MatrixGenerics::colVars) for a description of these arguments.

Note that, unlike the methods for ordinary matrices defined in the matrixStats package, the center argument of the colVars(), rowVars(), colSds(), and rowSds() methods for SparseArray objects can only be a single value (or a NULL). In particular, if x has more than one column, then center cannot be a vector with one value per column in x.

dims

See ?base::colSums for a description of this argument. Note that all the methods above support it, except colMedians() and rowMedians().

Details

All these methods operate natively on the SVT_SparseArray internal representation, for maximum efficiency.

Note that more col/row summarization methods might be added in the future.

Value

See man pages of the corresponding generics in the MatrixGenerics package (e.g. ?MatrixGenerics::colRanges) for the value returned by these methods.

Note

Most col*() methods for SparseArray objects are multithreaded. See set_SparseArray_nthread for how to control the number of threads.

See Also

  • SparseArray objects.

  • The man pages of the various generic functions defined in the MatrixGenerics package e.g. MatrixGenerics::colVars etc...

Examples

## ---------------------------------------------------------------------
## 2D CASE
## ---------------------------------------------------------------------
m0 <- matrix(0L, nrow=6, ncol=4, dimnames=list(letters[1:6], LETTERS[1:4]))
m0[c(1:2, 8, 10, 15:17, 24)] <- (1:8)*10L
m0["e", "B"] <- NA
svt0 <- SparseArray(m0)
svt0

colSums(svt0)
colSums(svt0, na.rm=TRUE)

rowSums(svt0)
rowSums(svt0, na.rm=TRUE)

colMeans(svt0)
colMeans(svt0, na.rm=TRUE)

colRanges(svt0)
colRanges(svt0, useNames=FALSE)
colRanges(svt0, na.rm=TRUE)
colRanges(svt0, na.rm=TRUE, useNames=FALSE)

colVars(svt0)
colVars(svt0, useNames=FALSE)

## Sanity checks:
stopifnot(
  identical(colSums(svt0), colSums(m0)),
  identical(colSums(svt0, na.rm=TRUE), colSums(m0, na.rm=TRUE)),
  identical(rowSums(svt0), rowSums(m0)),
  identical(rowSums(svt0, na.rm=TRUE), rowSums(m0, na.rm=TRUE)),
  identical(colMeans(svt0), colMeans(m0)),
  identical(colMeans(svt0, na.rm=TRUE), colMeans(m0, na.rm=TRUE)),
  identical(colRanges(svt0), colRanges(m0, useNames=TRUE)),
  identical(colRanges(svt0, useNames=FALSE), colRanges(m0, useNames=FALSE)),
  identical(colRanges(svt0, na.rm=TRUE),
            colRanges(m0, na.rm=TRUE, useNames=TRUE)),
  identical(colVars(svt0), colVars(m0, useNames=TRUE)),
  identical(colVars(svt0, na.rm=TRUE),
            colVars(m0, na.rm=TRUE, useNames=TRUE))
)

## ---------------------------------------------------------------------
## 3D CASE (AND ARBITRARY NUMBER OF DIMENSIONS)
## ---------------------------------------------------------------------
set.seed(2009)
svt <- 6L * (poissonSparseArray(5:3, density=0.35) -
             poissonSparseArray(5:3, density=0.35))
dimnames(svt) <- list(NULL, letters[1:4], LETTERS[1:3])

cs1 <- colSums(svt)
cs1  # cs1[j , k] is equal to sum(svt[ , j, k])

cs2 <- colSums(svt, dims=2)
cs2  # cv2[k] is equal to sum(svt[ , , k])

cv1 <- colVars(svt)
cv1  # cv1[j , k] is equal to var(svt[ , j, k])

cv2 <- colVars(svt, dims=2) 
cv2  # cv2[k] is equal to var(svt[ , , k])

## Sanity checks:
k_idx <- setNames(seq_len(dim(svt)[3]), dimnames(svt)[[3]])
j_idx <- setNames(seq_len(dim(svt)[2]), dimnames(svt)[[2]])
cv1b <- sapply(k_idx, function(k)
                      sapply(j_idx, function(j) var(svt[ , j, k, drop=FALSE])))
cv2b <- sapply(k_idx, function(k) var(svt[ , , k]))
stopifnot(
  identical(colSums(svt), colSums(as.array(svt))),
  identical(colSums(svt, dims=2), colSums(as.array(svt), dims=2)),
  identical(cv1, cv1b),
  identical(cv2, cv2b)
)

Miscellaneous operations on a SparseArray object

Description

This man page documents various base array operations that are supported by SparseArray derivatives, and that didn't belong to any of the groups of operations documented in the other man pages of the SparseArray package.

Usage

# --- unary isometric array transformations ---

## S4 method for signature 'COO_SparseArray'
is.na(x)
## S4 method for signature 'SVT_SparseArray'
is.na(x)

## S4 method for signature 'COO_SparseArray'
is.nan(x)
## S4 method for signature 'SVT_SparseArray'
is.nan(x)

## S4 method for signature 'COO_SparseArray'
is.infinite(x)
## S4 method for signature 'SVT_SparseArray'
is.infinite(x)

## S4 method for signature 'COO_SparseArray'
tolower(x)

## S4 method for signature 'COO_SparseArray'
toupper(x)

## S4 method for signature 'COO_SparseArray'
nchar(x, type="chars", allowNA=FALSE, keepNA=NA)

# --- N-ary isometric array transformations ---

## S4 method for signature 'SparseArray'
pmin(..., na.rm=FALSE)
## S4 method for signature 'SparseArray'
pmax(..., na.rm=FALSE)

Arguments

x

A SparseArray derivative.

type, allowNA, keepNA

See ?base::nchar for a description of these arguments.

...

SparseArray derivatives.

na.rm

See ?base::pmin for a description of this argument.

Details

More operations will be added in the future.

Value

See man pages of the corresponding base functions (e.g. ?base::is.na, ?base::nchar, ?base::pmin, etc...) for the value returned by these methods.

Note that, like the base functions, the methods documented in this man page are endomorphisms i.e. they return an array-like object of the same class as the input.

See Also

Examples

a <- array(c(0, 2.77, NA, 0, NaN, -Inf), dim=5:3)
svt <- SparseArray(a)  # SVT_SparseArray object
class(svt)

is.na(svt)             # SVT_SparseArray object of type "logical"
is.nan(svt)            # SVT_SparseArray object of type "logical"
is.infinite(svt)       # SVT_SparseArray object of type "logical"

svt1 <- poissonSparseMatrix(500, 20, density=0.2)
svt2 <- poissonSparseMatrix(500, 20, density=0.25) * 0.77
pmin(svt1, svt2)
pmax(svt1, svt2)

## Sanity checks:
res <- is.na(svt)
stopifnot(is(res, "SVT_SparseArray"), type(res) == "logical",
          identical(as.array(res), is.na(a)))
res <- is.nan(svt)
stopifnot(is(res, "SVT_SparseArray"), type(res) == "logical",
          identical(as.array(res), is.nan(a)))
res <- is.infinite(svt)
stopifnot(is(res, "SVT_SparseArray"), type(res) == "logical",
          identical(as.array(res), is.infinite(a)))
res <- pmin(svt1, svt2)
stopifnot(is(res, "SVT_SparseArray"),
          identical(as.array(res), pmin(as.array(svt1), as.array(svt2))))
res <- pmax(svt1, svt2)
stopifnot(is(res, "SVT_SparseArray"),
          identical(as.array(res), pmax(as.array(svt1), as.array(svt2))))

SparseArray subassignment

Description

Like ordinary arrays in base R, SparseArray derivatives support subassignment via the [<- operator.

See Also

Examples

a <- array(0L, dim=5:3)
a[c(1:2, 8, 10, 15:17, 20, 24, 40, 56:60)] <- (1:15)*10L
svt <- SparseArray(a)
svt

svt[5:3, c(4,2,4), 2:3] <- -99L

## Sanity checks:
a[5:3, c(4,2,4), 2:3] <- -99L
stopifnot(identical(as.array(svt), a), identical(svt, SparseArray(a)))

Subsetting a SparseArray object

Description

Like ordinary arrays in base R, SparseArray derivatives support subsetting via the single bracket operator ([).

See Also

  • drop in base R to drop the ineffective dimensions of an array or array-like object.

  • Lindex2Mindex in the S4Arrays package for how to convert an L-index to an M-index and vice-versa.

  • SparseArray objects.

  • [ and ordinary array objects in base R.

Examples

a <- array(0L, dim=5:3)
a[c(1:2, 8, 10, 15:17, 20, 24, 40, 56:60)] <- (1:15)*10L
svt <- SparseArray(a)
svt

## ---------------------------------------------------------------------
## N-dimensional subsetting
## ---------------------------------------------------------------------
svt[5:3, c(4,2,4), 2:3]
svt[ , c(4,2,4), 2:3]
svt[ , c(4,2,4), -1]
svt[ , c(4,2,4), 1]

svt2 <- svt[ , c(4,2,4), 1, drop=FALSE]
svt2

## Ineffective dimensions can always be dropped as a separate step:
drop(svt2)

svt[ , c(4,2,4), integer(0)]

dimnames(a) <- list(letters[1:5], NULL, LETTERS[1:3])
svt <- SparseArray(a)

svt[c("d", "a"), c(4,2,4), "C"]

svt2 <- svt["e", c(4,2,4), , drop=FALSE]
svt2

drop(svt2)

## ---------------------------------------------------------------------
## 1D-style subsetting (a.k.a. linear subsetting)
## ---------------------------------------------------------------------

## Using a numeric vector (L-index):
svt[c(60, 24, 21, 56)]

## Using a matrix subscript (M-index):
m <- rbind(c(5, 4, 3),
           c(4, 1, 2),
           c(1, 1, 2),
           c(1, 4, 3))
svt[m]

## See '?Lindex2Mindex' in the S4Arrays package for how to convert an
## L-index to an M-index and vice-versa.

## ---------------------------------------------------------------------
## Sanity checks
## ---------------------------------------------------------------------
svt2 <- svt[5:3, c(4,2,4), 2:3]
a2   <- a  [5:3, c(4,2,4), 2:3]
stopifnot(identical(as.array(svt2), a2), identical(svt2, SparseArray(a2)))
svt2 <- svt[ , c(4,2,4), 2:3]
a2   <- a  [ , c(4,2,4), 2:3]
stopifnot(identical(as.array(svt2), a2), identical(svt2, SparseArray(a2)))
svt2 <- svt[ , c(4,2,4), -1]
a2   <- a  [ , c(4,2,4), -1]
stopifnot(identical(as.array(svt2), a2), identical(svt2, SparseArray(a2)))
svt2 <- svt[ , c(4,2,4), 1]
a2   <- a  [ , c(4,2,4), 1]
stopifnot(identical(as.array(svt2), a2), identical(svt2, SparseArray(a2)))
svt2 <- svt[ , c(4,2,4), 1, drop=FALSE]
a2   <- a  [ , c(4,2,4), 1, drop=FALSE]
stopifnot(identical(as.array(svt2), a2), identical(svt2, SparseArray(a2)))
svt2 <- drop(svt2)
a2 <- drop(a2)
stopifnot(identical(as.array(svt2), a2), identical(svt2, SparseArray(a2)))
svt2 <- svt[ , c(4,2,4), integer(0)]
a2   <- a  [ , c(4,2,4), integer(0)]
stopifnot(identical(as.array(svt2), a2),
          identical(unname(svt2), unname(SparseArray(a2))))
svt2 <- svt[c("d", "a"), c(4,2,4), "C"]
a2   <- a  [c("d", "a"), c(4,2,4), "C"]
stopifnot(identical(as.array(svt2), a2), identical(svt2, SparseArray(a2)))
svt2 <- svt["e", c(4,2,4), , drop=FALSE]
a2   <- a  ["e", c(4,2,4), , drop=FALSE]
stopifnot(identical(as.array(svt2), a2), identical(svt2, SparseArray(a2)))
svt2 <- drop(svt2)
a2 <- drop(a2)
stopifnot(identical(as.array(svt2), a2), identical(svt2, SparseArray(a2)))
stopifnot(identical(svt[c(60, 24, 21, 56)], svt[m]))

SparseArray summarization methods

Description

The SparseArray package provides memory-efficient summarization methods for SparseArray objects. The following methods are supported at the moment: anyNA(), any(), all(), min(), max(), range(), sum(), prod(), mean(), var(), sd().

More might be added in the future.

Note that these are S4 generic functions defined in base R and in the BiocGenerics package, with default methods defined in base R. This man page documents the methods defined for SparseArray objects.

Details

All these methods operate natively on the COO_SparseArray or SVT_SparseArray representation, for maximum efficiency.

Value

See man pages of the corresponding default methods in the base package (e.g. ?base::range, ?base::mean, etc...) for the value returned by these methods.

See Also

  • SparseArray objects.

  • The man pages of the various default methods defined in the base package e.g. base::range, base::mean, base::anyNA, etc...

Examples

svt0 <- SVT_SparseArray(dim=c(4, 5, 2))
svt0[c(1:2, 8, 10, 15:17, 24:26, 28, 40)] <- (1:12)*10L
svt0[4, 3, 1] <- NA
svt0

anyNA(svt0)

range(svt0)

range(svt0, na.rm=TRUE)

sum(svt0, na.rm=TRUE)

sd(svt0, na.rm=TRUE)

## Sanity checks:
a0 <- as.array(svt0)
stopifnot(
  identical(anyNA(svt0), anyNA(a0)),
  identical(range(svt0), range(a0)),
  identical(range(svt0, na.rm=TRUE), range(a0, na.rm=TRUE)),
  identical(sum(svt0), sum(a0)),
  identical(sum(svt0, na.rm=TRUE), sum(a0, na.rm=TRUE)),
  all.equal(sd(svt0, na.rm=TRUE), sd(a0, na.rm=TRUE))
)

SparseMatrix multiplication and cross-product

Description

Like ordinary matrices in base R, SparseMatrix derivatives can be multiplied with the %*% operator. They also support crossprod() and tcrossprod().

Value

The %*%, crossprod() and tcrossprod() methods for SparseMatrix objects always return an ordinary matrix of type() "double".

Note

Matrix multiplication and cross-product of SparseMatrix derivatives are multithreaded. See set_SparseArray_nthread for how to control the number of threads.

See Also

  • %*% and crossprod in base R.

  • SparseMatrix objects.

  • S4Arrays::type in the S4Arrays package to get the type of the elements of an array-like object.

  • Ordinary matrix objects in base R.

Examples

m1 <- matrix(0L, nrow=15, ncol=6)
m1[c(2, 6, 12:17, 22:33, 55, 59:62, 90)] <- 101:126
svt1 <- as(m1, "SVT_SparseMatrix")

set.seed(333)
svt2 <- poissonSparseMatrix(nrow=6, ncol=7, density=0.2)

svt1 %*% svt2
m1   %*% svt2

## Unary crossprod() and tcrossprod():
crossprod(svt1)               # same as t(svt1) %*% svt1
tcrossprod(svt1)              # same as svt1 %*% t(svt1)

## Binary crossprod() and tcrossprod():
crossprod(svt1[1:6, ], svt2)  # same as t(svt1[1:6, ]) %*% svt2
tcrossprod(svt1, t(svt2))     # same as svt1 %*% svt2

## Sanity checks:
m12 <- m1 %*% as.matrix(svt2)
stopifnot(
  identical(svt1 %*% svt2, m12),
  identical(m1 %*% svt2, m12),
  identical(crossprod(svt1), t(svt1) %*% svt1),
  identical(tcrossprod(svt1), svt1 %*% t(svt1)),
  identical(crossprod(svt1[1:6, ], svt2), t(svt1[1:6, ]) %*% svt2),
  identical(tcrossprod(svt1, t(svt2)), m12)
)

SVT_SparseArray objects

Description

The SVT_SparseArray class is a new container for efficient in-memory representation of multidimensional sparse arrays. It uses the SVT layout to represent the nonzero multidimensional data internally.

An SVT_SparseMatrix object is an SVT_SparseArray object of 2 dimensions.

Note that SVT_SparseArray and SVT_SparseMatrix objects replace the older and less efficient COO_SparseArray and COO_SparseMatrix objects.

Usage

## Constructor function:
SVT_SparseArray(x, dim=NULL, dimnames=NULL, type=NA)

Arguments

x

If dim is NULL (the default) then x must be an ordinary matrix or array, or a dgCMatrix/lgCMatrix object, or any matrix-like or array-like object that supports coercion to SVT_SparseArray.

If dim is provided then x can either be missing, a vector (atomic or list), or an array-like object. If missing, then an allzero SVT_SparseArray object will be constructed. Otherwise x will be used to fill the returned object (length(x) must be <= prod(dim)). Note that if x is an array-like object then its dimensions are ignored i.e. it's treated as a vector.

dim

NULL or the dimensions (supplied as an integer vector) of the SVT_SparseArray or SVT_SparseMatrix object to construct. If NULL (the default) then the returned object will have the dimensions of matrix-like or array-like object x.

dimnames

The dimnames of the object to construct. Must be NULL or a list of length the number of dimensions. Each list element must be either NULL or a character vector along the corresponding dimension. If both dim and dimnames are NULL (the default) then the returned object will have the dimnames of matrix-like or array-like object x.

type

A single string specifying the requested type of the object.

Normally, the SVT_SparseArray object returned by the constructor function has the same type() as x but the user can use the type argument to request a different type. Note that doing: 

    svt <- SVT_SparseArray(x, type=type)

is equivalent to doing: 

    svt <- SVT_SparseArray(x)
    type(svt) <- type

but the former is more convenient and will generally be more efficient.

Supported types are all R atomic types plus "list".

Details

SVT_SparseArray is a concrete subclass of the SparseArray virtual class. This makes SVT_SparseArray objects SparseArray derivatives.

The nonzero data in a SVT_SparseArray object is stored in a Sparse Vector Tree. We'll refer to this internal data representation as the SVT layout. See the "SVT layout" section below for more information.

The SVT layout is similar to the CSC layout (compressed, sparse, column-oriented format) used by CsparseMatrix derivatives from the Matrix package, like dgCMatrix or lgCMatrix objects, but with the following improvements:

  • The SVT layout supports sparse arrays of arbitrary dimensions.

  • With the SVT layout, the sparse data can be of any type. Whereas CsparseMatrix derivatives only support sparse data of type "double" or "logical" at the moment.

  • The SVT layout imposes no limit on the number of nonzero elements that can be stored. With dgCMatrix/lgCMatrix objects, this number must be < 2^31.

  • Overall, the SVT layout allows more efficient operations on SVT_SparseArray objects.

Value

An SVT_SparseArray or SVT_SparseMatrix object.

SVT layout

An SVT (Sparse Vector Tree) is a tree of depth N - 1 where N is the number of dimensions of the sparse array.

The leaves in the tree can only be of two kinds: NULL or leaf vector. Leaves that are leaf vectors can only be found at the deepest level in the tree (i.e. at depth N - 1). All leaves found at a lower depth must be NULLs.

A leaf vector represents a sparse vector along the first dimension (a.k.a. innermost or fastest moving dimension) of the sparse array. It contains a collection of offset/value pairs sorted by strictly ascending offset. More precisely, a leaf vector is represented by an ordinary list of 2 parallel dense vectors:

  1. nzvals: a vector (atomic or list) of nonzero values (zeros are not allowed);

  2. nzoffs: an integer vector of offsets (i.e. 0-based positions).

The 1st vector determines the type of the leaf vector i.e. "double", "integer", "logical", etc... All the leaf vectors in the SVT must have the same type as the sparse array.

It's useful to realize that a leaf vector simply represents a 1D SVT.

In SparseArray 1.5.4 a new type of leaf vector was introduced called lacunar leaf. A lacunar leaf is a non-empty leaf vector where the nzvals component is set to NULL. In this case the nonzero values are implicit: they're all considered to be equal to one.

Examples:

  • An SVT_SparseArray object with 1 dimension has its nonzero data stored in an SVT of depth 0. Such SVT is represented by a single leaf vector.

  • An SVT_SparseArray object with 2 dimensions has its nonzero data stored in an SVT of depth 1. Such SVT is represented by a list of length the extend of the 2nd dimension (number of columns). Each list element is an SVT of depth 0 (as described above), or a NULL if the corresponding column is empty (i.e. has no nonzero data).

    For example, the nonzero data of an 8-column sparse matrix will be stored in an SVT that looks like this: 

        .------------------list-of-length-8-----------------.
   /       /       /      |       |      \       \       \
  |       |       |       |       |       |       |       |
 leaf    leaf    NULL    leaf    leaf    leaf    leaf    NULL
vector  vector          vector  vector  vector  vector

    The NULL leaves represent the empty columns (i.e. the columns with no nonzero elements).

  • An SVT_SparseArray object with 3 dimensions has its nonzero data stored in an SVT of depth 2. Such SVT is represented by a list of length the extend of the 3rd dimension. Each list element must be an SVT of depth 1 (as described above) that stores the nonzero data of the corresponding 2D slice, or a NULL if the 2D slice is empty (i.e. has no nonzero data).

  • And so on...

See Also

  • The SparseArray class for the virtual parent class of COO_SparseArray and SVT_SparseArray.

  • S4 classes dgCMatrix and lgCMatrix defined in the Matrix package, for the de facto standard of sparse matrix representations in the R ecosystem.

  • Virtual class CsparseMatrix defined in the Matrix package for the parent class of all classes that use the "CSC layout".

  • The Matrix::rsparsematrix function in the Matrix package.

  • Ordinary array objects in base R.

Examples

## ---------------------------------------------------------------------
## BASIC CONSTRUCTION
## ---------------------------------------------------------------------
SVT_SparseArray(dim=5:3)  # allzero object

SVT_SparseArray(dim=c(35000, 2e6), type="raw")  # allzero object

## Use a dgCMatrix object to fill the SVT_SparseArray object to construct:
x <- rsparsematrix(10, 16, density=0.1)  # random dgCMatrix object
SVT_SparseArray(x, dim=c(8, 5, 4))

svt1 <- SVT_SparseArray(dim=c(12, 5, 2))  # allzero object
svt1[cbind(11, 2:5, 2)] <- 22:25
svt1

svt2 <- SVT_SparseArray(dim=c(6, 4), type="integer",
                        dimnames=list(letters[1:6], LETTERS[1:4]))
svt2[c(1:2, 8, 10, 15:17, 24)] <- (1:8)*10L
svt2

## ---------------------------------------------------------------------
## CSC (Compressed Sparse Column) LAYOUT VS SVT LAYOUT
## ---------------------------------------------------------------------

## dgCMatrix objects from the Matrix package use the CSC layout:
dgcm2 <- as(svt2, "dgCMatrix")
dgcm2@x  # nonzero values
dgcm2@i  # row indices of the nonzero values
dgcm2@p  # breakpoints (0 followed by one breakpoint per column)

str(svt2)

m3 <- matrix(rpois(54e6, lambda=0.4), ncol=1200)

## Note that 'SparseArray(m3)' can also be used for this:
svt3 <- SVT_SparseArray(m3)
svt3

dgcm3 <- as(m3, "dgCMatrix")

## Compare type and memory footprint:
type(svt3)
object.size(svt3)
type(dgcm3)
object.size(dgcm3)

## Transpose:
system.time(svt <- t(t(svt3)))
system.time(dgcm <- t(t(dgcm3)))
identical(svt, svt3)
identical(dgcm, dgcm3)

## rbind():
m4 <- matrix(rpois(45e6, lambda=0.4), ncol=1200)
svt4 <- SVT_SparseArray(m4)
dgcm4 <- as(m4, "dgCMatrix")

system.time(rbind(svt3, svt4))
system.time(rbind(dgcm3, dgcm4))

Number of threads used by SparseArray operations

Description

Use get_SparseArray_nthread or set_SparseArray_nthread to get or set the number of threads to use by the multithreaded operations implemented in the SparseArray package.

Usage

get_SparseArray_nthread()
set_SparseArray_nthread(nthread=NULL)

Arguments

nthread

The number of threads to use by multithreaded operations implemented in the SparseArray package.

On systems where OpenMP is available, this must be NULL or an integer value >= 1. When NULL (the default), a "reasonable" value will be used that never exceeds one third of the number of logical cpus available on the machine.

On systems where OpenMP is not available, the supplied nthread is ignored and set_SparseArray_nthread() is a no-op.

Details

Multithreaded operations in the SparseArray package are implemented in C with OpenMP (https://www.openmp.org/).

Note that OpenMP is not available on all systems. On systems where it's available, get_SparseArray_nthread() is guaranteed to return a value >= 1. On systems where it's not available (e.g. macOS), get_SparseArray_nthread() returns 0 and set_SparseArray_nthread() is a no-op.

IMPORTANT: The portable way to disable multithreading is by calling set_SparseArray_nthread(1), NOT set_SparseArray_nthread(0) (the latter returns an error on systems where OpenMP is available).

Value

get_SparseArray_nthread() returns an integer value >= 1 on systems where OpenMP is available, and 0 on systems where it's not.

set_SparseArray_nthread() returns the previous nthread value, that is, the value returned by get_SparseArray_nthread() before the call to set_SparseArray_nthread(). Note that the value is returned invisibly.

See Also

Examples

get_SparseArray_nthread()

if (get_SparseArray_nthread() != 0) {  # multithreading is available
    svt1 <- poissonSparseMatrix(77000L, 15000L, density=0.01)

    ## 'user' time is typically N x 'elapsed' time where N is roughly the
    ## number of threads that was effectively used:
    system.time(cv1 <- colVars(svt1))

    svt2 <- poissonSparseMatrix(77000L, 300L, density=0.3) * 0.77
    system.time(cp12 <- crossprod(svt1, svt2))

    prev_nthread <- set_SparseArray_nthread(1)  # disable multithreading
    system.time(cv1 <- colVars(svt1))
    system.time(cp12 <- crossprod(svt1, svt2))

    ## Restore previous 'nthread' value:
    set_SparseArray_nthread(prev_nthread)
}