Package 'proxyC'

Maximum/minimum values in columns or rows

Description

Produce the same result as apply(x, 2, max), apply(x, 1, max), apply(x, 2, min) and apply(x, 1, min), respectively, but ignore NA.

Usage

colMaxs(x, use_nan = FALSE)

rowMaxs(x, use_nan = FALSE)

colMins(x, use_nan = FALSE)

rowMins(x, use_nan = FALSE)

Arguments

x	a base::matrix or Matrix::Matrix object.
use_nan	if TRUE, return NaN for columns or rows with all zero. Only used when x is a sparse matrix.

Value

a numeric vector

Examples

mt <- Matrix::rsparsematrix(100, 100, 0.9)
  colMaxs(mt)
  apply(mt, 2, max) # the same

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Standard deviation of columns and rows of large matrices

Description

Produce the same result as apply(x, 2, sd) and apply(x, 1, sd), respectively. without coercing matrix to dense matrix. Values are not identical to sd() because of the floating point precision issue in C++.

Usage

colSds(x, use_nan = FALSE)

rowSds(x, use_nan = FALSE)

Arguments

x	a base::matrix or Matrix::Matrix object.
use_nan	if TRUE, return NaN for columns or rows with all zero. Only used when x is a sparse matrix.

Value

a numeric vector

Examples

mt <- Matrix::rsparsematrix(100, 100, 0.9)
colSds(mt)
apply(mt, 2, sd) # the same

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Number of zeros in columns and rows of large matrices

Description

Produce the same result as applying sum(x == 0) to each row or column.

Usage

colZeros(x)

rowZeros(x)

Arguments

x	a base::matrix or Matrix::Matrix object.

Value

an integer vector

Examples

mt <- Matrix::rsparsematrix(100, 100, 0.9)
colZeros(mt)
apply(mt, 2, function(x) sum(x == 0)) # the same

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Cross-product of large sparse matrices

Description

Compute the (transposed) cross-product of large sparse matrices using the same infrastructure as simil() and dist().

Usage

crossprod(x, y = NULL, min_prod = NULL, sparse = TRUE, digits = 14)

tcrossprod(x, y = NULL, min_prod = NULL, sparse = TRUE, digits = 14)

Arguments

x	a base::matrix or Matrix::Matrix object. Only sparse matrices are covered to the Matrix::CsparseMatrix internally.
y	if a base::matrix or Matrix::Matrix object is provided, proximity between documents or features in x and y is computed.
min_prod	the minimum product to be recorded.
sparse	if TRUE, returns Matrix::sparseMatrix object. When neither min_simil nor rank is used, dense matrices require less space in RAM.
digits	determines rounding of small values towards zero. Use primarily to correct floating point errors. Rounding is performed in C++ in a similar way as base::zapsmall.

Value

a Matrix::Matrix object

---

Create a pattern matrix for masking

Description

Create a pattern matrix for simil() or dist() to enable masked similarity computation. If the matrix is passed to the function, it computes similarity scores only for cells with TRUE.

Usage

mask(x, y = NULL)

Arguments

x	a numeric or character vector matched against each other.
y	a numeric or character vector matched against x if provided.

Value

a sparse logical matrix with TRUE for matched pairs.

Examples

mt1 <- Matrix::rsparsematrix(100, 6, 1.0)
colnames(mt1) <- c("a", "a", "d", "d", "e", "e")
mt2 <- Matrix::rsparsematrix(100, 5, 1.0)
colnames(mt2) <- c("a", "b", "c", "d", "e")

(msk <- mask(colnames(mt1), colnames(mt2)))
simil(mt1, mt2, margin = 2, mask = msk, drop0 = TRUE)

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Column or row indices of maximum values

Description

Find column or row indices of maximum values in matrices. Works in a similar way as base::max.col() but without conversion of sparse matrices to dense matrices.

Usage

maxCol(x, ties_method = c("random", "first", "last"), use_nan = FALSE)

maxRow(x, ties_method = c("random", "first", "last"), use_nan = FALSE)

Arguments

x	a base::matrix or Matrix::Matrix object.
ties_method	specify how to handle ties. If "random", choose an index randomly within the ties; if "first" or "last" returns the index of the first or the last tie elements, respectively.
use_nan	if TRUE, return NA for columns or rows with all zero. Applies only when x is a sparse matrix.

Value

an integer vector

Examples

mt <- Matrix::rsparsematrix(100, 100, 0.9)
maxCol(mt, ties_method = "first")
max.col(mt, ties.method = "first") # the same

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Compute similarity/distance between rows or columns of large matrices

Description

Fast similarity/distance computation function for large matrices using multiple processors. To save computation time and storage, it can also apply arbitrary threshold (min_simil) or rank (rank) to the similarity/distance scores and return them in a sparse matrix.

Usage

simil(
  x,
  y = NULL,
  margin = 1,
  method = c("cosine", "correlation", "dice", "edice", "jaccard", "ejaccard", "fjaccard",
    "hamann", "faith", "simple matching"),
  mask = NULL,
  min_simil = NULL,
  rank = NULL,
  drop0 = FALSE,
  diag = FALSE,
  use_nan = NULL,
  sparse = TRUE,
  digits = 14
)

dist(
  x,
  y = NULL,
  margin = 1,
  method = c("euclidean", "chisquared", "kullback", "jeffreys", "jensen", "manhattan",
    "maximum", "canberra", "minkowski", "hamming"),
  mask = NULL,
  p = 2,
  smooth = 0,
  drop0 = FALSE,
  diag = FALSE,
  use_nan = NULL,
  sparse = TRUE,
  digits = 14
)

Arguments

x	a base::matrix or Matrix::Matrix object. Only sparse matrices are covered to the Matrix::CsparseMatrix internally.
y	if a base::matrix or Matrix::Matrix object is provided, proximity between documents or features in x and y is computed.
margin	integer indicating margin of similarity/distance computation. 1 indicates rows or 2 indicates columns.
method	method to compute similarity or distance
mask	a pattern matrix created using mask() for masked similarity/distance computation. The shape of the matrix must be the same as the resulting matrix. Cannot be used when diag = TRUE.
min_simil	the minimum similarity value to be recorded.
rank	an integer value specifying top-n most similarity values to be recorded.
drop0	if TRUE, removes zero values to make the similarity/distance matrix sparse. It has no effect when dense = TRUE.
diag	if TRUE, only compute diagonal elements of the similarity/distance matrix; useful when comparing corresponding rows or columns of x and y.
use_nan	if TRUE, returns NaN if the standard deviation of a vector is zero when method is "correlation"; if all the values are zero in a vector when method is "cosine", "chisquared", "kullback", "jeffreys" or "jensen". Note that use of NaN makes the similarity/distance matrix denser and therefore larger in RAM. If FALSE, return zero in same use situations as above. If NULL, will also return zero but also generate a warning (default).
sparse	if TRUE, returns Matrix::sparseMatrix object. When neither min_simil nor rank is used, dense matrices require less space in RAM.
digits	determines rounding of small values towards zero. Use primarily to correct floating point errors. Rounding is performed in C++ in a similar way as base::zapsmall.
p	weight for Minkowski distance.
smooth	adds a fixed value to all the cells to avoid division by zero. Only used when method is "chisquared", "kullback", "jeffreys" or "jensen".

Details

Available Methods

Similarity:

• cosine: cosine similarity

• correlation: Pearson's correlation

• jaccard: Jaccard coefficient

• ejaccard: the real value version of jaccard

• fjaccard: Fuzzy Jaccard coefficient

• dice: Dice coefficient

• edice: the real value version of dice

• hamann: Hamann similarity

• faith: Faith similarity

• ⁠simple matching⁠: the percentage of common elements

Distance:

• euclidean: Euclidean distance

• chisquared: chi-squared distance

• kullback: Kullback–Leibler divergence

• jeffreys: Jeffreys divergence

• jensen: Jensen–Shannon divergence

• manhattan: Manhattan distance

• maximum: the largest difference between values

• canberra: Canberra distance

• minkowski: Minkowski distance

• hamming: Hamming distance

See the vignette for how the similarity and distance are computed: vignette("measures", package = "proxyC")

Parallel Computing

It performs parallel computing using Intel oneAPI Threads Building Blocks. The number of threads for parallel computing should be specified via options(proxyC.threads) before calling the functions. If the value is -1, all the available threads will be used. Unless the option is used, the number of threads will be limited by the environmental variables (OMP_THREAD_LIMIT or RCPP_PARALLEL_NUM_THREADS) to comply with CRAN policy and offer backward compatibility.

Value

a Matrix::Matrix object

See Also

zapsmall

Examples

mt <- Matrix::rsparsematrix(100, 100, 0.01)
simil(mt, method = "cosine")[1:5, 1:5]
mt <- Matrix::rsparsematrix(100, 100, 0.01)
dist(mt, method = "euclidean")[1:5, 1:5]

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