colProds-xgCMatrix-method: Calculates the product for each row (column) in a matrix

In const-ae/sparseMatrixStats: Summary Statistics for Rows and Columns of Sparse Matrices

Calculates the product for each row (column) in a matrix

Description

Calculates the product for each row (column) in a matrix

Usage

## S4 method for signature 'xgCMatrix'
colProds(x, rows = NULL, cols = NULL, na.rm = FALSE, useNames = TRUE)

## S4 method for signature 'xgCMatrix'
rowProds(x, rows = NULL, cols = NULL, na.rm = FALSE, useNames = TRUE)

Arguments

x	An NxK matrix-like object.
rows, cols	A vector indicating the subset of rows (and/or columns) to operate over. If NULL, no subsetting is done.
na.rm	If TRUE, missing values (NA or NaN) are omitted from the calculations.
useNames	If TRUE (default), names attributes of result are set. Else if FALSE, no naming support is done.

Details

Attention: This method ignores the order of the values, because it assumes that the product is commutative. Unfortunately, for 'double' this is not true. For example 'NaN * NA = NaN', but 'NA * NaN = NA'. This is relevant for this function if there are '+-Inf', because 'Inf * 0 = NaN'. This function returns 'NA' whenever there is 'NA' in the input. This is different from 'matrixStats::colProds()'.

Value

Returns a numeric vector of length N (K).

See Also

• matrixStats::rowProds() and matrixStats::colProds() which are used when the input is a matrix or numeric vector.

• For sums across rows (columns), see rowSums2() (colSums2())

• base::prod().

Examples

mat <- matrix(rnorm(15), nrow = 5, ncol = 3)
mat[2, 1] <- NA
mat[3, 3] <- Inf
mat[4, 1] <- 0

print(mat)

rowProds(mat)
colProds(mat)

const-ae/sparseMatrixStats documentation built on June 15, 2024, 9:36 a.m.