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rowProds

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

Description

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

Usage

product(x, idxs = NULL, na.rm = FALSE, ...)

rowProds(x, rows = NULL, cols = NULL, na.rm = FALSE,
  method = c("direct", "expSumLog"), ...)

colProds(x, rows = NULL, cols = NULL, na.rm = FALSE,
  method = c("direct", "expSumLog"), ...)

Arguments

x

A numeric NxK matrix.
idxs, rows, cols

A vector indicating subset of elements (or rows and/or columns) to operate over. If NULL, no subsetting is done.
na.rm

If TRUE, missing values are ignored, otherwise not.
...

Not used.
method

A character string specifying how each product is calculated.

Details

If method = "expSumLog", then then product() function is used, which calculates the product via the logarithmic transform (treating negative values specially). This improves the precision and lowers the risk for numeric overflow. If method = "direct", the direct product is calculated via the prod() function.

Value

Returns a numeric vector of length N (K).

Missing values

Note, if method = "expSumLog", na.rm = FALSE, and x contains missing values (NA or NaN), then the calculated value is also missing value. Note that it depends on platform whether NaN or NA is returned when an NaN exists, cf. is.nan().

Author(s)

Henrik Bengtsson

matrixStats

Functions that Apply to Rows and Columns of Matrices (and to Vectors)

v0.58.0
Artistic-2.0
Authors
Henrik Bengtsson [aut, cre, cph], Constantin Ahlmann-Eltze [ctb], Hector Corrada Bravo [ctb], Robert Gentleman [ctb], Jan Gleixner [ctb], Peter Hickey [ctb], Ola Hossjer [ctb], Harris Jaffee [ctb], Dongcan Jiang [ctb], Peter Langfelder [ctb], Brian Montgomery [ctb], Hugh Parsonage [ctb]
Initial release

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