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riskRegression (version 2023.12.21)

rowSumsCrossprod: Apply crossprod and rowSums

Description

Fast computation of crossprod(rowSums(X),Y)

Usage

rowSumsCrossprod(X, Y, transposeY)

Value

A vector of length m.

Arguments

X

A matrix with dimensions n*k. Hence the result of rowSums(X) has length n.

Y

A matrix with dimenions n*m. Can be a matrix with dimension m*n but then transposeY should be TRUE.

transposeY

Logical. If TRUE transpose Y before matrix multiplication.

Author

Thomas Alexander Gerds <tag@biostat.ku.dk>

Examples

Run this code
x <- matrix(1:10,nrow=5)
y <- matrix(1:20,ncol=4)
rowSumsCrossprod(x,y,0)

x <- matrix(1:10,nrow=5)
y <- matrix(1:20,ncol=5)
rowSumsCrossprod(x,y,1)

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