matvec {limma} | R Documentation

## Multiply a Matrix by a Vector

### Description

Multiply the rows or columns of a matrix by the elements of a vector.

### Usage

    matvec(M, v)
    vecmat(v, M)

### Arguments

`M` | numeric matrix, or object which can be coerced to a matrix.
`v` | numeric vector, or object which can be coerced to a vector. Length should match the number of columns of `M` (for `matvec`) or the number of rows of `M` (for `vecmat`)

### Details

`matvec(M,v)` is equivalent to `M %*% diag(v)` but is faster to execute. Similarly `vecmat(v,M)` is equivalent to `diag(v) %*% M` but is faster to execute.

### Value

A matrix of the same dimensions as `M`.

### Author(s)

Gordon Smyth

### Examples

    A <- matrix(1:12,3,4)
    A
    matvec(A,c(1,2,3,4))
    vecmat(c(1,2,3),A)

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