matvec {statmod} | 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)

[Package

*statmod* version 1.2.4

Index]