# matvec

From statmod v1.2.3
by Gordon Smyth

##### Multiply a Matrix by a Vector

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`

.

##### Examples

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

*Documentation reproduced from package statmod, version 1.2.3, License: LGPL version 2 or newer*

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