# asMatrixWeights: asMatrixWeights In limma: Linear Models for Microarray Data

## Description

Convert probe-weights or array-weights to a matrix of weights.

## Usage

 `1` ```asMatrixWeights(weights, dim) ```

## Arguments

 `weights` numeric matrix of weights, rows corresponding to probes and columns to arrays. Or vector of probe weights. Or vector of array weights. `dim` numeric dimension vector of length 2, i.e., the number of probes and the number of arrays.

## Details

This function converts a vector or probe-weights or a vector of array-weights to a matrix of the correct size. Probe-weights are repeated across rows while array-weights are repeated down the columns. If `weights` has length equal to the number of probes, it is assumed to contain probe-weights. If it has length equal to the number of arrays, it is assumed to contain array-weights. If the number of probes is equal to the number of arrays, then `weights` is assumed to contain array-weights if it is a row-vector of the correct size, i.e., if it is a matrix with one row.

This function is used internally by the linear model fitting functions in limma.

## Value

Numeric matrix of dimension `dim`.

## Author(s)

Gordon Smyth

`modifyWeights`.

An overview of functions in LIMMA used for fitting linear models is given in 06.LinearModels.

## Examples

 ```1 2``` ```asMatrixWeights(1:3,c(4,3)) asMatrixWeights(1:4,c(4,3)) ```

### Example output

```     [,1] [,2] [,3]
[1,]    1    2    3
[2,]    1    2    3
[3,]    1    2    3
[4,]    1    2    3
attr(,"arrayweights")
[1] TRUE
[,1] [,2] [,3]
[1,]    1    1    1
[2,]    2    2    2
[3,]    3    3    3
[4,]    4    4    4
```

limma documentation built on Nov. 8, 2020, 8:28 p.m.