# Full or fractional factorial design matrix generation

### Description

The function generates the design matrix provided the number of 2-levels design factors and defining relations.

### Usage

1 | ```
ffDesMatrix(k, gen = NULL)
``` |

### Arguments

`k` |
numeric. The number of 2-levels design factors in the designs. |

`gen` |
list. If |

### Details

A defining relation is declared by a vector where the first entry
corresponds to the left hand side (LHS) of the defining
equation. For example, if `k=5`

, and `gen=list(c(-5,1,2,3,4))`

,
then the defining equation is *-5=1*2*3*4*. A full 2-levels (-1,1)
factorial design is generated. For each defining relation the LHS column
is replaced by the corresponding columns product. At the end repeated
runs are removed from the matrix.

### Value

The function returns a 2-levels design matrix with `k`

columns.

### Author(s)

Ernesto Barrios

### See Also

`conf.design`

of the
conf.design package,
`FrF2`

from the FrF2 package.

### Examples

1 2 3 | ```
ffDesMatrix(5) # Full 2^5 factorial design
ffDesMatrix(5,gen=list(c(5,1,2,3,4))) # 2^(5-1) factorial design
ffDesMatrix(5,gen=list(c(4,1,2),c(-5,1,3))) # 2^(5-2) factorial design
``` |