compatible.formula.terms {cvms} | R Documentation |

## Compatible formula terms

### Description

`162,660`

pairs of compatible terms for building model formulas with up to `15`

fixed effects.

### Format

A `data.frame`

with `162,660`

rows and `5`

variables:

- left
term, fixed effect or interaction, with fixed effects separated by "`*`

"

- right
term, fixed effect or interaction, with fixed effects separated by "`*`

"

- max_interaction_size
maximum interaction size in the two terms, up to `3`

- num_effects
number of unique fixed effects in the two terms, up to `5`

- min_num_fixed_effects
minimum number of fixed effects required to use a formula with the two terms,
i.e. the index in the alphabet of the last of the alphabetically ordered effects (letters) in the two terms,
so `4`

if `left == "A"`

and `right == "D"`

### Details

A term is either a fixed effect or an interaction between fixed effects (up to three-way), where
the effects are separated by the "`*`

" operator.

Two terms are compatible if they are not redundant,
meaning that both add a fixed effect to the formula. E.g. as the interaction
`"x1 * x2 * x3"`

expands to `"x1 + x2 + x3 + x1 * x2 + x1 * x3 + x2 * x3 + x1 * x2 * x3"`

,
the higher order interaction makes these "sub terms" redundant. Note: All terms are compatible with `NA`

.

Effects are represented by the first fifteen capital letters.

Used to generate the model formulas for `combine_predictors`

.

### Author(s)

Ludvig Renbo Olsen, r-pkgs@ludvigolsen.dk

[Package

*cvms* version 1.3.3

Index]