R: Quadratic discriminant analysis

discrim_quad {parsnip}

R Documentation

Quadratic discriminant analysis

Description

discrim_quad() defines a model that estimates a multivariate distribution for the predictors separately for the data in each class (usually Gaussian with separate covariance matrices). Bayes' theorem is used to compute the probability of each class, given the predictor values. This function can fit classification models.

There are different ways to fit this model, and the method of estimation is chosen by setting the model engine. The engine-specific pages for this model are listed below.

MASS¹²
sparsediscrim²

¹ The default engine. ² Requires a parsnip extension package.

More information on how parsnip is used for modeling is at https://www.tidymodels.org/.

Usage

discrim_quad(
  mode = "classification",
  regularization_method = NULL,
  engine = "MASS"
)

Arguments

`mode`	A single character string for the type of model. The only possible value for this model is "classification".
`regularization_method`	A character string for the type of regularized estimation. Possible values are: "`diagonal`", "`shrink_cov`", and "`shrink_mean`" (`sparsediscrim` engine only).
`engine`	A single character string specifying what computational engine to use for fitting.

Details

This function only defines what type of model is being fit. Once an engine is specified, the method to fit the model is also defined. See set_engine() for more on setting the engine, including how to set engine arguments.

The model is not trained or fit until the fit() function is used with the data.

Each of the arguments in this function other than mode and engine are captured as quosures. To pass values programmatically, use the injection operator like so:

value <- 1
discrim_quad(argument = !!value)

References