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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.

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

More information on how parsnip is used for modeling is at


  mode = "classification",
  regularization_method = NULL,
  engine = "MASS"



A single character string for the type of model. The only possible value for this model is "classification".


A character string for the type of regularized estimation. Possible values are: "diagonal", "shrink_cov", and "shrink_mean" (sparsediscrim engine only).


A single character string specifying what computational engine to use for fitting.


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.