These functions can be used to optimize engine-specific parameters of
`sda::sda()`

via `discrim::discrim_linear()`

.

shrinkage_correlation(range = c(0, 1), trans = NULL)
shrinkage_variance(range = c(0, 1), trans = NULL)
shrinkage_frequencies(range = c(0, 1), trans = NULL)
diagonal_covariance(values = c(TRUE, FALSE))

## Arguments

range |
A two-element vector holding the *defaults* for the smallest and
largest possible values, respectively. |

trans |
A `trans` object from the `scales` package, such as
`scales::log10_trans()` or `scales::reciprocal_trans()` . If not provided,
the default is used which matches the units used in `range` . If no
transformation, `NULL` . |

values |
A vector of possible values (TRUE or FALSE). |

## Value

For the functions, they return a function with classes "param" and
either "quant_param" or "qual_param".

## Details

These functions map to `sda::sda()`

arguments via:

`shrinkage_correlation()`

to `lambda`

`shrinkage_variance()`

to `lambda.var`

`shrinkage_frequencies()`

to `lambda.freqs`

`diagonal_covariance()`

to `diagonal`