scheduler-param {dials}

Parameters for neural network learning rate schedulers These parameters are used for constructing neural network models.

Description

Parameters for neural network learning rate schedulers These parameters are used for constructing neural network models.

Usage

rate_initial(range = c(-3, -1), trans = transform_log10())

rate_largest(range = c(-1, -1/2), trans = transform_log10())

rate_reduction(range = c(1/5, 1), trans = NULL)

rate_steps(range = c(2, 10), trans = NULL)

rate_step_size(range = c(2, 20), trans = NULL)

rate_decay(range = c(0, 2), trans = NULL)

rate_schedule(values = values_scheduler)

values_scheduler

Arguments

range

A two-element vector holding the defaults for the smallest and largest possible values, respectively. If a transformation is specified, these values should be in the transformed units.

trans

A trans object from the scales package, such as scales::transform_log10() or scales::transform_reciprocal(). If not provided, the default is used which matches the units used in range. If no transformation, NULL.

values

A character string of possible values. See values_scheduler in examples below.

Format

An object of class character of length 5.

Details

These parameters are often used with neural networks via parsnip::mlp(engine = "brulee").

The details for how the brulee schedulers change the rates:

• schedule_decay_time(): rate(epoch) = initial/(1 + decay \times epoch)

• schedule_decay_expo(): rate(epoch) = initial\exp(-decay \times epoch)

• schedule_step(): rate(epoch) = initial \times reduction^{floor(epoch / steps)}

• schedule_cyclic(): cycle = floor( 1 + (epoch / 2 / step size) ), x = abs( ( epoch / step size ) - ( 2 * cycle) + 1 ), and rate(epoch) = initial + ( largest - initial ) * \max( 0, 1 - x)