mindspore.nn.polynomial_decay_lr
- mindspore.nn.polynomial_decay_lr(learning_rate, end_learning_rate, total_step, step_per_epoch, decay_epoch, power, update_decay_epoch=False)[source]
Calculate learning rate base on polynomial decay function.
For the i-th step, the formula of computing decayed_learning_rate[i] is:
\[decayed\_learning\_rate[i] = (learning\_rate - end\_learning\_rate) * (1 - tmp\_epoch / tmp\_decay\_epoch)^{power} + end\_learning\_rate\]Where:
\[tmp\_epoch = min(current\_epoch, decay\_epoch)\]\[current\_epoch=floor(\frac{i}{step\_per\_epoch})\]\[tmp\_decay\_epoch = decay\_epoch\]If update_decay_epoch is true, update the value of tmp_decay_epoch every epoch. The formula is:
\[tmp\_decay\_epoch = decay\_epoch * ceil(current\_epoch / decay\_epoch)\]- Parameters
learning_rate (float) – The initial value of learning rate.
end_learning_rate (float) – The end value of learning rate.
total_step (int) – The total number of steps.
step_per_epoch (int) – The number of steps in per epoch.
decay_epoch (int) – A value used to calculate decayed learning rate.
power (float) – A value used to calculate decayed learning rate. This parameter must be greater than 0.
update_decay_epoch (bool) – If true, update decay_epoch. Default: False.
- Returns
list[float]. The size of list is total_step.
Examples
>>> learning_rate = 0.1 >>> end_learning_rate = 0.01 >>> total_step = 6 >>> step_per_epoch = 2 >>> decay_epoch = 2 >>> power = 0.5 >>> r = polynomial_decay_lr(learning_rate, end_learning_rate, total_step, step_per_epoch, decay_epoch, power) >>> print(r) [0.1, 0.1, 0.07363961030678928, 0.07363961030678928, 0.01, 0.01]