class_docstr: Exponential learning rate decay with warmup
  [0, warmup_epoch): linear warmup
  [warmup_epoch, epochs): Exponential decay
  Args:
      lr(float): initial learning rate
      step_each_epoch(int): steps each epoch
      decay_epochs(float): decay epochs
      decay_rate(float): decay rate
      warmup_epoch(int): epoch num of warmup
class_docstr_tok: ["Exponential","learning","rate","decay","with","warmup","[","0",",","warmup_epoch",")",":","linear","warmup","[","warmup_epoch",",","epochs",")",":","Exponential","decay","Args",":","lr","(","float",")",":","initial","learning","rate","step_each_epoch","(","int",")",":","steps","each","epoch","decay_epochs","(","float",")",":","decay","epochs","decay_rate","(","float",")",":","decay","rate","warmup_epoch","(","int",")",":","epoch","num","of","warmup"]
code: def __init__(
      self,
      lr,
      step_each_epoch,
      decay_epochs=2.4,
      decay_rate=0.97,
      warmup_epoch=5,
      **kwargs,
  ):
      warmup_step = warmup_epoch * step_each_epoch
      start_lr = 0.0
      end_lr = lr
      lr_sch = ExponentialDecay(lr, decay_rate)
  
      super(ExponentialWarmup, self).__init__(
          learning_rate=lr_sch,
          warmup_steps=warmup_step,
          start_lr=start_lr,
          end_lr=end_lr,
      )
  
      # NOTE: hac method to update exponential lr scheduler
      self.update_specified = True
      self.update_start_step = warmup_step
      self.update_step_interval = int(decay_epochs * step_each_epoch)
      self.step_each_epoch = step_each_epoch
  
imports: import sys
  import math
  from paddle.optimizer.lr import LinearWarmup
  from paddle.optimizer.lr import PiecewiseDecay
  from paddle.optimizer.lr import CosineAnnealingDecay
  from paddle.optimizer.lr import ExponentialDecay
  import paddle
  import paddle.regularizer
  from copy import deepcopy
label_desc: Use image node_id 1 to create a new ExponentialWarmup object from inherited base classes: LinearWarmup with example: obj = ExponentialWarmup(lr, step_each_epoch, decay_epochs, decay_rate, warmup_epoch)