utils_train.py

import numpy as np
class LossLogger:
    def __init__(self):
        self.losses  = ["loss", "val_loss"]
        self.loss_history = {k:[] for k in self.losses}
    def append_loss(self, loss_):
        self.loss_history['loss'].append(loss_)
        
    def append_val_loss(self, val_loss_):
        self.loss_history['val_loss'].append(val_loss_)
    
    def print(self):
        loss, val_loss = [self.loss_history[vv] for vv in self.losses]
        print("loss: %2.3f, val_loss %2.3f"%(loss[-1], val_loss[-1]))

class EarlyStopping:
    def __init__(self, patience, loss_handle):
        self.patience = patience
        self.loss_handle = loss_handle
    
    def on_epoch_end(self, epoch):
        break_ = False
        
        if len(self.loss_handle) > 1:
            if np.all(np.min(self.loss_handle[-self.patience:]) > self.min_val):
                print("*** Early stopping. ***")
                break_ = True
                
            else:
                self.min_val = np.min(self.loss_handle)
        else:
            
            self.min_val = self.loss_handle[-1]
        
        return break_
    
class LRScheduler:
    def __init__(self, opt_object, base_lr = 0.001,epoch_decay = 50, decay_rate = 0.95, burnin_epochs = 10):
        self.opt_object = opt_object
        self.opt_object.lr.assign(base_lr)
        if burnin_epochs >0:
            self.opt_object.lr.assign(0)

        self.burnin_epochs = burnin_epochs
        self.base_lr = base_lr
        self.epoch_decay = epoch_decay
        self.decay_rate = decay_rate
        
    def on_epoch_end(self,epoch):
        if epoch <=self.burnin_epochs:
            new_lr = self.base_lr * (epoch / float(self.burnin_epochs))
            print("burn-in:  setting lr to %2.5f"%new_lr)
            self.opt_object.lr.assign(new_lr)

        if epoch >= self.epoch_decay:
            lr = self.opt_object.lr.numpy()
            new_lr = lr * self.decay_rate
            print("lr_decay: setting lr to %2.5f"%new_lr)
            self.opt_object.lr.assign(new_lr)