def nll_loss(input, target, weight=None, size_average=True):
 return _functions.thnn.NLLLoss(size_average, weight=weight)(input, target)

def nll_loss ( input , target , weight = None , size_average = True ) : return _functions . thnn . NLLLoss ( size_average , weight = weight ) ( input , target )
the negative log likelihood loss .