The metric how to get values of symbol network, in terms of variable name or Symbol name? How they interact of outputs of mx.symbol.Group?


How to understand their relationship? It always confused me. Because, if I change some codes in metric or output of mx.symbol.Group, loss always will be changed. Any advice will be appreciated! thank you.


It is not clear what you are trying to ask. Could you please provide more information on what you are trying to do along with some code snippet? Thanks!


thanks for your reply. My question is:

In the update function, I do not know what labels and preds include? If I want to use symbol ‘loss’ in the symbol network, how to transmit the symbol ‘loss’ to metric? And what are the functions of self.sum_metric and self.num_inst? Any advice will be appreciated. Thank you very much.

class AccMetric(mx.metric.EvalMetric):
def init(self):

super(AccMetric, self).init(

def update(self, labels, preds):

    self.sum_metric += (pred_label.flat == label.flat).sum()
    self.num_inst += len(pred_label.flat)