fix composite metric case in handlers

Author: Sheng Zha

python/mxnet/gluon/contrib/estimator/estimator.py

@@ -24,6 +24,7 @@
 
 from .event_handler import MetricHandler, ValidationHandler, LoggingHandler, StoppingHandler
 from .event_handler import TrainBegin, EpochBegin, BatchBegin, BatchEnd, EpochEnd, TrainEnd
+from .utils import _check_metrics
 from ...data import DataLoader
 from ...loss import SoftmaxCrossEntropyLoss
 from ...loss import Loss as gluon_loss
@@ -68,7 +69,7 @@ def __init__(self, net,
 
         self.net = net
         self.loss = self._check_loss(loss)
-        self.train_metrics = self._check_metrics(metrics)
+        self.train_metrics = _check_metrics(metrics)
 
         self.context = self._check_context(context)
         self._initialize(initializer)
@@ -84,18 +85,6 @@ def _check_loss(self, loss):
                              "refer to gluon.loss.Loss:{}".format(loss))
         return loss
 
-    def _check_metrics(self, metrics):
-        if isinstance(metrics, CompositeEvalMetric):
-            metrics = metrics.metrics
-        elif isinstance(metrics, EvalMetric):
-            metrics = [metrics]
-        else:
-            metrics = metrics or []
-            if not all([isinstance(metric, EvalMetric) for metric in metrics]):
-                raise ValueError("metrics must be a Metric or a list of Metric, "
-                                 "refer to mxnet.metric.EvalMetric:{}".format(metrics))
-        return metrics
-
     def _check_context(self, context):
         # infer available context
         gpus = num_gpus()

python/mxnet/gluon/contrib/estimator/event_handler.py

@@ -26,8 +26,9 @@
 
 import numpy as np
 
-from ....metric import EvalMetric
+from ....metric import EvalMetric, CompositeEvalMetric
 from ....metric import Loss as metric_loss
+from .utils import _check_metrics
 
 __all__ = ['TrainBegin', 'TrainEnd', 'EpochBegin', 'EpochEnd', 'BatchBegin', 'BatchEnd',
            'StoppingHandler', 'MetricHandler', 'ValidationHandler',
@@ -118,7 +119,7 @@ class MetricHandler(EpochBegin, BatchEnd):
     """
 
     def __init__(self, train_metrics):
-        self.train_metrics = train_metrics or []
+        self.train_metrics = _check_metrics(train_metrics)
         # order to be called among all callbacks
         # metrics need to be calculated before other callbacks can access them
         self.priority = -np.Inf
@@ -173,7 +174,7 @@ def __init__(self,
         self.eval_fn = eval_fn
         self.epoch_period = epoch_period
         self.batch_period = batch_period
-        self.val_metrics = val_metrics
+        self.val_metrics = _check_metrics(val_metrics)
         self.current_batch = 0
         self.current_epoch = 0
         # order to be called among all callbacks
@@ -255,8 +256,8 @@ def __init__(self, file_name=None,
                              "E.g: LoggingHandler(verbose=LoggingHandler.LOG_PER_EPOCH)"
                              % verbose)
         self.verbose = verbose
-        self.train_metrics = train_metrics or []
-        self.val_metrics = val_metrics or []
+        self.train_metrics = _check_metrics(train_metrics)
+        self.val_metrics = _check_metrics(val_metrics)
         self.batch_index = 0
         self.current_epoch = 0
         self.processed_samples = 0
@@ -637,6 +638,9 @@ def __init__(self,
         if not isinstance(monitor, EvalMetric):
             raise ValueError("Please provide one of the metric objects as monitor, "
                              "You can create these objects using estimator.prepare_loss_and_metric()")
+        if isinstance(monitor, CompositeEvalMetric):
+            raise ValueError("CompositeEvalMetric is not supported for EarlyStoppingHandler, "
+                             "please specify a simple metric instead.")
         self.monitor = monitor
         self.baseline = baseline
         self.patience = patience

python/mxnet/gluon/contrib/estimator/utils.py

@@ -0,0 +1,34 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+# coding: utf-8
+# pylint: disable=wildcard-import, unused-variable
+"""Gluon Estimator Utility Functions"""
+
+from ....metric import EvalMetric, CompositeEvalMetric
+
+def _check_metrics(metrics):
+    if isinstance(metrics, CompositeEvalMetric):
+        metrics = [m for metric in metrics.metrics for m in _check_metrics(metric)]
+    elif isinstance(metrics, EvalMetric):
+        metrics = [metrics]
+    else:
+        metrics = metrics or []
+        if not all([isinstance(metric, EvalMetric) for metric in metrics]):
+            raise ValueError("metrics must be a Metric or a list of Metric, "
+                             "refer to mxnet.metric.EvalMetric:{}".format(metrics))
+    return metrics

tests/nightly/estimator/test_sentiment_rnn.py

@@ -191,10 +191,13 @@ def run(net, train_dataloader, test_dataloader, num_epochs, ctx, lr):
     # Define loss and evaluation metrics
     loss = gluon.loss.SoftmaxCrossEntropyLoss()
     metrics = mx.metric.CompositeEvalMetric()
-    metrics.add([mx.metric.Accuracy(), mx.metric.Loss()])
+    acc = mx.metric.Accuracy()
+    nested_metrics = mx.metric.CompositeEvalMetric()
+    metrics.add([acc, mx.metric.Loss()])
+    nested_metrics.add([metrics, mx.metric.Accuracy()])
 
     # Define estimator
-    est = estimator.Estimator(net=net, loss=loss, metrics=metrics,
+    est = estimator.Estimator(net=net, loss=loss, metrics=nested_metrics,
                               trainer=trainer, context=ctx)
     # Begin training
     est.fit(train_data=train_dataloader, val_data=test_dataloader,