[MXNET-1333] Estimator and Fit API (#14629)

* [MXNet-1334][Fit API]base class for estimator and eventhandler (#14346)

* base class for estimator and eventhandler

* add license

* add event handlers

* fix pylint

* improve arg check

* fix pylint

* add unit tests

* Fixed issue where the estimator was printing beyond the dataset size … (#14464)

* Fixed issue where the estimator was printing beyond the dataset size for the last batch

* Added comments

* Nudge to CI

* [MXNet-1349][Fit API]Add validation support and unit tests for fit() API (#14442)

* added estimator unittests

* add more tests for estimator

* added validation logic

* added error handlers, unittests

* improve val stats

* fix pylint

* fix pylint

* update unit test

* fix tests

* fix tests

* updated metrics, val logic

* trigger ci

* trigger ci

* update metric, batch_fn error handler

* update context logic, add default metric

* [MXNet-1340][Fit API]Update train stats (#14494)

* add train history

* update history

* update test

* avoid calling empty methods

* remove train history object

* fix pylint

* add unit test

* fix test

* update categorize handlers

* [MXNet-1375][Fit API]Added RNN integration test for fit() API (#14547)

* Added RNN integration test for fit() API

* Addressed review comments: change in JenkinFile, tmp directory, ctx with condense if/else, renamed imports

* CPU test doesn't require nvidiadocker container

* Modified the structure by removing the redundant code

* [MXNet-1343][Fit API]Add CNN integration test for fit() API (#14405)

* added cnn intg tests for fit api

* updated cnn intg tests

* added functions for nightly test

* updated runtime_function

* updated intg tests

* updated init, datapath, refs

* added validation data

* update cpu test

* refactor code

* updated context

* [MXNET-1344, 1346][FIT API] Retrieve Batch size and Logging verbose support for Gluon fit() API (#14587)

* Retrieve Batch size and Logging verbose support for Gluon fit() API

* NIT changes

* Addressed review comments: shifted the batch size code to a separate method, sentence correction

* Modified unittest

* removed redundant parameter

* Resolve CI test failure

* only support DataLoader for now, future PRs will include DataIter to DataLoader converter

* Get the number of samples from shape attribute instead of length due to low space complexity

* Simplified batch size retrieval code

* removed batch_size parameter from fit() method and fixed the tests

* Verbose exception handling

* Assigning constant to a verbose

* Modified exception message

* Resolved undefined class reference

* Addressed review comments: Modified verbose level names, docs, variable names

* Update estimator.py

* move estimator to contrib (#14633)

* move to gluon contrib (#14635)

* [Fit API] improve event handlers (#14685)

* improve event handlers

* update tests

* passing weakref of estimator

* fix unit test

* fix test

* fix pylint

* fix test

* fix pylint

* move default metric logic

* combine nightly tests

* [MXNET-1396][Fit-API] Update default handler logic (#14765)

* move to nightly for binaries

* update default handler

* fix pylint

* trigger ci

* trigger ci

* [Fit API] update estimator (#14849)

* address comments

* add comment

* check available context

* fix bug

* change cpu check

* [Fit-API] Adress PR comments (#14885)

* address comments

* update checkpoint

* test symbol save

* address comments

* add resume

* update doc and resume checkpoint

* update docs

* trigger ci

* trigger ci

ci/docker/runtime_functions.sh

@@ -1350,6 +1350,16 @@ nightly_scala_demo_test_cpu() {
     bash bin/run_im.sh
 }
 
+nightly_estimator() {
+    set -ex
+    cd /work/mxnet/tests/nightly/estimator
+    export PYTHONPATH=/work/mxnet/python/
+    python test_estimator_cnn.py --type gpu
+    python test_sentiment_rnn.py --type gpu
+    python test_estimator_cnn.py --type cpu
+    python test_sentiment_rnn.py --type cpu
+}
+
 # Deploy
 
 deploy_docs() {

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

@@ -0,0 +1,21 @@
+# 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.
+
+# pylint: disable=wildcard-import
+"""Gluon Estimator Module"""
+from .estimator import *
+from .event_handler import *