Create CanonicalForm.summary() to print a statically-known type information.

This follows a similar convetion to tf.kersas.Model.summary(): https://www.tensorflow.org/api_docs/python/tf/keras/Model#summary

PiperOrigin-RevId: 273609432

docs/api_docs/python/tff/backends/mapreduce/CanonicalForm.md

@@ -10,6 +10,7 @@
 <meta itemprop="property" content="work"/>
 <meta itemprop="property" content="zero"/>
 <meta itemprop="property" content="__init__"/>
+<meta itemprop="property" content="summary"/>
 </div>
 
 # tff.backends.mapreduce.CanonicalForm
@@ -320,3 +321,21 @@ decorator/wrapper.
 <h3 id="work"><code>work</code></h3>
 
 <h3 id="zero"><code>zero</code></h3>
+
+## Methods
+
+<h3 id="summary"><code>summary</code></h3>
+
+<a target="_blank" href="http://github.com/tensorflow/federated/tree/master/tensorflow_federated/python/core/backends/mapreduce/canonical_form.py">View
+source</a>
+
+```python
+summary(print_fn=print)
+```
+
+Prints a string summary of the `CanonicalForm`.
+
+#### Arguments:
+
+*   <b>`print_fn`</b>: Print function to use. It will be called on each line of
+    the summary in order to capture the string summary.

tensorflow_federated/python/core/backends/mapreduce/BUILD

@@ -22,6 +22,14 @@ py_library(
     ],
 )
 
+py_test(
+    name = "canonical_form_test",
+    srcs = ["canonical_form_test.py"],
+    python_version = "PY3",
+    srcs_version = "PY3",
+    deps = [":test_utils"],
+)
+
 py_library(
     name = "canonical_form_utils",
     srcs = ["canonical_form_utils.py"],

tensorflow_federated/python/core/backends/mapreduce/canonical_form.py

@@ -415,3 +415,25 @@ class CanonicalForm(object):
   @property
   def update(self):
     return self._update
+
+  def summary(self, print_fn=print):
+    """Prints a string summary of the `CanonicalForm`.
+
+    Arguments:
+      print_fn: Print function to use. It will be called on each line of the
+        summary in order to capture the string summary.
+    """
+    computations = [
+        ('initialize', self.initialize),
+        ('prepare', self.prepare),
+        ('work', self.work),
+        ('zero', self.zero),
+        ('accumulate', self.accumulate),
+        ('merge', self.merge),
+        ('report', self.report),
+        ('update', self.initialize),
+    ]
+    for name, comp in computations:
+      # Add sufficient padding to align first column; len('initialize') == 10
+      print_fn('{:<10}: {}'.format(
+          name, comp.type_signature.compact_representation()))

tensorflow_federated/python/core/backends/mapreduce/canonical_form_test.py

+# Lint as: python2, python3
+# Copyright 2019, The TensorFlow Federated Authors.
+#
+# Licensed 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.
+
+import textwrap
+from absl.testing import absltest
+import tensorflow as tf
+
+from tensorflow_federated.python.core.backends.mapreduce import test_utils
+
+
+class CanonicalFormTest(absltest.TestCase):
+
+  def test_summary(self):
+    cf = test_utils.get_temperature_sensor_example()
+
+    class CapturePrint(object):
+
+      def __init__(self):
+        self.summary = ''
+
+      def __call__(self, msg):
+        self.summary += msg + '\n'
+
+    capture = CapturePrint()
+    cf.summary(print_fn=capture)
+    self.assertEqual(
+        capture.summary,
+        textwrap.dedent("""\
+    initialize: ( -> <num_rounds=int32>)
+    prepare   : (<num_rounds=int32> -> <max_temperature=float32>)
+    work      : (<float32*,<max_temperature=float32>> -> <<is_over=bool>,<num_readings=int32>>)
+    zero      : ( -> <num_total=int32,num_over=int32>)
+    accumulate: (<<num_total=int32,num_over=int32>,<is_over=bool>> -> <num_total=int32,num_over=int32>)
+    merge     : (<<num_total=int32,num_over=int32>,<num_total=int32,num_over=int32>> -> <num_total=int32,num_over=int32>)
+    report    : (<num_total=int32,num_over=int32> -> <ratio_over_threshold=float32>)
+    update    : ( -> <num_rounds=int32>)
+    """))
+
+
+if __name__ == '__main__':
+  tf.compat.v1.enable_v2_behavior()
+  absltest.main()

tensorflow_federated/tools/BUILD

+package(default_visibility = ["//visibility:private"])
+
+licenses(["notice"])
+
+filegroup(
+    name = "build_docs",
+    srcs = ["build_docs.py"],
+    tags = ["ignore_srcs"],
+)