Set up a basic README with a pointer to the dev summit colab.

PiperOrigin-RevId: 194273919

tensorflow/contrib/autograph/README.md

@@ -1,4 +1,117 @@
-# Autograph
+# AutoGraph
 
-A compiler for generating TensorFlow numeric and control flow ops from Python
-code.
+IMPORTANT: AutoGraph is pre-alpha, under active development. Expect rough edges and bugs, but if you try it, we appreciate early feedback!
+
+AutoGraph is a Python to TensorFlow compiler.
+
+With AutoGraph, you can write [Eager style](https://www.tensorflow.org/programmers_guide/eager) code in a concise manner, and run it as a TensorFlow graph. AutoGraph uses source code transformation and partial evaluation to generate Python code that builds an equivalent TensorFlow subgraph. The result is code that behaves like ops and can be freely combined with other TensorFlow ops.
+
+For example, this Python function:
+
+```
+def f(x):
+  if x < 0:
+    x = -x
+  return x
+```
+
+would be converted to this:
+
+```
+def graph_mode_f(x):
+  with tf.name_scope('f'):
+
+    def if_true():
+      with tf.name_scope('if_true'):
+        x_1, = x,
+        x_1 = tf.negative(x_1)
+        return x_1,
+
+    def if_false():
+      with tf.name_scope('if_false'):
+        x_1, = x,
+        return x_1,
+    x = ag__.utils.run_cond(tf.greater(x, 0), if_true, if_false)
+    return x
+```
+
+so you can use it like an op:
+
+```
+with tf.Graph().as_default():
+  x = tf.constant(-1.0)
+
+  converted_f = autograph.to_graph(f)
+  y = converted_f(x)
+
+  with tf.Session() as sess:
+    print(sess.run(y))
+    # Output: 1
+```
+
+# Getting started
+
+Use AutoGraph in one of the following ways, described below:
+
+ 1. Annotations (simpler)
+ 2. Functional API (more flexible)
+
+NOTE: You can find more examples in this [interactive notebook](https://colab.research.google.com/github/tensorflow/tensorflow/blob/master/tensorflow/contrib/autograph/examples/notebooks/dev_summit_2018_demo.ipynb).
+
+To get started, install the latest nightly TensorFlow build:
+
+```shell
+pip install -U tf-nightly
+```
+
+Then import the `autograph` module from `tf.contrib`:
+
+```
+from tensorflow.contrib import autograph as ag
+```
+
+## Using with annotations
+
+Annotating a function or class with `@convert` converts it in place:
+
+```
+@ag.convert()
+def f(x):
+  if x < 0:
+    x = -x
+  return x
+```
+
+... so that it always outputs TensorFlow code:
+
+```
+with tf.Graph().as_default():
+  x = tf.constant(-1)
+
+  y = f(x)
+
+  with tf.Session() as sess:
+    print(sess.run(y))
+    # Output: 1
+```
+
+## Using the functional API
+
+The functional API allows you to convert an existing function, class or object after it was defined:
+
+```
+converted_f = ag.to_graph(f)
+
+print(converted_f(tf.constant(-1)))
+# Output: Tensor
+
+print(f(-1))
+# Output: 1
+```
+
+You can use the functional API to inspect the generated code as well:
+
+```
+print(ag.to_code(f))
+# Output: <Python and TensorFlow code>
+```