Keras models support (#7)

* temp add

* fix tests

* update

* addback

* update

* fit iris test case

* follow comments

Author: typhoonzero

.travis.yml

@@ -12,7 +12,6 @@ language: python
 python:
 - 3.6
 - 3.7
-- 3.8-dev
 
 install:
 - python setup.py -q install

setup.py

@@ -22,6 +22,7 @@
 
 # What packages are required for this module to be executed?
 REQUIRED = [
+    'tensorflow==2.0.0-alpha0'
 ]
 SETUP_REQUIRED = [
     'pytest-runner'

sqlflow_models/__init__.py

@@ -1 +1,2 @@
 from ._version import __version__
+from .dnnclassifier import DNNClassifier

sqlflow_models/dnnclassifier.py

@@ -0,0 +1,42 @@
+import tensorflow as tf
+
+class DNNClassifier(tf.keras.Model):
+    def __init__(self, feature_columns, hidden_units=[10,10], n_classes=2):
+        """DNNClassifier
+        :param feature_columns: feature columns.
+        :type feature_columns: list[tf.feature_column].
+        :param hidden_units: number of hidden units.
+        :type hidden_units: list[int].
+        :param n_classes: List of hidden units per layer.
+        :type n_classes: int.
+        """
+        super(DNNClassifier, self).__init__()
+
+        # combines all the data as a dense tensor
+        self.feature_layer = tf.keras.layers.DenseFeatures(feature_columns)
+        self.hidden_layers = []
+        for hidden_unit in hidden_units:
+            self.hidden_layers.append(tf.keras.layers.Dense(hidden_unit))
+        self.prediction_layer = tf.keras.layers.Dense(n_classes, activation='softmax')
+
+    def call(self, inputs):
+        x = self.feature_layer(inputs)
+        for hidden_layer in self.hidden_layers:
+            x = hidden_layer(x)
+        return self.prediction_layer(x)
+
+    def default_optimizer(self):
+        """Default optimizer name. Used in model.compile."""
+        return tf.keras.optimizers.Adagrad(lr=0.1)
+
+    def default_loss(self):
+        """Default loss function. Used in model.compile."""
+        return 'sparse_categorical_crossentropy'
+
+    def default_training_epochs(self):
+        """Default training epochs. Used in model.fit."""
+        return 2
+
+    def prepare_prediction_column(self, prediction):
+        """Return the class label of highest probability."""
+        return prediction.argmax(axis=-1)

tests/base.py

@@ -0,0 +1,31 @@
+import unittest
+import tensorflow as tf
+
+def train_input_fn(features, labels, batch_size=32):
+    dataset = tf.data.Dataset.from_tensor_slices((dict(features), labels))
+    dataset = dataset.shuffle(1000).repeat().batch(batch_size)
+    return dataset
+
+def eval_input_fn(features, labels, batch_size=32):
+    dataset = tf.data.Dataset.from_tensor_slices((dict(features), labels))
+    dataset = dataset.batch(batch_size)
+    return dataset
+
+class BaseTestCases:
+    class BaseTest(object):
+        def setUp(self):
+            self.model, self.features, self.label = None, {}, None
+
+        def test_train_and_predict(self):
+            self.setUp()
+
+            self.model.compile(optimizer=self.model.default_optimizer(),
+                loss=self.model.default_loss(),
+                metrics=["accuracy"])
+            self.model.fit(train_input_fn(self.features, self.label),
+                epochs=self.model.default_training_epochs(),
+                steps_per_epoch=100, verbose=0)
+            loss, acc = self.model.evaluate(eval_input_fn(self.features, self.label))
+            print(loss, acc)
+            assert(loss < 10)
+            assert(acc > 0.3)

tests/test_dnnclassifier.py

@@ -0,0 +1,22 @@
+import sqlflow_models
+from .base import BaseTestCases
+
+import tensorflow as tf
+import unittest
+
+
+class TestDNNClassifier(BaseTestCases.BaseTest):
+    def setUp(self):
+        self.features = {"c1": [float(x) for x in range(100)],
+                         "c2": [float(x) for x in range(100)],
+                         "c3": [float(x) for x in range(100)],
+                         "c4": [float(x) for x in range(100)]}
+        self.label = [0 for _ in range(50)] + [1 for _ in range(50)]
+        feature_columns = [tf.feature_column.numeric_column(key) for key in
+                           self.features]
+        self.model = sqlflow_models.DNNClassifier(feature_columns=feature_columns)
+
+
+if __name__ == '__main__':
+    unittest.main()
+