dynamo-core: Additions to tf utilities

 - Added gaussian and min-max scalers for TF data sets
 - Added `dtfpipe` a workflows/pipes library for working with TF data

Author: mandar2812

build.sbt

@@ -9,7 +9,7 @@ packageSummary := "Scala Library/REPL for Machine Learning Research"
 
 packageDescription := "DynaML is a Scala environment for conducting research and education in Machine Learning. DynaML comes packaged with a powerful library of classes for various predictive models and a Scala REPL where one can not only build custom models but also play around with data work-flows. It can also be used as an educational/research tool for data analysis."
 
-val mainVersion = "v1.5.2"
+val mainVersion = "v1.5.3-beta.1"
 
 val dataDirectory = settingKey[File]("The directory holding the data files for running example scripts")
 

dynaml-core/src/main/scala-2.11/io/github/mandar2812/dynaml/tensorflow/package.scala

@@ -21,6 +21,8 @@ package io.github.mandar2812.dynaml
 import java.nio.ByteBuffer
 
 import io.github.mandar2812.dynaml.probability._
+import io.github.mandar2812.dynaml.pipes._
+import io.github.mandar2812.dynaml.tensorflow.utils._
 import org.platanios.tensorflow.api._
 import org.platanios.tensorflow.api.core.Shape
 import org.platanios.tensorflow.api.ops.NN.SamePadding
@@ -287,8 +289,11 @@ package object tensorflow {
   }
 
   /**
+    * <h4>DynaML Neural Net Building Blocks</h4>
     *
-    *
+    * The [[dtflearn]] object contains components
+    * that can be used to create custom neural architectures,
+    * from basic building blocks.
     * */
   object dtflearn {
 
@@ -397,4 +402,62 @@ package object tensorflow {
 
   }
 
+  /**
+    * <h4>DynaML Tensorflow Pipes</h4>
+    *
+    * The [[dtfpipe]] contains workflows/pipelines to simplify working
+    * with tensorflow data sets and models.
+    * */
+  object dtfpipe {
+
+    val gaussian_standardization: DataPipe2[Tensor, Tensor, ((Tensor, Tensor), (GaussianScalerTF, GaussianScalerTF))] =
+      DataPipe2((features: Tensor, labels: Tensor) => {
+
+        val (features_mean, labels_mean) = (features.mean(axes = 0), labels.mean(axes = 0))
+
+        val n_data = features.shape(0).scalar.asInstanceOf[Int].toDouble
+
+        val (features_sd, labels_sd) = (
+          features.subtract(features_mean).square.mean(axes = 0).multiply(n_data/(n_data - 1d)).sqrt,
+          labels.subtract(labels_mean).square.mean(axes = 0).multiply(n_data/(n_data - 1d)).sqrt
+        )
+
+        val (features_scaler, labels_scaler) = (
+          GaussianScalerTF(features_mean, features_sd),
+          GaussianScalerTF(labels_mean, labels_sd)
+        )
+
+        val (features_scaled, labels_scaled) = (
+          features_scaler(features),
+          labels_scaler(labels)
+        )
+
+        ((features_scaled, labels_scaled), (features_scaler, labels_scaler))
+      })
+
+    val minmax_standardization: DataPipe2[Tensor, Tensor, ((Tensor, Tensor), (MinMaxScalerTF, MinMaxScalerTF))] =
+      DataPipe2((features: Tensor, labels: Tensor) => {
+
+        val (features_min, labels_min) = (features.min(axes = 0), labels.min(axes = 0))
+
+        val (features_max, labels_max) = (
+          features.max(axes = 0),
+          labels.max(axes = 0)
+        )
+
+        val (features_scaler, labels_scaler) = (
+          MinMaxScalerTF(features_min, features_max),
+          MinMaxScalerTF(labels_min, labels_max)
+        )
+
+        val (features_scaled, labels_scaled) = (
+          features_scaler(features),
+          labels_scaler(labels)
+        )
+
+        ((features_scaled, labels_scaled), (features_scaler, labels_scaler))
+      })
+
+  }
+
 }

dynaml-core/src/main/scala-2.11/io/github/mandar2812/dynaml/tensorflow/utils/GaussianScalerTF.scala

@@ -0,0 +1,39 @@
+/*
+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.
+* */
+package io.github.mandar2812.dynaml.tensorflow.utils
+
+import org.platanios.tensorflow.api._
+import _root_.io.github.mandar2812.dynaml.pipes._
+
+/**
+  * Scales attributes of a vector pattern using the sample mean and variance of
+  * each dimension. This assumes that there is no covariance between the data
+  * dimensions.
+  *
+  * @param mean Sample mean of the data
+  * @param sigma Sample variance of each data dimension
+  * @author mandar2812 date: 07/03/2018.
+  *
+  * */
+case class GaussianScalerTF(mean: Tensor, sigma: Tensor) extends TFScaler {
+
+  override val i: Scaler[Tensor] = Scaler((xc: Tensor) => xc.multiply(sigma).add(mean))
+
+  override def run(data: Tensor): Tensor = data.subtract(mean).divide(sigma)
+}

dynaml-core/src/main/scala-2.11/io/github/mandar2812/dynaml/tensorflow/utils/MinMaxScalerTF.scala

@@ -0,0 +1,41 @@
+/*
+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.
+* */
+package io.github.mandar2812.dynaml.tensorflow.utils
+
+import org.platanios.tensorflow.api._
+import _root_.io.github.mandar2812.dynaml.pipes._
+
+/**
+  * Scales attributes of a vector pattern using the sample minimum and maximum of
+  * each dimension.
+  *
+  * @param min Sample minimum of the data
+  * @param max Sample maximum of each data dimension
+  * @author mandar2812 date: 07/03/2018.
+  *
+  * */
+case class MinMaxScalerTF(min: Tensor, max: Tensor) extends TFScaler {
+
+  val delta: Tensor = max.subtract(min)
+
+  override val i: Scaler[Tensor] = Scaler((xc: Tensor) => xc.multiply(delta).add(min))
+
+  override def run(data: Tensor): Tensor = data.subtract(min).divide(delta)
+
+}

dynaml-core/src/main/scala-2.11/io/github/mandar2812/dynaml/tensorflow/utils/TFScaler.scala

@@ -0,0 +1,24 @@
+/*
+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.
+* */
+package io.github.mandar2812.dynaml.tensorflow.utils
+
+import io.github.mandar2812.dynaml.pipes.ReversibleScaler
+import org.platanios.tensorflow.api.Tensor
+
+abstract class TFScaler extends ReversibleScaler[Tensor]

dynaml-core/src/main/scala-2.11/io/github/mandar2812/dynaml/tensorflow/TensorBasis.scala renamed to dynaml-core/src/main/scala-2.11/io/github/mandar2812/dynaml/tensorflow/utils/TensorBasis.scala

@@ -16,7 +16,7 @@ KIND, either express or implied.  See the License for the
 specific language governing permissions and limitations
 under the License.
 * */
-package io.github.mandar2812.dynaml.tensorflow
+package io.github.mandar2812.dynaml.tensorflow.utils
 
 import io.github.mandar2812.dynaml.pipes.DataPipe
 import org.apache.spark.annotation.Experimental