Merge branch 'mine' into 'tf2'

MINE: Mutual Information Neural Estimation

See merge request !86

bob/learn/tensorflow/losses/__init__.py

@@ -18,6 +18,6 @@ def __appropriate__(*args):
 
 __appropriate__(
     CenterLoss,
-    CenterLossLayer,
+    CenterLossLayer
 )
 __all__ = [_ for _ in dir() if not _.startswith("_")]

bob/learn/tensorflow/metrics/__init__.py

-from .embedding_accuracy import EmbeddingAccuracy
+from .embedding_accuracy import EmbeddingAccuracy, predict_using_tensors
 
 # gets sphinx autodoc done right - don't remove it
 def __appropriate__(*args):

bob/learn/tensorflow/models/__init__.py

 from .alexnet import AlexNet_simplified
 from .densenet import DenseNet
+from .mine import MineModel
 
 # gets sphinx autodoc done right - don't remove it
 def __appropriate__(*args):
@@ -20,5 +21,6 @@ def __appropriate__(*args):
 __appropriate__(
     AlexNet_simplified,
     DenseNet,
+    MineModel
 )
 __all__ = [_ for _ in dir() if not _.startswith("_")]

bob/learn/tensorflow/models/mine.py

+"""
+Implements the MINE loss from the paper:
+
+Mutual Information Neural Estimation (https://arxiv.org/pdf/1801.04062.pdf)
+
+"""
+
+import tensorflow as tf
+
+class MineModel(tf.keras.Model):
+    """
+
+    Parameters
+    **********
+
+      is_mine_f: bool
+         If true, will implement MINE-F (equation 6), otherwise will implement equation 5
+    """
+
+    def __init__(self, is_mine_f=False, name="MINE", units=10, **kwargs):
+        super().__init__(name=name, **kwargs)
+        self.units = units
+        self.is_mine_f = is_mine_f
+        
+        self.transformer_x = tf.keras.layers.Dense(self.units)
+        self.transformer_z = tf.keras.layers.Dense(self.units)
+        self.transformer_xz = tf.keras.layers.Dense(self.units)
+        self.transformer_output = tf.keras.layers.Dense(1)
+
+    def call(self, inputs):
+        def compute(x, z):
+            h1_x = self.transformer_x(x)
+            h1_z = self.transformer_z(z)
+            h1 = tf.keras.layers.ReLU()(h1_x + h1_z)
+            h2 = self.transformer_output(tf.keras.layers.ReLU()(self.transformer_xz(h1)))
+
+            return h2
+
+        def compute_lower_bound(x, z):
+            t_xz = compute(x,z)
+            z_shuffle = tf.random.shuffle(z)
+            t_x_z = compute(x, z_shuffle)
+
+            if self.is_mine_f:
+                lb = -(
+                    tf.reduce_mean(t_xz, axis=0)
+                    - tf.reduce_mean(tf.math.exp(t_x_z-1))
+                )
+            else:
+                lb = -(
+                    tf.reduce_mean(t_xz, axis=0)
+                    - tf.math.log(tf.reduce_mean(tf.math.exp(t_x_z)))
+                )
+
+            self.add_loss(lb)
+            return -lb
+
+        x = inputs[0]
+        z = inputs[1]
+
+        return compute_lower_bound(x, z)
+
+
+    def get_config(self):
+        config = super().get_config()
+        config.update({"units": self.units})
+        return config
+

bob/learn/tensorflow/tests/test_mine.py

+import numpy as np
+import tensorflow as tf
+from bob.learn.tensorflow.models import MineModel
+
+def run_mine(is_mine_f):
+    np.random.seed(10)
+    N = 20000
+    d = 1
+    EPOCHS = 100
+
+    X = np.sign(np.random.normal(0.,1.,[N, d]))
+    Z = X + np.random.normal(0.,np.sqrt(0.2),[N, d])
+
+
+    from sklearn.feature_selection import mutual_info_regression
+    mi_numerical = mutual_info_regression(X.reshape(-1, 1), Z.ravel())[0]
+
+    model = MineModel(is_mine_f=is_mine_f)
+    model.compile(optimizer=tf.keras.optimizers.Adam(learning_rate=0.01))
+
+    callback = model.fit(
+        x=[X, Z], epochs=EPOCHS, verbose=1, batch_size=100
+    )
+    mine = -np.array(callback.history["loss"])[-1]
+
+    np.allclose(mine,mi_numerical, atol=0.01)
+
+
+def test_mine():
+    run_mine(False)
+
+def test_mine_f():
+    run_mine(True)
\ No newline at end of file

conda/meta.yaml

@@ -23,17 +23,7 @@ requirements:
     - bob.extension
     - bob.io.base
     - bob.io.image
-    - bob.learn.activation
-    - bob.learn.em
-    - bob.learn.linear
-    - bob.ip.base
-    - bob.math
     - bob.measure
-    - bob.sp
-    - bob.db.mnist
-    - bob.db.atnt
-    - bob.bio.base
-    - bob.ip.color
     - click {{ click }}
     - click-plugins {{ click_plugins }}
   run:

requirements.txt

@@ -2,16 +2,7 @@ setuptools
 bob.extension
 bob.io.base
 bob.io.image
-bob.learn.activation
-bob.learn.em
-bob.learn.linear
-bob.ip.base
-bob.math
 bob.measure
-bob.sp
-bob.db.mnist
-bob.db.atnt
-gridtk
 numpy
-scipy
 click >= 7
+scipy
\ No newline at end of file