Added bias learning rate and weight decay multipliers to bn_ layers

dlib/dnn/layers.h

@@ -666,6 +666,8 @@ namespace dlib
             running_stats_window_size(window_size),
             learning_rate_multiplier(1),
             weight_decay_multiplier(0),
+            bias_learning_rate_multiplier(1),
+            bias_weight_decay_multiplier(1),
             eps(eps_)
         {}
 
@@ -680,6 +682,11 @@ namespace dlib
         void set_learning_rate_multiplier(double val) { learning_rate_multiplier = val; }
         void set_weight_decay_multiplier(double val)  { weight_decay_multiplier  = val; }
 
+        double get_bias_learning_rate_multiplier () const  { return bias_learning_rate_multiplier; }
+        double get_bias_weight_decay_multiplier () const   { return bias_weight_decay_multiplier; }
+        void set_bias_learning_rate_multiplier(double val) { bias_learning_rate_multiplier = val; }
+        void set_bias_weight_decay_multiplier(double val)  { bias_weight_decay_multiplier  = val; }
+
 
         template <typename SUBNET>
         void setup (const SUBNET& sub)
@@ -765,6 +772,8 @@ namespace dlib
             serialize(item.running_stats_window_size, out);
             serialize(item.learning_rate_multiplier, out);
             serialize(item.weight_decay_multiplier, out);
+            serialize(item.bias_learning_rate_multiplier, out);
+            serialize(item.bias_weight_decay_multiplier, out);
             serialize(item.eps, out);
         }
 
@@ -812,6 +821,8 @@ namespace dlib
             {
                 deserialize(item.learning_rate_multiplier, in);
                 deserialize(item.weight_decay_multiplier, in);
+                deserialize(item.bias_learning_rate_multiplier, in);
+                deserialize(item.bias_weight_decay_multiplier, in);
                 deserialize(item.eps, in);
             }
             else
@@ -834,6 +845,8 @@ namespace dlib
             out << " eps="<<item.eps;
             out << " learning_rate_mult="<<item.learning_rate_multiplier;
             out << " weight_decay_mult="<<item.weight_decay_multiplier;
+            out << " bias_learning_rate_mult="<<item.bias_learning_rate_multiplier;
+            out << " bias_weight_decay_mult="<<item.bias_weight_decay_multiplier;
             return out;
         }
 
@@ -849,6 +862,8 @@ namespace dlib
         unsigned long running_stats_window_size;
         double learning_rate_multiplier;
         double weight_decay_multiplier;
+        double bias_learning_rate_multiplier;
+        double bias_weight_decay_multiplier;
         double eps;
     };
 

dlib/dnn/layers_abstract.h

@@ -859,6 +859,8 @@ namespace dlib
                 - #get_running_stats_window_size()      == 1000
                 - #get_learning_rate_multiplier()       == 1
                 - #get_weight_decay_multiplier()        == 0
+                - #get_bias_learning_rate_multiplier()  == 1
+                - #get_bias_weight_decay_multiplier()   == 1
                 - #get_eps() == tt::DEFAULT_BATCH_NORM_EPS
         !*/
 
@@ -874,6 +876,8 @@ namespace dlib
                 - #get_running_stats_window_size()     == window_size
                 - #get_learning_rate_multiplier()      == 1
                 - #get_weight_decay_multiplier()       == 0
+                - #get_bias_learning_rate_multiplier() == 1
+                - #get_bias_weight_decay_multiplier()  == 1
                 - #get_eps() == eps
         !*/
 
@@ -953,6 +957,44 @@ namespace dlib
                 - #get_weight_decay_multiplier() == val
         !*/
 
+        double get_bias_learning_rate_multiplier(
+        ) const; 
+        /*!
+            ensures
+                - returns a multiplier number.  The interpretation is that this object is
+                  requesting that the learning rate used to optimize its bias parameters be
+                  multiplied by get_learning_rate_multiplier()*get_bias_learning_rate_multiplier().
+        !*/
+
+        double get_bias_weight_decay_multiplier(
+        ) const; 
+        /*!
+            ensures
+                - returns a multiplier number.  The interpretation is that this object is
+                  requesting that the weight decay used to optimize its bias parameters be
+                  multiplied by get_weight_decay_multiplier()*get_bias_weight_decay_multiplier().
+        !*/
+
+        void set_bias_learning_rate_multiplier(
+            double val
+        ); 
+        /*!
+            requires
+                - val >= 0
+            ensures
+                - #get_bias_learning_rate_multiplier() == val
+        !*/
+
+        void set_bias_weight_decay_multiplier(
+            double val
+        ); 
+        /*!
+            requires
+                - val >= 0
+            ensures
+                - #get_bias_weight_decay_multiplier() == val
+        !*/
+
         template <typename SUBNET> void setup (const SUBNET& sub);
         template <typename SUBNET> void forward(const SUBNET& sub, resizable_tensor& output);
         template <typename SUBNET> void backward(const tensor& gradient_input, SUBNET& sub, tensor& params_grad);

dlib/dnn/solvers.h

@@ -89,6 +89,17 @@ namespace dlib
             return v;
         }
 
+        template < layer_mode mode >
+        const tensor& operator() (
+            const float learning_rate,
+            const bn_<mode>& l,
+            const tensor& params_grad
+        )
+        {
+            update_considering_bias(learning_rate, l, params_grad, params_grad.size()/2);
+            return v;
+        }
+
         friend void serialize(const sgd& item, std::ostream& out)
         {
             serialize("sgd2", out);
@@ -244,6 +255,17 @@ namespace dlib
             return s;
         }
 
+        template < layer_mode mode >
+        const tensor& operator() (
+            const float learning_rate,
+            const bn_<mode>& l,
+            const tensor& params_grad
+        )
+        {
+            update_considering_bias(learning_rate, l, params_grad, params_grad.size()/2);
+            return s;
+        }
+
 
         friend void serialize(const adam& item, std::ostream& out)
         {