♻️ Split NeuraTrainableLayerBase into ~ and NeuraTrainableLayerEval

src/gradient_solver/backprop.rs

@@ -1,9 +1,6 @@
 use num::ToPrimitive;
 
-use crate::{
-    derivable::NeuraLoss, layer::*,
-    network::*,
-};
+use crate::{derivable::NeuraLoss, layer::*, network::*};
 
 use super::*;
 
@@ -83,11 +80,9 @@ impl<
     fn map_epsilon<From, To, Gradient, Cb: Fn(From) -> To>(
         &self,
         rec_opt_output: Self::Output<From, Gradient>,
-        callback: Cb
+        callback: Cb,
     ) -> Self::Output<To, Gradient> {
-        (
-            callback(rec_opt_output.0), rec_opt_output.1
-        )
+        (callback(rec_opt_output.0), rec_opt_output.1)
     }
 }
 
@@ -95,30 +90,38 @@ trait BackpropRecurse<Input, Network, Gradient> {
     fn recurse(&self, network: &Network, input: &Input) -> (Input, Gradient);
 }
 
-impl<Input, Loss: NeuraLoss<Input>> BackpropRecurse<Input, (), ()> for (&NeuraBackprop<Loss>, &Loss::Target) {
+impl<Input, Loss: NeuraLoss<Input>> BackpropRecurse<Input, (), ()>
+    for (&NeuraBackprop<Loss>, &Loss::Target)
+{
     fn recurse(&self, _network: &(), input: &Input) -> (Input, ()) {
         (self.0.loss.nabla(self.1, input), ())
     }
 }
 
 impl<
-    Input: Clone,
-    Network: NeuraNetworkRec + NeuraNetwork<Input> + NeuraTrainableLayerBase<Input>,
-    Loss,
-    Target
-> BackpropRecurse<Input, Network, Network::Gradient> for (&NeuraBackprop<Loss>, &Target)
+        Input: Clone,
+        Network: NeuraNetworkRec + NeuraNetwork<Input> + NeuraTrainableLayerEval<Input>,
+        Loss,
+        Target,
+    > BackpropRecurse<Input, Network, Network::Gradient> for (&NeuraBackprop<Loss>, &Target)
 where
     // Verify that we can traverse recursively
-    for<'a> (&'a NeuraBackprop<Loss>, &'a Target): BackpropRecurse<Network::NodeOutput, Network::NextNode, <Network::NextNode as NeuraTrainableLayerBase<Network::NodeOutput>>::Gradient>,
+    for<'a> (&'a NeuraBackprop<Loss>, &'a Target): BackpropRecurse<
+        Network::NodeOutput,
+        Network::NextNode,
+        <Network::NextNode as NeuraTrainableLayerBase>::Gradient,
+    >,
     // Verify that the current layer implements the right traits
-    Network::Layer: NeuraTrainableLayerSelf<Network::LayerInput> + NeuraTrainableLayerBackprop<Network::LayerInput>,
+    Network::Layer: NeuraTrainableLayerSelf<Network::LayerInput>
+        + NeuraTrainableLayerBackprop<Network::LayerInput>,
     // Verify that the layer output can be cloned
     <Network::Layer as NeuraLayer<Network::LayerInput>>::Output: Clone,
-    Network::NextNode: NeuraTrainableLayerBase<Network::NodeOutput>,
+    Network::NextNode: NeuraTrainableLayerEval<Network::NodeOutput>,
 {
     fn recurse(&self, network: &Network, input: &Input) -> (Input, Network::Gradient) {
         let layer_input = network.map_input(input);
-        let (layer_output, layer_intermediary) = network.get_layer().eval_training(layer_input.as_ref());
+        let (layer_output, layer_intermediary) =
+            network.get_layer().eval_training(layer_input.as_ref());
         let output = network.map_output(input, &layer_output);
 
         let (epsilon_in, gradient_rec) = self.recurse(network.get_next(), output.as_ref());

src/gradient_solver/forward_forward.rs

@@ -138,7 +138,7 @@ impl<
     fn map_epsilon<From, To, Gradient, Cb: Fn(From) -> To>(
         &self,
         rec_opt_output: Self::Output<From, Gradient>,
-        _callback: Cb
+        _callback: Cb,
     ) -> Self::Output<To, Gradient> {
         rec_opt_output
     }

src/gradient_solver/mod.rs

@@ -5,7 +5,7 @@ mod forward_forward;
 pub use forward_forward::NeuraForwardForward;
 
 use crate::{
-    layer::NeuraTrainableLayerBase,
+    layer::{NeuraTrainableLayerBase, NeuraTrainableLayerEval},
     network::{NeuraOldTrainableNetwork, NeuraOldTrainableNetworkBase},
 };
 
@@ -17,7 +17,7 @@ pub trait NeuraGradientSolverFinal<LayerOutput>: NeuraGradientSolverBase {
     fn eval_final(&self, output: LayerOutput) -> Self::Output<LayerOutput, ()>;
 }
 
-pub trait NeuraGradientSolverTransient<Input, Layer: NeuraTrainableLayerBase<Input>>:
+pub trait NeuraGradientSolverTransient<Input, Layer: NeuraTrainableLayerEval<Input>>:
     NeuraGradientSolverBase
 {
     fn eval_layer<NetworkGradient, RecGradient>(
@@ -33,7 +33,7 @@ pub trait NeuraGradientSolverTransient<Input, Layer: NeuraTrainableLayerBase<Inp
     fn map_epsilon<From, To, Gradient, Cb: Fn(From) -> To>(
         &self,
         rec_opt_output: Self::Output<From, Gradient>,
-        callback: Cb
+        callback: Cb,
     ) -> Self::Output<To, Gradient>;
 }
 

src/layer/dense.rs

@@ -175,17 +175,9 @@ impl<
         F: Float + std::fmt::Debug + 'static + std::ops::AddAssign + std::ops::MulAssign,
         Act: NeuraDerivable<F>,
         Reg: NeuraDerivable<F>,
-    > NeuraTrainableLayerBase<DVector<F>> for NeuraDenseLayer<F, Act, Reg>
+    > NeuraTrainableLayerBase for NeuraDenseLayer<F, Act, Reg>
 {
     type Gradient = (DMatrix<F>, DVector<F>);
-    type IntermediaryRepr = DVector<F>; // pre-activation values
-
-    fn eval_training(&self, input: &DVector<F>) -> (Self::Output, Self::IntermediaryRepr) {
-        let evaluated = &self.weights * input + &self.bias;
-        let output = evaluated.map(|x| self.activation.eval(x));
-
-        (output, evaluated)
-    }
 
     fn default_gradient(&self) -> Self::Gradient {
         (
@@ -200,6 +192,22 @@ impl<
     }
 }
 
+impl<
+        F: Float + std::fmt::Debug + 'static + std::ops::AddAssign + std::ops::MulAssign,
+        Act: NeuraDerivable<F>,
+        Reg: NeuraDerivable<F>,
+    > NeuraTrainableLayerEval<DVector<F>> for NeuraDenseLayer<F, Act, Reg>
+{
+    type IntermediaryRepr = DVector<F>; // pre-activation values
+
+    fn eval_training(&self, input: &DVector<F>) -> (Self::Output, Self::IntermediaryRepr) {
+        let evaluated = &self.weights * input + &self.bias;
+        let output = evaluated.map(|x| self.activation.eval(x));
+
+        (output, evaluated)
+    }
+}
+
 impl<
         F: Float + std::fmt::Debug + 'static + std::ops::AddAssign + std::ops::MulAssign,
         Act: NeuraDerivable<F>,

src/layer/dropout.rs

@@ -63,13 +63,8 @@ impl<R: Rng, F: Float> NeuraLayer<DVector<F>> for NeuraDropoutLayer<R> {
     }
 }
 
-impl<R: Rng, F: Float> NeuraTrainableLayerBase<DVector<F>> for NeuraDropoutLayer<R> {
+impl<R: Rng> NeuraTrainableLayerBase for NeuraDropoutLayer<R> {
     type Gradient = ();
-    type IntermediaryRepr = ();
-
-    fn eval_training(&self, input: &DVector<F>) -> (Self::Output, Self::IntermediaryRepr) {
-        (self.eval(input), ())
-    }
 
     fn default_gradient(&self) -> Self::Gradient {
         ()
@@ -103,6 +98,14 @@ impl<R: Rng, F: Float> NeuraTrainableLayerBase<DVector<F>> for NeuraDropoutLayer
     }
 }
 
+impl<R: Rng, F: Float> NeuraTrainableLayerEval<DVector<F>> for NeuraDropoutLayer<R> {
+    type IntermediaryRepr = ();
+
+    fn eval_training(&self, input: &DVector<F>) -> (Self::Output, Self::IntermediaryRepr) {
+        (self.eval(input), ())
+    }
+}
+
 impl<R: Rng, F: Float> NeuraTrainableLayerSelf<DVector<F>> for NeuraDropoutLayer<R> {
     fn regularize_layer(&self) -> Self::Gradient {
         ()
@@ -144,9 +147,7 @@ mod test {
             .unwrap();
 
         for _ in 0..100 {
-            <NeuraDropoutLayer<_> as NeuraTrainableLayerBase<DVector<f64>>>::prepare_layer(
-                &mut layer, true,
-            );
+            layer.prepare_layer(true);
             assert!(layer.multiplier.is_finite());
             assert!(!layer.multiplier.is_nan());
         }

src/layer/lock.rs

@@ -32,11 +32,8 @@ impl<Input, Layer: NeuraLayer<Input>> NeuraLayer<Input> for NeuraLockLayer<Layer
     }
 }
 
-impl<Input, Layer: NeuraTrainableLayerBase<Input>> NeuraTrainableLayerBase<Input>
-    for NeuraLockLayer<Layer>
-{
+impl<Layer: NeuraTrainableLayerBase> NeuraTrainableLayerBase for NeuraLockLayer<Layer> {
     type Gradient = ();
-    type IntermediaryRepr = Layer::IntermediaryRepr;
 
     fn default_gradient(&self) -> Self::Gradient {
         ()
@@ -45,13 +42,19 @@ impl<Input, Layer: NeuraTrainableLayerBase<Input>> NeuraTrainableLayerBase<Input
     fn apply_gradient(&mut self, _gradient: &Self::Gradient) {
         // Noop
     }
+}
+
+impl<Input, Layer: NeuraTrainableLayerEval<Input>> NeuraTrainableLayerEval<Input>
+    for NeuraLockLayer<Layer>
+{
+    type IntermediaryRepr = Layer::IntermediaryRepr;
 
     fn eval_training(&self, input: &Input) -> (Self::Output, Self::IntermediaryRepr) {
         self.layer.eval_training(input)
     }
 }
 
-impl<Input, Layer: NeuraTrainableLayerBase<Input>> NeuraTrainableLayerSelf<Input>
+impl<Input, Layer: NeuraTrainableLayerEval<Input>> NeuraTrainableLayerSelf<Input>
     for NeuraLockLayer<Layer>
 {
     fn regularize_layer(&self) -> Self::Gradient {

src/layer/mod.rs

@@ -59,30 +59,32 @@ pub trait NeuraPartialLayer {
     fn construct(self, input_shape: NeuraShape) -> Result<Self::Constructed, Self::Err>;
 }
 
-pub trait NeuraTrainableLayerBase<Input>: NeuraLayer<Input> {
+pub trait NeuraTrainableLayerBase {
     /// The representation of the layer gradient as a vector space
     type Gradient: NeuraVectorSpace;
 
-    /// An intermediary object type to be passed to the various training methods
-    type IntermediaryRepr;
-
     fn default_gradient(&self) -> Self::Gradient;
 
     /// Applies `δW_l` to the weights of the layer
     fn apply_gradient(&mut self, gradient: &Self::Gradient);
 
-    // TODO: move this into another trait
-    fn eval_training(&self, input: &Input) -> (Self::Output, Self::IntermediaryRepr);
-
     /// Arbitrary computation that can be executed at the start of an epoch
     #[allow(unused_variables)]
     #[inline(always)]
     fn prepare_layer(&mut self, is_training: bool) {}
 }
 
+pub trait NeuraTrainableLayerEval<Input>: NeuraTrainableLayerBase + NeuraLayer<Input> {
+    /// An intermediary object type to be passed to the various training methods
+    type IntermediaryRepr;
+
+    // TODO: move this into another trait
+    fn eval_training(&self, input: &Input) -> (Self::Output, Self::IntermediaryRepr);
+}
+
 /// Contains methods relative to a layer's ability to compute its own weights gradients,
 /// given the derivative of the output variables.
-pub trait NeuraTrainableLayerSelf<Input>: NeuraTrainableLayerBase<Input> {
+pub trait NeuraTrainableLayerSelf<Input>: NeuraTrainableLayerEval<Input> {
     /// Computes the regularization
     fn regularize_layer(&self) -> Self::Gradient;
 
@@ -117,7 +119,7 @@ pub trait NeuraTrainableLayerSelf<Input>: NeuraTrainableLayerBase<Input> {
 //     }
 // }
 
-pub trait NeuraTrainableLayerBackprop<Input>: NeuraTrainableLayerBase<Input> {
+pub trait NeuraTrainableLayerBackprop<Input>: NeuraTrainableLayerEval<Input> {
     /// Computes the backpropagation term and the derivative of the internal weights,
     /// using the `input` vector outputted by the previous layer and the backpropagation term `epsilon` of the next layer.
     ///
@@ -137,9 +139,8 @@ pub trait NeuraTrainableLayerBackprop<Input>: NeuraTrainableLayerBase<Input> {
     ) -> Input;
 }
 
-impl<Input: Clone> NeuraTrainableLayerBase<Input> for () {
+impl NeuraTrainableLayerBase for () {
     type Gradient = ();
-    type IntermediaryRepr = ();
 
     #[inline(always)]
     fn default_gradient(&self) -> Self::Gradient {
@@ -150,7 +151,12 @@ impl<Input: Clone> NeuraTrainableLayerBase<Input> for () {
     fn apply_gradient(&mut self, _gradient: &Self::Gradient) {
         // Noop
     }
+}
+
+impl<Input: Clone> NeuraTrainableLayerEval<Input> for () {
+    type IntermediaryRepr = ();
 
+    #[inline(always)]
     fn eval_training(&self, input: &Input) -> (Self::Output, Self::IntermediaryRepr) {
         (self.eval(input), ())
     }

src/layer/normalize.rs

@@ -56,9 +56,8 @@ impl<F: Float + Scalar> NeuraLayer<DVector<F>> for NeuraNormalizeLayer {
     }
 }
 
-impl<F: Float + Scalar + NumAssignOps> NeuraTrainableLayerBase<DVector<F>> for NeuraNormalizeLayer {
+impl NeuraTrainableLayerBase for NeuraNormalizeLayer {
     type Gradient = ();
-    type IntermediaryRepr = (DMatrix<F>, F); // Partial jacobian matrix (without the kroenecker term) and stddev
 
     fn default_gradient(&self) -> Self::Gradient {
         ()
@@ -67,6 +66,10 @@ impl<F: Float + Scalar + NumAssignOps> NeuraTrainableLayerBase<DVector<F>> for N
     fn apply_gradient(&mut self, _gradient: &Self::Gradient) {
         // Noop
     }
+}
+
+impl<F: Float + Scalar + NumAssignOps> NeuraTrainableLayerEval<DVector<F>> for NeuraNormalizeLayer {
+    type IntermediaryRepr = (DMatrix<F>, F); // Partial jacobian matrix (without the kroenecker term) and stddev
 
     fn eval_training(&self, input: &DVector<F>) -> (Self::Output, Self::IntermediaryRepr) {
         let (mean, variance, len) = mean_variance(input);

src/layer/softmax.rs

@@ -56,9 +56,8 @@ impl NeuraPartialLayer for NeuraSoftmaxLayer {
     }
 }
 
-impl<F: Float + Scalar + NumAssignOps> NeuraTrainableLayerBase<DVector<F>> for NeuraSoftmaxLayer {
+impl NeuraTrainableLayerBase for NeuraSoftmaxLayer {
     type Gradient = ();
-    type IntermediaryRepr = Self::Output; // Result of self.eval
 
     fn default_gradient(&self) -> Self::Gradient {
         ()
@@ -67,6 +66,10 @@ impl<F: Float + Scalar + NumAssignOps> NeuraTrainableLayerBase<DVector<F>> for N
     fn apply_gradient(&mut self, _gradient: &Self::Gradient) {
         // Noop
     }
+}
+
+impl<F: Float + Scalar + NumAssignOps> NeuraTrainableLayerEval<DVector<F>> for NeuraSoftmaxLayer {
+    type IntermediaryRepr = Self::Output; // Result of self.eval
 
     fn eval_training(&self, input: &DVector<F>) -> (Self::Output, Self::IntermediaryRepr) {
         let res = self.eval(input);

src/network/mod.rs

@@ -1,5 +1,7 @@
 use crate::{
-    algebra::NeuraVectorSpace, gradient_solver::{NeuraGradientSolverBase, NeuraGradientSolverFinal}, layer::NeuraLayer,
+    algebra::NeuraVectorSpace,
+    gradient_solver::{NeuraGradientSolverBase, NeuraGradientSolverFinal},
+    layer::NeuraLayer,
 };
 
 // pub mod residual;

src/network/sequential/layer_impl.rs

@@ -1,5 +1,5 @@
 use super::*;
-use crate::layer::NeuraTrainableLayerBackprop;
+use crate::layer::{NeuraTrainableLayerBackprop, NeuraTrainableLayerEval};
 
 impl<Input, Layer: NeuraLayer<Input>, ChildNetwork: NeuraLayer<Layer::Output>> NeuraLayer<Input>
     for NeuraSequential<Layer, ChildNetwork>
@@ -11,14 +11,10 @@ impl<Input, Layer: NeuraLayer<Input>, ChildNetwork: NeuraLayer<Layer::Output>> N
     }
 }
 
-impl<
-        Input,
-        Layer: NeuraTrainableLayerBase<Input>,
-        ChildNetwork: NeuraTrainableLayerBase<Layer::Output>,
-    > NeuraTrainableLayerBase<Input> for NeuraSequential<Layer, ChildNetwork>
+impl<Layer: NeuraTrainableLayerBase, ChildNetwork: NeuraTrainableLayerBase> NeuraTrainableLayerBase
+    for NeuraSequential<Layer, ChildNetwork>
 {
     type Gradient = (Layer::Gradient, Box<ChildNetwork::Gradient>);
-    type IntermediaryRepr = (Layer::IntermediaryRepr, Box<ChildNetwork::IntermediaryRepr>);
 
     fn default_gradient(&self) -> Self::Gradient {
         (
@@ -27,16 +23,6 @@ impl<
         )
     }
 
-    fn eval_training(&self, input: &Input) -> (Self::Output, Self::IntermediaryRepr) {
-        let (layer_output, layer_intermediary) = self.layer.eval_training(input);
-        let (child_output, child_intermediary) = self.child_network.eval_training(&layer_output);
-
-        (
-            child_output,
-            (layer_intermediary, Box::new(child_intermediary)),
-        )
-    }
-
     fn prepare_layer(&mut self, is_training: bool) {
         self.layer.prepare_layer(is_training);
         self.child_network.prepare_layer(is_training);
@@ -48,6 +34,25 @@ impl<
     }
 }
 
+impl<
+        Input,
+        Layer: NeuraTrainableLayerEval<Input>,
+        ChildNetwork: NeuraTrainableLayerEval<Layer::Output>,
+    > NeuraTrainableLayerEval<Input> for NeuraSequential<Layer, ChildNetwork>
+{
+    type IntermediaryRepr = (Layer::IntermediaryRepr, Box<ChildNetwork::IntermediaryRepr>);
+
+    fn eval_training(&self, input: &Input) -> (Self::Output, Self::IntermediaryRepr) {
+        let (layer_output, layer_intermediary) = self.layer.eval_training(input);
+        let (child_output, child_intermediary) = self.child_network.eval_training(&layer_output);
+
+        (
+            child_output,
+            (layer_intermediary, Box::new(child_intermediary)),
+        )
+    }
+}
+
 impl<
         Input,
         Layer: NeuraTrainableLayerSelf<Input>,

src/network/sequential/mod.rs

@@ -1,8 +1,9 @@
 use super::{NeuraOldTrainableNetwork, NeuraOldTrainableNetworkBase};
 use crate::{
-    gradient_solver::{NeuraGradientSolverTransient},
+    gradient_solver::NeuraGradientSolverTransient,
     layer::{
-        NeuraLayer, NeuraPartialLayer, NeuraShape, NeuraTrainableLayerBase, NeuraTrainableLayerSelf,
+        NeuraLayer, NeuraPartialLayer, NeuraShape, NeuraTrainableLayerBase,
+        NeuraTrainableLayerEval, NeuraTrainableLayerSelf,
     },
 };
 
@@ -81,7 +82,7 @@ impl<Layer, ChildNetwork> NeuraSequential<Layer, ChildNetwork> {
 
 impl<
         Input,
-        Layer: NeuraTrainableLayerBase<Input> + NeuraTrainableLayerSelf<Input>,
+        Layer: NeuraTrainableLayerEval<Input> + NeuraTrainableLayerSelf<Input>,
         ChildNetwork: NeuraOldTrainableNetworkBase<Layer::Output>,
     > NeuraOldTrainableNetworkBase<Input> for NeuraSequential<Layer, ChildNetwork>
 {
@@ -141,7 +142,7 @@ impl<Input: Clone> NeuraOldTrainableNetworkBase<Input> for () {
 
 impl<
         Input,
-        Layer: NeuraTrainableLayerBase<Input> + NeuraTrainableLayerSelf<Input>,
+        Layer: NeuraTrainableLayerEval<Input> + NeuraTrainableLayerSelf<Input>,
         Optimizer: NeuraGradientSolverTransient<Input, Layer>,
         ChildNetwork: NeuraOldTrainableNetworkBase<Layer::Output>,
     > NeuraOldTrainableNetwork<Input, Optimizer> for NeuraSequential<Layer, ChildNetwork>

src/network/traits.rs

@@ -14,7 +14,7 @@ pub trait NeuraNetworkBase {
 pub trait NeuraNetwork<NodeInput: Clone>: NeuraNetworkBase
 where
     Self::Layer: NeuraLayer<Self::LayerInput>,
-    <Self::Layer as NeuraLayer<Self::LayerInput>>::Output: Clone
+    <Self::Layer as NeuraLayer<Self::LayerInput>>::Output: Clone,
 {
     /// The type of the input to `Self::Layer`
     type LayerInput: Clone;
@@ -25,12 +25,25 @@ where
     /// Maps the input of network node to the enclosed layer
     fn map_input<'a>(&'_ self, input: &'a NodeInput) -> Cow<'a, Self::LayerInput>;
     /// Maps the output of the enclosed layer to the output of the network node
-    fn map_output<'a>(&'_ self, input: &'_ NodeInput, layer_output: &'a <Self::Layer as NeuraLayer<Self::LayerInput>>::Output) -> Cow<'a, Self::NodeOutput>;
+    fn map_output<'a>(
+        &'_ self,
+        input: &'_ NodeInput,
+        layer_output: &'a <Self::Layer as NeuraLayer<Self::LayerInput>>::Output,
+    ) -> Cow<'a, Self::NodeOutput>;
 
     /// Maps a gradient in the format of the node's output into the format of the enclosed layer's output
-    fn map_gradient_in<'a>(&'_ self, input: &'_ NodeInput, gradient_in: &'a Self::NodeOutput) -> Cow<'a, <Self::Layer as NeuraLayer<Self::LayerInput>>::Output>;
+    fn map_gradient_in<'a>(
+        &'_ self,
+        input: &'_ NodeInput,
+        gradient_in: &'a Self::NodeOutput,
+    ) -> Cow<'a, <Self::Layer as NeuraLayer<Self::LayerInput>>::Output>;
     /// Maps a gradient in the format of the enclosed layer's input into the format of the node's input
-    fn map_gradient_out<'a>(&'_ self, input: &'_ NodeInput, gradient_in: &'_ Self::NodeOutput, gradient_out: &'a Self::LayerInput) -> Cow<'a, NodeInput>;
+    fn map_gradient_out<'a>(
+        &'_ self,
+        input: &'_ NodeInput,
+        gradient_in: &'_ Self::NodeOutput,
+        gradient_out: &'a Self::LayerInput,
+    ) -> Cow<'a, NodeInput>;
 }
 
 pub trait NeuraNetworkRec: NeuraNetworkBase {
@@ -39,6 +52,4 @@ pub trait NeuraNetworkRec: NeuraNetworkBase {
     type NextNode;
 
     fn get_next(&self) -> &Self::NextNode;
-
-
 }