From d130c7cce11b487b566028b70ec8c3a87a5041aa Mon Sep 17 00:00:00 2001
From: lluni <llunii+gitea@pm.me>
Date: Sat, 4 Feb 2023 17:56:30 +0100
Subject: [PATCH] Layers don't need to store the forward pass output

---
 src/layers/activation_layer.rs | 10 ++++++----
 src/layers/fc_layer.rs         | 10 ++++++----
 2 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/src/layers/activation_layer.rs b/src/layers/activation_layer.rs
index 8a271ed..47a0c03 100644
--- a/src/layers/activation_layer.rs
+++ b/src/layers/activation_layer.rs
@@ -5,7 +5,7 @@ use crate::functions::activation_functions::*;
 
 pub struct ActivationLayer {
     input: Array1<f64>,
-    output: Array1<f64>,
+    // output: Array1<f64>,
     activation: fn(&Array1<f64>) -> Array1<f64>,
     activation_prime: fn(&Array1<f64>) -> Array1<f64>,
 }
@@ -15,7 +15,7 @@ impl ActivationLayer {
         let (activation, activation_prime) = parse_type(activation_fn);
         ActivationLayer {
             input: arr1(&[]),
-            output: arr1(&[]),
+            // output: arr1(&[]),
             activation,
             activation_prime,
         }
@@ -25,8 +25,10 @@ impl ActivationLayer {
 impl Layer for ActivationLayer {
     fn forward_pass(&mut self, input: ArrayView1<f64>) -> Array1<f64> {
         self.input = input.to_owned();
-        self.output = (self.activation)(&self.input);
-        self.output.clone()
+        // output isn't needed elsewhere
+        // self.output = (self.activation)(&self.input);
+        // self.output.clone()
+        (self.activation)(&self.input)
     }
 
     fn backward_pass(&mut self, output_error: ArrayView1<f64>, _learning_rate: f64) -> Array1<f64> {
diff --git a/src/layers/fc_layer.rs b/src/layers/fc_layer.rs
index 1aa0202..af0330d 100644
--- a/src/layers/fc_layer.rs
+++ b/src/layers/fc_layer.rs
@@ -40,7 +40,7 @@ pub struct FCLayer {
     weight_initializer: Initializer,
     bias_initializer: Initializer,
     input: Array1<f64>,
-    output: Array1<f64>,
+    // output: Array1<f64>,
     weights: Array2<f64>,
     biases: Array1<f64>,
 }
@@ -57,7 +57,7 @@ impl FCLayer {
             weight_initializer,
             bias_initializer,
             input: arr1(&[]),
-            output: arr1(&[]),
+            // output: arr1(&[]),
             weights: arr2(&[[]]),
             biases: arr1(&[]),
         }
@@ -77,8 +77,10 @@ impl Layer for FCLayer {
         }
 
         self.input = input.to_owned();
-        self.output = self.input.dot(&self.weights) + &self.biases;
-        self.output.clone()
+        // output isn't needed elsewhere
+        // self.output = self.input.dot(&self.weights) + &self.biases;
+        // self.output.clone()
+        self.input.dot(&self.weights) + &self.biases
     }
 
     fn backward_pass(&mut self, output_error: ArrayView1<f64>, learning_rate: f64) -> Array1<f64> {