From 69a6c8df295960cdf1a38763416c8b02139dd9ce Mon Sep 17 00:00:00 2001
From: lluni <llunii+gitea@pm.me>
Date: Sun, 22 May 2022 01:42:41 +0200
Subject: [PATCH] Added MAE loss function

---
 .idea/workspace.xml              |  2 +-
 src/main/java/LossFunctions.java | 20 ++++++++++++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/.idea/workspace.xml b/.idea/workspace.xml
index 1e481d5..c932344 100644
--- a/.idea/workspace.xml
+++ b/.idea/workspace.xml
@@ -6,7 +6,7 @@
   <component name="ChangeListManager">
     <list default="true" id="75a8c215-b746-4a4d-aa16-f3223c12b1ed" name="Changes" comment="Commented out not yet working code">
       <change beforePath="$PROJECT_DIR$/.idea/workspace.xml" beforeDir="false" afterPath="$PROJECT_DIR$/.idea/workspace.xml" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/src/main/java/FCLayer.java" beforeDir="false" afterPath="$PROJECT_DIR$/src/main/java/FCLayer.java" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/src/main/java/LossFunctions.java" beforeDir="false" afterPath="$PROJECT_DIR$/src/main/java/LossFunctions.java" afterDir="false" />
     </list>
     <option name="SHOW_DIALOG" value="false" />
     <option name="HIGHLIGHT_CONFLICTS" value="true" />
diff --git a/src/main/java/LossFunctions.java b/src/main/java/LossFunctions.java
index c59193d..26d735a 100644
--- a/src/main/java/LossFunctions.java
+++ b/src/main/java/LossFunctions.java
@@ -14,4 +14,24 @@ public class LossFunctions {
     public static SimpleMatrix MSEPrime(SimpleMatrix y_true, SimpleMatrix y_pred) {
         return y_true.minus(y_pred).divide((double) y_true.getNumElements()/2);
     }
+
+    public static double MAE(SimpleMatrix y_true, SimpleMatrix y_pred) {
+        double sum = 0;
+        for (int i = 0; i < y_true.getNumElements(); i++) {
+            sum += Math.abs(y_true.get(i) - y_pred.get(i));
+        }
+        return sum / y_true.getNumElements();
+    }
+
+    public static SimpleMatrix MAEPrime(SimpleMatrix y_true, SimpleMatrix y_pred) {
+        SimpleMatrix result = new SimpleMatrix(y_true);
+        for (int i = 0; i < result.getNumElements(); i++) {
+            if (y_true.get(i) < y_pred.get(i)) {
+                result.set(i, 1d);
+            } else {
+                result.set(i, -1d);
+            }
+        }
+        return result;
+    }
 }