diff --git a/.idea/workspace.xml b/.idea/workspace.xml
index c932344..c8d666d 100644
--- a/.idea/workspace.xml
+++ b/.idea/workspace.xml
@@ -4,9 +4,8 @@
     <option name="autoReloadType" value="SELECTIVE" />
   </component>
   <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/LossFunctions.java" beforeDir="false" afterPath="$PROJECT_DIR$/src/main/java/LossFunctions.java" afterDir="false" />
+    <list default="true" id="75a8c215-b746-4a4d-aa16-f3223c12b1ed" name="Changes" comment="Added MAE loss function">
+      <change beforePath="$PROJECT_DIR$/src/main/java/ActivationFunctions.java" beforeDir="false" afterPath="$PROJECT_DIR$/src/main/java/ActivationFunctions.java" afterDir="false" />
     </list>
     <option name="SHOW_DIALOG" value="false" />
     <option name="HIGHLIGHT_CONFLICTS" value="true" />
@@ -98,7 +97,14 @@
       <option name="project" value="LOCAL" />
       <updated>1653168727186</updated>
     </task>
-    <option name="localTasksCounter" value="2" />
+    <task id="LOCAL-00002" summary="Added MAE loss function">
+      <created>1653176561735</created>
+      <option name="number" value="00002" />
+      <option name="presentableId" value="LOCAL-00002" />
+      <option name="project" value="LOCAL" />
+      <updated>1653176561735</updated>
+    </task>
+    <option name="localTasksCounter" value="3" />
     <servers />
   </component>
   <component name="Vcs.Log.Tabs.Properties">
@@ -115,7 +121,8 @@
   <component name="VcsManagerConfiguration">
     <MESSAGE value="Initial commit" />
     <MESSAGE value="Commented out not yet working code" />
-    <option name="LAST_COMMIT_MESSAGE" value="Commented out not yet working code" />
+    <MESSAGE value="Added MAE loss function" />
+    <option name="LAST_COMMIT_MESSAGE" value="Added MAE loss function" />
   </component>
   <component name="com.intellij.coverage.CoverageDataManagerImpl">
     <SUITE FILE_PATH="coverage/JavaNN$ExampleXOR.ic" NAME="ExampleXOR Coverage Results" MODIFIED="1653174521293" SOURCE_PROVIDER="com.intellij.coverage.DefaultCoverageFileProvider" RUNNER="idea" COVERAGE_BY_TEST_ENABLED="false" COVERAGE_TRACING_ENABLED="false" />
diff --git a/src/main/java/ActivationFunctions.java b/src/main/java/ActivationFunctions.java
index b073eb0..ae5e7c8 100644
--- a/src/main/java/ActivationFunctions.java
+++ b/src/main/java/ActivationFunctions.java
@@ -36,4 +36,20 @@ public class ActivationFunctions {
     private static double sigma(double value) {
         return 1 / (1 + Math.exp(-value));
     }
+
+    public static SimpleMatrix ReLu(SimpleMatrix A) {
+        SimpleMatrix B = new SimpleMatrix(A);
+        for (int i = 0; i < A.getNumElements(); i++) {
+            B.set(i, Math.max(0, A.get(i)));
+        }
+        return B;
+    }
+
+    public static SimpleMatrix ReLuPrime(SimpleMatrix A) {
+        SimpleMatrix B = new SimpleMatrix(A);
+        for (int i = 0; i < A.getNumElements(); i++) {
+            B.set(i, A.get(i) < 0 ? 0 : 1);
+        }
+        return B;
+    }
 }