diff --git a/examples/example_sine.rs b/examples/example_sine.rs
index 87ef3d7..e968bcf 100644
--- a/examples/example_sine.rs
+++ b/examples/example_sine.rs
@@ -49,7 +49,7 @@ fn main() {
         Initializer::GaussianWFactor(0.0, 1.0, 0.1),
     )));
     network.add_layer(Box::new(ActivationLayer::new(
-        activation_functions::Type::Gelu,
+        activation_functions::Type::LeakyRelu,
     )));
     network.add_layer(Box::new(FCLayer::new(
         8,
@@ -57,7 +57,7 @@ fn main() {
         Initializer::GaussianWFactor(0.0, 1.0, 0.1),
     )));
     network.add_layer(Box::new(ActivationLayer::new(
-        activation_functions::Type::Gelu,
+        activation_functions::Type::LeakyRelu,
     )));
     network.add_layer(Box::new(FCLayer::new(
         1,
diff --git a/src/functions/activation_functions.rs b/src/functions/activation_functions.rs
index 0ab9c8b..c65f728 100644
--- a/src/functions/activation_functions.rs
+++ b/src/functions/activation_functions.rs
@@ -7,7 +7,6 @@ pub enum Type {
     Tanh,
     Relu,
     LeakyRelu,
-    Gelu,
 }
 
 type ActFuncTuple = (
@@ -22,7 +21,6 @@ pub fn parse_type(t: Type) -> ActFuncTuple {
         Type::Tanh => (tanh, tanh_prime),
         Type::Relu => (relu, relu_prime),
         Type::LeakyRelu => (leaky_relu, leaky_relu_prime),
-        Type::Gelu => (gelu, gelu_prime),
     }
 }
 
@@ -31,7 +29,11 @@ pub fn identity(matrix: &Array1<f64>) -> Array1<f64> {
 }
 
 pub fn identity_prime(matrix: &Array1<f64>) -> Array1<f64> {
-    Array1::ones(matrix.raw_dim())
+    let mut result = matrix.clone();
+    for x in result.iter_mut() {
+        *x = 1.0;
+    }
+    result
 }
 
 fn sigmoid(x: f64) -> f64 {
@@ -46,7 +48,7 @@ pub fn logistic(matrix: &Array1<f64>) -> Array1<f64> {
 
 pub fn logistic_prime(matrix: &Array1<f64>) -> Array1<f64> {
     let mut result = matrix.clone();
-    result.mapv_inplace(|x| sigmoid(x) * (1.0 - sigmoid(x)));
+    result.mapv_inplace(|x| sigmoid(x * (1.0 - sigmoid(x))));
     result
 }
 
@@ -85,15 +87,3 @@ pub fn leaky_relu_prime(matrix: &Array1<f64>) -> Array1<f64> {
     result.mapv_inplace(|x| if x <= 0.0 { 0.001 } else { 1.0 });
     result
 }
-
-pub fn gelu(matrix: &Array1<f64>) -> Array1<f64> {
-    let mut result = matrix.clone();
-    result.mapv_inplace(|x| x * sigmoid(1.702 * x));
-    result
-}
-
-pub fn gelu_prime(matrix: &Array1<f64>) -> Array1<f64> {
-    let mut result = matrix.clone();
-    result.mapv_inplace(|x| sigmoid(1.702 * x) * (1.0 + 1.702 * (1.0 - sigmoid(1.702 * x))));
-    result
-}