diff --git a/examples/optim.rs b/examples/optim.rs
new file mode 100644
index 00000000..13964c05
--- /dev/null
+++ b/examples/optim.rs
@@ -0,0 +1,39 @@
+#[macro_use]
+extern crate peroxide;
+use peroxide::fuga::*;
+
+fn main() {
+    // To prepare noise
+    let normal = Normal(0f64, 0.1f64);
+    let normal2 = Normal(0f64, 100f64);
+
+    // Noise to domain
+    let mut x = seq(0., 99., 1f64);
+    x = zip_with(|a, b| (a + b).abs(), &x, &normal.sample(x.len()));
+
+    // Noise to image
+    let mut y = x.fmap(|t| t.powi(2));
+    y = zip_with(|a, b| a + b, &y, &normal2.sample(y.len()));
+
+    // Initial parameter
+    let n_init = vec![1f64];
+    let data = hstack!(x.clone(), y.clone());
+
+    // Optimizer setting
+    let mut opt = Optimizer::new(data, quad);
+    let p = opt.set_init_param(n_init)
+        .set_max_iter(50)
+        .set_method(LevenbergMarquardt)
+        .optimize();
+    p.print();                  // Optimized parameter
+    opt.get_error().print();    // Optimized RMSE
+}
+
+fn quad(x: &Vec<f64>, n: Vec<AD>) -> Option<Vec<AD>> {
+    Some(
+        x.clone().into_iter()
+            .map(|t| AD1(t, 0f64))
+            .map(|t| t.pow(n[0]))
+            .collect()
+    )
+}
diff --git a/src/numerical/optimize.rs b/src/numerical/optimize.rs
index 3cc0431f..5b43c154 100644
--- a/src/numerical/optimize.rs
+++ b/src/numerical/optimize.rs
@@ -73,12 +73,10 @@
 //!     p.print();                  // Optimized parameter
 //!     opt.get_error().print();    // Optimized RMSE
 //!
-//!     // To prepare plotting
-//!     let z = quad(&x, p.to_ad_vec()).unwrap().to_f64_vec();
-//!
 //!     // Plot
 //!     //#[cfg(feature = "plot")]
 //!     //{
+//!     //    let z = quad(&x, p.to_ad_vec()).unwrap().to_f64_vec();
 //!     //    let mut plt = Plot2D::new();
 //!     //    plt.set_domain(x)
 //!     //        .insert_image(y)    // plot data
@@ -94,7 +92,7 @@
 //! fn quad(x: &Vec<f64>, n: Vec<AD>) -> Option<Vec<AD>> {
 //!     Some(
 //!         x.clone().into_iter()
-//!             .map(|t| AD::from(t))
+//!             .map(|t| AD1(t, 0f64))
 //!             .map(|t| t.pow(n[0]))
 //!             .collect()
 //!     )