diff --git a/__tests__/CDFunctor__Test.re b/__tests__/CDFunctor__Test.re
index 031b55fc..69e483e3 100644
--- a/__tests__/CDFunctor__Test.re
+++ b/__tests__/CDFunctor__Test.re
@@ -46,4 +46,20 @@ describe("CDF", () => {
     };
     expect(a) |> toEqual(b);
   });
+  test("minX", () => {
+    module CDF =
+      CDFunctor.Make({
+        let shape: DistributionTypes.xyShape =
+          CDFunctor.order({xs: [|20., 4., 8.|], ys: [|8., 9., 2.|]});
+      });
+    expect(CDF.minX()) |> toEqual(4.);
+  });
+  test("maxX", () => {
+    module CDF =
+      CDFunctor.Make({
+        let shape: DistributionTypes.xyShape =
+          CDFunctor.order({xs: [|20., 4., 8.|], ys: [|8., 9., 2.|]});
+      });
+    expect(CDF.maxX()) |> toEqual(20.);
+  });
 });
diff --git a/src/utility/lib/CDFunctor.re b/src/utility/lib/CDFunctor.re
index 09848aaf..3db4f574 100644
--- a/src/utility/lib/CDFunctor.re
+++ b/src/utility/lib/CDFunctor.re
@@ -5,7 +5,7 @@ exception ShapeWrong(string);
 let order = (shape: DistributionTypes.xyShape): DistributionTypes.xyShape => {
   let xy =
     shape.xs
-    |> Array.mapi((i, x) => [x, shape.ys[i]])
+    |> Array.mapi((i, x) => [x, shape.ys |> Array.get(_, i)])
     |> Belt.SortArray.stableSortBy(_, ([a, _], [b, _]) => a > b ? 1 : (-1));
   {
     xs: xy |> Array.map(([x, _]) => x),
@@ -26,6 +26,8 @@ module Make = (Config: Config) => {
   if (!Belt.SortArray.isSorted(Config.shape.xs, (a, b) => a > b ? 1 : (-1))) {
     raise(ShapeWrong("Arrays of \"xs\" and \"ys\" have different sizes."));
   };
-
+  let minX = () => Config.shape.xs |> Array.get(_, 0);
+  let maxX = () =>
+    Config.shape.xs |> Array.get(_, Array.length(Config.shape.xs) - 1);
   1;
 };
diff --git a/src/utility/lib/continuousDistribution.js b/src/utility/lib/continuousDistribution.js
index 65f6e85d..a1eb3117 100644
--- a/src/utility/lib/continuousDistribution.js
+++ b/src/utility/lib/continuousDistribution.js
@@ -42,6 +42,7 @@ class ContinuousDistribution {
   }
 
   /**
+   * @Done
    * @param {number[]} xs
    * @param {number[]} ys
    * @return {boolean}
@@ -51,6 +52,7 @@ class ContinuousDistribution {
   }
 
   /**
+   * @Done
    * @param xs
    * @returns {boolean}
    */
@@ -59,6 +61,7 @@ class ContinuousDistribution {
   }
 
   /**
+   * @Done
    * @returns {number}
    */
   minX() {
@@ -66,6 +69,7 @@ class ContinuousDistribution {
   }
 
   /**
+   * @Done
    * @returns {number}
    */
   maxX() {