diff --git a/__tests__/Functions__Test.re b/__tests__/Functions__Test.re
index a0500e00..d5cc0d03 100644
--- a/__tests__/Functions__Test.re
+++ b/__tests__/Functions__Test.re
@@ -60,4 +60,13 @@ describe("Functions", () => {
     expect(Functions.min([|(-1.), (-2.), 0., 20., (-2.2)|]))
     |> toEqual(-2.2)
   });
+  test("max#1", () => {
+    expect(Functions.max([|1., 2., 3.|])) |> toEqual(3.)
+  });
+  test("max#2", () => {
+    expect(Functions.max([|(-1.), (-2.), 0., 20.|])) |> toEqual(20.)
+  });
+  test("max#3", () => {
+    expect(Functions.max([|(-1.), (-2.), 0., (-2.2)|])) |> toEqual(0.)
+  });
 });
diff --git a/src/utility/lib/Functions.re b/src/utility/lib/Functions.re
index 0f310966..4600f237 100644
--- a/src/utility/lib/Functions.re
+++ b/src/utility/lib/Functions.re
@@ -12,7 +12,7 @@ let interpolate =
 let sum = Belt.Array.reduce(_, 0., (i, j) => i +. j);
 let mean = a => sum(a) /. (Array.length(a) |> float_of_int);
 let min = a => Belt.Array.reduce(a, a[0], (i, j) => i < j ? i : j);
-let max = Belt.Array.reduce(_, 0., (i, j) => i > j ? i : j);
+let max = a => Belt.Array.reduce(a, a[0], (i, j) => i > j ? i : j);
 let up = (a, b) => Array.make(b - a, a) |> Array.mapi((i, c) => c + i);
 let down = (a, b) => Array.make(a - b, a) |> Array.mapi((i, c) => c - i);
 let range = (min: float, max: float, n: int): array(float) => {