From 7ad637fe35a14083e95f3305d762790932427b39 Mon Sep 17 00:00:00 2001
From: Alexander Munch-Hansen <alexmunchhansen@gmail.com>
Date: Mon, 17 Sep 2018 17:06:20 +0200
Subject: [PATCH] Added gift_wrapper stuff

---
 h2/gift_wrapper.py | 64 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)
 create mode 100644 h2/gift_wrapper.py

diff --git a/h2/gift_wrapper.py b/h2/gift_wrapper.py
new file mode 100644
index 0000000..8064674
--- /dev/null
+++ b/h2/gift_wrapper.py
@@ -0,0 +1,64 @@
+# Use atan2 instead of acos to calc angle; atan2(x,y) of the point we potentially want to add
+import random
+from collections import namedtuple
+import matplotlib.pyplot as plt
+from math import atan2, degrees, tau, pi
+
+Point = namedtuple('Point', 'x y')
+Vector = namedtuple('Vector', 'x y')
+
+
+def gen_point():
+    a = random.uniform(1, 5)
+    b = random.uniform(1, 5)
+
+    x_i = random.uniform(1, 5)
+    p_i = Point(x_i, a * x_i + b)
+
+    return p_i
+
+
+def calc_angle(v1: Vector) -> float:
+    # x = atan2(v1.y, v1.x)
+
+
+    theta_deg = atan2(-v1.y, -v1.x) / pi * 180 + 180
+
+    lel = (90 - theta_deg) % 360
+    # degrees = (atan2(-v1.y, -v1.x)) + 180
+
+    return lel
+
+
+def calc_vector(p1: Point, p2: Point) -> Vector:
+    return Vector((p2.x - p1.x), (p2.y - p1.y))
+
+def display(points, hull):
+    x = [point.x for point in points]
+    y = [point.y for point in points]
+
+    h_x = [point.x for point in hull]
+    h_y = [point.y for point in hull]
+
+    plt.plot(h_x, h_y, 'ro-')
+
+    plt.scatter(x, y)
+    plt.show()
+
+
+def rapper(points: set):
+    min_pt = min(points)
+    hull = [min_pt]
+
+    while True:
+        hull.append(min(points - {hull[-1]},
+                        key=lambda p: calc_angle(calc_vector(hull[-1], p))))
+        display(points, hull)
+        if hull[-1] == min_pt:
+            break
+
+    return hull
+
+
+points = {gen_point() for _ in range(10)}
+hull = rapper(points)