hmmmm
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4f7c4a5699
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69037ec771
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@ -2,7 +2,7 @@
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import random
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from collections import namedtuple
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import matplotlib.pyplot as plt
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from math import atan2, degrees, tau, pi, acos, sqrt
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from math import acos, sqrt
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Point = namedtuple('Point', 'x y')
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Vector = namedtuple('Vector', 'x y')
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@ -18,8 +18,19 @@ def gen_point():
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return p_i
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def calc_angle(v: Vector, upside_down=False) -> float:
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return (90 - degrees(atan2(v.y, v.x)) - 180*upside_down) % 360
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def calc_angle(v1: Vector, v2: Vector) -> float:
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dot = (v1.x * v2.x) + (v1.y * v2.y)
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len_1 = sqrt(v1.x**2 + v1.y**2)
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len_2 = sqrt(v2.x**2 + v2.y**2)
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tmp = dot / (len_1 * len_2)
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# pls
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hmmmmmmm = round(tmp, 6)
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return acos(hmmmmmmm)
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def calc_vector(p1: Point, p2: Point) -> Vector:
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@ -41,16 +52,15 @@ def display(points, hull):
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def rapper(points: set):
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min_pt = min(points)
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max_pt = max(points)
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hull = [min_pt]
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upside_down = False
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comp_vec = Vector(0, 1)
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while True:
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hull.append(min(points - {hull[-1]},
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key=lambda p: calc_angle(calc_vector(hull[-1], p), upside_down)))
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if hull[-1].x == max_pt.x:
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upside_down = True
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key=lambda p: calc_angle(comp_vec, calc_vector(hull[-1], p))))
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comp_vec = calc_vector(hull[-2], hull[-1])
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display(points, hull)
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if hull[-1] == min_pt:
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break
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106
h2/quick_hull.py
Normal file
106
h2/quick_hull.py
Normal file
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@ -0,0 +1,106 @@
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import random
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from collections import namedtuple
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import matplotlib.pyplot as plt
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from enum import Enum, auto
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from math import atan2, degrees, tau, pi, acos, sqrt
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Point = namedtuple('Point', 'x y')
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class Side(Enum):
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ON = auto()
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ABOVE = auto()
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BELOW = auto()
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def display(points, hull):
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x = [point.x for point in points]
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y = [point.y for point in points]
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h_x = [point.x for point in hull]
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h_y = [point.y for point in hull]
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plt.plot(h_x, h_y, 'ro-')
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plt.scatter(x, y)
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plt.show()
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def gen_point():
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a = random.uniform(1, 5)
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b = random.uniform(1, 5)
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x_i = random.uniform(1, 5)
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p_i = Point(x_i, a * x_i + b)
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return p_i
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def sidedness(p1, p2, p3, eps=0.0000001):
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y = p1.y * (p3.x - p2.x)
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x = p1.x
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a = (p3.y - p2.y)
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b = p3.y * (p3.x - p2.x) - a * p3.x
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line = a*x+b
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if y - eps < line < y + eps:
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return [Side.ON, y - line]
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elif y > line:
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return [Side.ABOVE, y - line]
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return [Side.BELOW, y - line]
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def prune_below_find_highest(points: set, line_segment, side = Side.BELOW, lel=max):
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min_pt, max_pt = line_segment
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above_pts = []
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for point in points:
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sidedness_res = sidedness(min_pt, max_pt, point)
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if sidedness_res[0] != side:
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above_pts.append(point)
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highest_above = lel(above_pts, key=lambda pt: pt[1])
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return above_pts, highest_above
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def find_line_segment(points):
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min_pt = min(points, key=lambda pt: pt.x)
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max_pt = max(points, key=lambda pt: pt.x)
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return min_pt, max_pt
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def quick_hull(points, side=Side.BELOW, lel=max, hull=None):
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if hull is None:
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hull = set()
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print(len(points))
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if len(points) <= 2:
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return hull
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min_pt, max_pt = find_line_segment(points)
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above_points, max_dist_pt = prune_below_find_highest(points, (min_pt, max_pt), side, lel)
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left_side = prune_below_find_highest(points, (min_pt, max_dist_pt), side, lel)[0]
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right_side = prune_below_find_highest(points, (max_dist_pt, max_pt), side, lel)[0]
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hull.add(max_dist_pt)
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quick_hull(left_side, side, lel, hull=hull).union(quick_hull(right_side, side, lel, hull=hull))
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return hull
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points = {Point(2, 5), Point(3, 1), Point(3, 4), Point(9, 4), Point(1, 5), Point(5, 7)}
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#points = {gen_point() for _ in range(10)}
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line_segment = find_line_segment(points)
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uh_hull = quick_hull(points)
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lh_hull = quick_hull(points, Side.ABOVE, min)
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hull = uh_hull.union(lh_hull)
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display(points, hull)
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