import sympy import joblib import tqdm def gcd(a, b): if b == 0: return a return gcd(b, a % b) class Point: def __init__(self, x, y): self.x = x self.y = y def __str__(self): return f"({self.x}, {self.y})" def magnitude(self): return self.x * self.x + self.y * self.y def distance_to(self, other): dx = other.x - self.x dy = other.y - self.y return sympy.sqrt(dx * dx + dy * dy) def circumcenter(A: Point, B: Point, C: Point) -> Point: D = sympy.S(2) * (A.x * (B.y - C.y) + B.x * (C.y - A.y) + C.x * (A.y - B.y)) Ux = (A.magnitude() * (B.y - C.y) + B.magnitude() * (C.y - A.y) + C.magnitude() * (A.y - B.y)) / D Uy = (A.magnitude() * (C.x - B.x) + B.magnitude() * (A.x - C.x) + C.magnitude() * (B.x - A.x)) / D return Point(Ux, Uy) def lerp(src: Point, dst: Point, dist: float) -> Point: total = src.distance_to(dst) ratio = sympy.Rational(dist, total) dx = src.x + (dst.x - src.x) * ratio dy = src.y + (dst.y - src.y) * ratio return Point(dx, dy) def heron(a, b, c): a, b, c = sympy.S(a), sympy.S(b), sympy.S(c) p = (a + b + c) / sympy.S(2) return sympy.sqrt(p * (p - a) * (p - b) * (p - c)) def inv_law_cosines(a, b, c): # given a, b, c return C return sympy.acos((a * a + b * b - c * c) / (sympy.S(2) * a * b)) def compute_d(A: Point, B: Point, C: Point, r1: float, r2: float, r3: float) -> float: r1, r2, r3 = sympy.S(r1), sympy.S(r2), sympy.S(r3) ABmid = lerp(A, B, r1) BCmid = lerp(B, C, r2) CAmid = lerp(C, A, r3) D = circumcenter(ABmid, BCmid, CAmid) re = sympy.symbols("re") t1 = heron(r1 + r3, r1 + re, r3 + re) t2 = heron(r1 + r2, r1 + re, r2 + re) t3 = heron(r2 + r3, r2 + re, r3 + re) tfull = heron(r1 + r2, r1 + r3, r2 + r3) eq = sympy.Eq(t1 + t2 + t3, tfull) result = sympy.solve(eq, re) result = result[0].evalf() # print(f"radius of E is {result}") EAB = inv_law_cosines(r1 + result, r1 + r2, r2 + result) Ex = (r1 + result) * sympy.cos(EAB) Ey = (r1 + result) * sympy.sin(EAB) E = Point(Ex, Ey) # print(D, E) return D.distance_to(E).evalf() total = 0 count = 0 def create_loop(): for r1 in range(1, 101 - 2): for r2 in range(r1 + 1, 101 - 1): for r3 in range(r2 + 1, 101): if gcd(gcd(r1, r2), r3) != 1: continue yield (r1, r2, r3) def calc(x): r1, r2, r3 = x # build a triangle out of the side lengths # A is at (0, 0), a = r2 + r3 # B is at (c, 0), b = r1 + r3 # c = r1 + r2 # C is at () a = sympy.S(r2 + r3) b = sympy.S(r1 + r3) c = sympy.S(r1 + r2) A = Point(sympy.S(0), sympy.S(0)) B = Point(c, sympy.S(0)) CAB = sympy.acos(sympy.Rational(b * b + c * c - a * a, 2.0 * b * c)) Cx = b * sympy.cos(CAB) Cy = b * sympy.sin(CAB) C = Point(Cx, Cy) d = compute_d(A, B, C, r1, r2, r3) return d print(f"d({r1}, {r2}, {r3}) = {d}") total = len(list(create_loop())) L = joblib.Parallel(n_jobs=8)(joblib.delayed(calc)(tup) for tup in tqdm.tqdm(create_loop(), total=total)) print(sum(L) / len(L))