Diameter

ω = Circle((0, 0), 1)
B = PointIn(Circle[(0, 0), 1])
A = PointIn(Circle[(0, 0), 1])
a = Line(A, B)
P2 = Intersect(Circle[(0, 0), 1], Line[A, B], 2)
P1 = Intersect(Circle[(0, 0), 1], Line[A, B], 1)
o = LineBisector(P1, P2)
O1 = Intersect(Circle[(0, 0), 1000], o, 1)
Diameter = Circle(O1, 1000)