def test_ellipse_geom(): x = Symbol('x', real=True) y = Symbol('y', real=True) t = Symbol('t', real=True) y1 = Symbol('y1', real=True) half = Rational(1, 2) p1 = Point(0, 0) p2 = Point(1, 1) p4 = Point(0, 1) e1 = Ellipse(p1, 1, 1) e2 = Ellipse(p2, half, 1) e3 = Ellipse(p1, y1, y1) c1 = Circle(p1, 1) c2 = Circle(p2, 1) c3 = Circle(Point(sqrt(2), sqrt(2)), 1) l1 = Line(p1, p2) # Test creation with three points cen, rad = Point(3 * half, 2), 5 * half assert Circle(Point(0, 0), Point(3, 0), Point(0, 4)) == Circle(cen, rad) assert Circle(Point(0, 0), Point(1, 1), Point(2, 2)) == Segment2D(Point2D(0, 0), Point2D(2, 2)) raises(ValueError, lambda: Ellipse(None, None, None, 1)) raises(GeometryError, lambda: Circle(Point(0, 0))) # Basic Stuff assert Ellipse(None, 1, 1).center == Point(0, 0) assert e1 == c1 assert e1 != e2 assert e1 != l1 assert p4 in e1 assert p2 not in e2 assert e1.area == pi assert e2.area == pi / 2 assert e3.area == pi * y1 * abs(y1) assert c1.area == e1.area assert c1.circumference == e1.circumference assert e3.circumference == 2 * pi * y1 assert e1.plot_interval() == e2.plot_interval() == [t, -pi, pi] assert e1.plot_interval(x) == e2.plot_interval(x) == [x, -pi, pi] assert c1.minor == 1 assert c1.major == 1 assert c1.hradius == 1 assert c1.vradius == 1 assert Ellipse((1, 1), 0, 0) == Point(1, 1) assert Ellipse((1, 1), 1, 0) == Segment(Point(0, 1), Point(2, 1)) assert Ellipse((1, 1), 0, 1) == Segment(Point(1, 0), Point(1, 2)) # Private Functions assert hash(c1) == hash(Circle(Point(1, 0), Point(0, 1), Point(0, -1))) assert c1 in e1 assert (Line(p1, p2) in e1) is False assert e1.__cmp__(e1) == 0 assert e1.__cmp__(Point(0, 0)) > 0 # Encloses assert e1.encloses(Segment(Point(-0.5, -0.5), Point(0.5, 0.5))) is True assert e1.encloses(Line(p1, p2)) is False assert e1.encloses(Ray(p1, p2)) is False assert e1.encloses(e1) is False assert e1.encloses( Polygon(Point(-0.5, -0.5), Point(-0.5, 0.5), Point(0.5, 0.5))) is True assert e1.encloses(RegularPolygon(p1, 0.5, 3)) is True assert e1.encloses(RegularPolygon(p1, 5, 3)) is False assert e1.encloses(RegularPolygon(p2, 5, 3)) is False assert e2.arbitrary_point() in e2 # Foci f1, f2 = Point(sqrt(12), 0), Point(-sqrt(12), 0) ef = Ellipse(Point(0, 0), 4, 2) assert ef.foci in [(f1, f2), (f2, f1)] # Tangents v = sqrt(2) / 2 p1_1 = Point(v, v) p1_2 = p2 + Point(half, 0) p1_3 = p2 + Point(0, 1) assert e1.tangent_lines(p4) == c1.tangent_lines(p4) assert e2.tangent_lines(p1_2) == [ Line(Point(3 / 2, 1), Point(3 / 2, 1 / 2)) ] assert e2.tangent_lines(p1_3) == [Line(Point(1, 2), Point(5 / 4, 2))] assert c1.tangent_lines(p1_1) != [Line(p1_1, Point(0, sqrt(2)))] assert c1.tangent_lines(p1) == [] assert e2.is_tangent(Line(p1_2, p2 + Point(half, 1))) assert e2.is_tangent(Line(p1_3, p2 + Point(half, 1))) assert c1.is_tangent(Line(p1_1, Point(0, sqrt(2)))) assert e1.is_tangent(Line(Point(0, 0), Point(1, 1))) is False assert c1.is_tangent(e1) is True assert c1.is_tangent(Ellipse(Point(2, 0), 1, 1)) is True assert c1.is_tangent(Polygon(Point(1, 1), Point(1, -1), Point(2, 0))) is True assert c1.is_tangent(Polygon(Point(1, 1), Point(1, 0), Point(2, 0))) is False assert Circle(Point(5, 5), 3).is_tangent(Circle(Point(0, 5), 1)) is False assert Ellipse(Point(5, 5), 2, 1).tangent_lines(Point(0, 0)) == \ [Line(Point(0, 0), Point(77/25, 132/25)), Line(Point(0, 0), Point(33/5, 22/5))] assert Ellipse(Point(5, 5), 2, 1).tangent_lines(Point(3, 4)) == \ [Line(Point(3, 4), Point(4, 4)), Line(Point(3, 4), Point(3, 5))] assert Circle(Point(5, 5), 2).tangent_lines(Point(3, 3)) == \ [Line(Point(3, 3), Point(4, 3)), Line(Point(3, 3), Point(3, 4))] assert Circle(Point(5, 5), 2).tangent_lines(Point(5 - 2*sqrt(2), 5)) == \ [Line(Point(5 - 2*sqrt(2), 5), Point(5 - sqrt(2), 5 - sqrt(2))), Line(Point(5 - 2*sqrt(2), 5), Point(5 - sqrt(2), 5 + sqrt(2))), ] # for numerical calculations, we shouldn't demand exact equality, # so only test up to the desired precision def lines_close(l1, l2, prec): """ tests whether l1 and 12 are within 10**(-prec) of each other """ return abs(l1.p1 - l2.p1) < 10**(-prec) and abs(l1.p2 - l2.p2) < 10**(-prec) def line_list_close(ll1, ll2, prec): return all(lines_close(l1, l2, prec) for l1, l2 in zip(ll1, ll2)) e = Ellipse(Point(0, 0), 2, 1) assert e.normal_lines(Point(0, 0)) == \ [Line(Point(0, 0), Point(0, 1)), Line(Point(0, 0), Point(1, 0))] assert e.normal_lines(Point(1, 0)) == \ [Line(Point(0, 0), Point(1, 0))] assert e.normal_lines((0, 1)) == \ [Line(Point(0, 0), Point(0, 1))] assert line_list_close(e.normal_lines(Point(1, 1), 2), [ Line(Point(-51 / 26, -1 / 5), Point(-25 / 26, 17 / 83)), Line(Point(28 / 29, -7 / 8), Point(57 / 29, -9 / 2)) ], 2) # test the failure of Poly.intervals and checks a point on the boundary p = Point(sqrt(3), S.Half) assert p in e assert line_list_close(e.normal_lines(p, 2), [ Line(Point(-341 / 171, -1 / 13), Point(-170 / 171, 5 / 64)), Line(Point(26 / 15, -1 / 2), Point(41 / 15, -43 / 26)) ], 2) # be sure to use the slope that isn't undefined on boundary e = Ellipse((0, 0), 2, 2 * sqrt(3) / 3) assert line_list_close(e.normal_lines((1, 1), 2), [ Line(Point(-64 / 33, -20 / 71), Point(-31 / 33, 2 / 13)), Line(Point(1, -1), Point(2, -4)) ], 2) # general ellipse fails except under certain conditions e = Ellipse((0, 0), x, 1) assert e.normal_lines((x + 1, 0)) == [Line(Point(0, 0), Point(1, 0))] raises(NotImplementedError, lambda: e.normal_lines((x + 1, 1))) # Properties major = 3 minor = 1 e4 = Ellipse(p2, minor, major) assert e4.focus_distance == sqrt(major**2 - minor**2) ecc = e4.focus_distance / major assert e4.eccentricity == ecc assert e4.periapsis == major * (1 - ecc) assert e4.apoapsis == major * (1 + ecc) assert e4.semilatus_rectum == major * (1 - ecc**2) # independent of orientation e4 = Ellipse(p2, major, minor) assert e4.focus_distance == sqrt(major**2 - minor**2) ecc = e4.focus_distance / major assert e4.eccentricity == ecc assert e4.periapsis == major * (1 - ecc) assert e4.apoapsis == major * (1 + ecc) # Intersection l1 = Line(Point(1, -5), Point(1, 5)) l2 = Line(Point(-5, -1), Point(5, -1)) l3 = Line(Point(-1, -1), Point(1, 1)) l4 = Line(Point(-10, 0), Point(0, 10)) pts_c1_l3 = [ Point(sqrt(2) / 2, sqrt(2) / 2), Point(-sqrt(2) / 2, -sqrt(2) / 2) ] assert intersection(e2, l4) == [] assert intersection(c1, Point(1, 0)) == [Point(1, 0)] assert intersection(c1, l1) == [Point(1, 0)] assert intersection(c1, l2) == [Point(0, -1)] assert intersection(c1, l3) in [pts_c1_l3, [pts_c1_l3[1], pts_c1_l3[0]]] assert intersection(c1, c2) == [Point(0, 1), Point(1, 0)] assert intersection(c1, c3) == [Point(sqrt(2) / 2, sqrt(2) / 2)] assert e1.intersection(l1) == [Point(1, 0)] assert e2.intersection(l4) == [] assert e1.intersection(Circle(Point(0, 2), 1)) == [Point(0, 1)] assert e1.intersection(Circle(Point(5, 0), 1)) == [] assert e1.intersection(Ellipse(Point(2, 0), 1, 1)) == [Point(1, 0)] assert e1.intersection(Ellipse(Point(5, 0), 1, 1)) == [] assert e1.intersection(Point(2, 0)) == [] assert e1.intersection(e1) == e1 assert intersection(Ellipse(Point(0, 0), 2, 1), Ellipse(Point(3, 0), 1, 2)) == [Point(2, 0)] assert intersection(Circle(Point(0, 0), 2), Circle(Point(3, 0), 1)) == [Point(2, 0)] assert intersection(Circle(Point(0, 0), 2), Circle(Point(7, 0), 1)) == [] assert intersection(Ellipse(Point(0, 0), 5, 17), Ellipse(Point(4, 0), 1, 0.2)) == [Point(5, 0)] assert intersection(Ellipse(Point(0, 0), 5, 17), Ellipse(Point(4, 0), 0.999, 0.2)) == [] assert Circle((0, 0), 1 / 2).intersection(Triangle( (-1, 0), (1, 0), (0, 1))) == [Point(-1 / 2, 0), Point(1 / 2, 0)] raises(TypeError, lambda: intersection(e2, Line((0, 0, 0), (0, 0, 1)))) raises(TypeError, lambda: intersection(e2, Rational(12))) # some special case intersections csmall = Circle(p1, 3) cbig = Circle(p1, 5) cout = Circle(Point(5, 5), 1) # one circle inside of another assert csmall.intersection(cbig) == [] # separate circles assert csmall.intersection(cout) == [] # coincident circles assert csmall.intersection(csmall) == csmall v = sqrt(2) t1 = Triangle(Point(0, v), Point(0, -v), Point(v, 0)) points = intersection(t1, c1) assert len(points) == 4 assert Point(0, 1) in points assert Point(0, -1) in points assert Point(v / 2, v / 2) in points assert Point(v / 2, -v / 2) in points circ = Circle(Point(0, 0), 5) elip = Ellipse(Point(0, 0), 5, 20) assert intersection(circ, elip) in \ [[Point(5, 0), Point(-5, 0)], [Point(-5, 0), Point(5, 0)]] assert elip.tangent_lines(Point(0, 0)) == [] elip = Ellipse(Point(0, 0), 3, 2) assert elip.tangent_lines(Point(3, 0)) == \ [Line(Point(3, 0), Point(3, -12))] e1 = Ellipse(Point(0, 0), 5, 10) e2 = Ellipse(Point(2, 1), 4, 8) a = 53 / 17 c = 2 * sqrt(3991) / 17 ans = [Point(a - c / 8, a / 2 + c), Point(a + c / 8, a / 2 - c)] assert e1.intersection(e2) == ans e2 = Ellipse(Point(x, y), 4, 8) c = sqrt(3991) ans = [ Point(-c / 68 + a, 2 * c / 17 + a / 2), Point(c / 68 + a, -2 * c / 17 + a / 2) ] assert [p.subs({x: 2, y: 1}) for p in e1.intersection(e2)] == ans # Combinations of above assert e3.is_tangent(e3.tangent_lines(p1 + Point(y1, 0))[0]) e = Ellipse((1, 2), 3, 2) assert e.tangent_lines(Point(10, 0)) == \ [Line(Point(10, 0), Point(1, 0)), Line(Point(10, 0), Point(14/5, 18/5))] # encloses_point e = Ellipse((0, 0), 1, 2) assert e.encloses_point(e.center) assert e.encloses_point(e.center + Point(0, e.vradius - Rational(1, 10))) assert e.encloses_point(e.center + Point(e.hradius - Rational(1, 10), 0)) assert e.encloses_point(e.center + Point(e.hradius, 0)) is False assert e.encloses_point(e.center + Point(e.hradius + Rational(1, 10), 0)) is False e = Ellipse((0, 0), 2, 1) assert e.encloses_point(e.center) assert e.encloses_point(e.center + Point(0, e.vradius - Rational(1, 10))) assert e.encloses_point(e.center + Point(e.hradius - Rational(1, 10), 0)) assert e.encloses_point(e.center + Point(e.hradius, 0)) is False assert e.encloses_point(e.center + Point(e.hradius + Rational(1, 10), 0)) is False assert c1.encloses_point(Point(1, 0)) is False assert c1.encloses_point(Point(0.3, 0.4)) is True assert e.scale(2, 3) == Ellipse((0, 0), 4, 3) assert e.scale(3, 6) == Ellipse((0, 0), 6, 6) assert e.rotate(pi) == e assert e.rotate(pi, (1, 2)) == Ellipse(Point(2, 4), 2, 1) raises(NotImplementedError, lambda: e.rotate(pi / 3)) # Circle rotation tests (Issue #11743) # Link - https://github.com/sympy/sympy/issues/11743 cir = Circle(Point(1, 0), 1) assert cir.rotate(pi / 2) == Circle(Point(0, 1), 1) assert cir.rotate(pi / 3) == Circle(Point(1 / 2, sqrt(3) / 2), 1) assert cir.rotate(pi / 3, Point(1, 0)) == Circle(Point(1, 0), 1) assert cir.rotate(pi / 3, Point(0, 1)) == Circle( Point(1 / 2 + sqrt(3) / 2, 1 / 2 + sqrt(3) / 2), 1)
def convex_hull(*args): """The convex hull surrounding the Points contained in the list of entities. Parameters ========== args : a collection of Points, Segments and/or Polygons Returns ======= convex_hull : Polygon Notes ===== This can only be performed on a set of non-symbolic points. References ========== [1] http://en.wikipedia.org/wiki/Graham_scan [2] Andrew's Monotone Chain Algorithm (A.M. Andrew, "Another Efficient Algorithm for Convex Hulls in Two Dimensions", 1979) http://geomalgorithms.com/a10-_hull-1.html See Also ======== sympy.geometry.point.Point, sympy.geometry.polygon.Polygon Examples ======== >>> from sympy.geometry import Point, convex_hull >>> points = [(1,1), (1,2), (3,1), (-5,2), (15,4)] >>> convex_hull(*points) Polygon(Point(-5, 2), Point(1, 1), Point(3, 1), Point(15, 4)) """ from .entity import GeometryEntity from .point import Point from .line import Segment from .polygon import Polygon p = set() for e in args: if not isinstance(e, GeometryEntity): try: e = Point(e) except NotImplementedError: raise ValueError( '%s is not a GeometryEntity and cannot be made into Point' % str(e)) if isinstance(e, Point): p.add(e) elif isinstance(e, Segment): p.update(e.points) elif isinstance(e, Polygon): p.update(e.vertices) else: raise NotImplementedError('Convex hull for %s not implemented.' % type(e)) p = list(p) if len(p) == 1: return p[0] elif len(p) == 2: return Segment(p[0], p[1]) def _orientation(p, q, r): '''Return positive if p-q-r are clockwise, neg if ccw, zero if collinear.''' return (q.y - p.y) * (r.x - p.x) - (q.x - p.x) * (r.y - p.y) # scan to find upper and lower convex hulls of a set of 2d points. U = [] L = [] p.sort(key=lambda x: x.args) for p_i in p: while len(U) > 1 and _orientation(U[-2], U[-1], p_i) <= 0: U.pop() while len(L) > 1 and _orientation(L[-2], L[-1], p_i) >= 0: L.pop() U.append(p_i) L.append(p_i) U.reverse() convexHull = tuple(L + U[1:-1]) if len(convexHull) == 2: return Segment(convexHull[0], convexHull[1]) return Polygon(*convexHull)
def test_is_tangent(): e1 = Ellipse(Point(0, 0), 3, 5) c1 = Circle(Point(2, -2), 7) assert e1.is_tangent(Point(0, 0)) is False assert e1.is_tangent(Point(3, 0)) is False assert e1.is_tangent(e1) is True assert e1.is_tangent(Ellipse((0, 0), 1, 2)) is False assert e1.is_tangent(Ellipse((0, 0), 3, 2)) is True assert c1.is_tangent(Ellipse((2, -2), 7, 1)) is True assert c1.is_tangent(Circle((11, -2), 2)) is True assert c1.is_tangent(Circle((7, -2), 2)) is True assert c1.is_tangent(Ray((-5, -2), (-15, -20))) is False assert c1.is_tangent(Ray((-3, -2), (-15, -20))) is False assert c1.is_tangent(Ray((-3, -22), (15, 20))) is False assert c1.is_tangent(Ray((9, 20), (9, -20))) is True assert e1.is_tangent(Segment((2, 2), (-7, 7))) is False assert e1.is_tangent(Segment((0, 0), (1, 2))) is False assert c1.is_tangent(Segment((0, 0), (-5, -2))) is False assert e1.is_tangent(Segment((3, 0), (12, 12))) is False assert e1.is_tangent(Segment((12, 12), (3, 0))) is False assert e1.is_tangent(Segment((-3, 0), (3, 0))) is False assert e1.is_tangent(Segment((-3, 5), (3, 5))) is True assert e1.is_tangent(Line((0, 0), (1, 1))) is False assert e1.is_tangent(Line((-3, 0), (-2.99, -0.001))) is False assert e1.is_tangent(Line((-3, 0), (-3, 1))) is True assert e1.is_tangent(Polygon((0, 0), (5, 5), (5, -5))) is False assert e1.is_tangent(Polygon((-100, -50), (-40, -334), (-70, -52))) is False assert e1.is_tangent(Polygon((-3, 0), (3, 0), (0, 1))) is False assert e1.is_tangent(Polygon((-3, 0), (3, 0), (0, 5))) is False assert e1.is_tangent(Polygon((-3, 0), (0, -5), (3, 0), (0, 5))) is False assert e1.is_tangent(Polygon((-3, -5), (-3, 5), (3, 5), (3, -5))) is True assert c1.is_tangent(Polygon((-3, -5), (-3, 5), (3, 5), (3, -5))) is False assert e1.is_tangent(Polygon((0, 0), (3, 0), (7, 7), (0, 5))) is False assert e1.is_tangent(Polygon((3, 12), (3, -12), (6, 5))) is True assert e1.is_tangent(Polygon((3, 12), (3, -12), (0, -5), (0, 5))) is False assert e1.is_tangent(Polygon((3, 0), (5, 7), (6, -5))) is False raises(TypeError, lambda: e1.is_tangent(Point(0, 0, 0))) raises(TypeError, lambda: e1.is_tangent(Rational(5)))
def convex_hull(*args, **kwargs): """The convex hull surrounding the Points contained in the list of entities. Parameters ========== args : a collection of Points, Segments and/or Polygons Returns ======= convex_hull : Polygon if ``polygon`` is True else as a tuple `(U, L)` where ``L`` and ``U`` are the lower and upper hulls, respectively. Notes ===== This can only be performed on a set of points whose coordinates can be ordered on the number line. References ========== [1] https://en.wikipedia.org/wiki/Graham_scan [2] Andrew's Monotone Chain Algorithm (A.M. Andrew, "Another Efficient Algorithm for Convex Hulls in Two Dimensions", 1979) http://geomalgorithms.com/a10-_hull-1.html See Also ======== sympy.geometry.point.Point, sympy.geometry.polygon.Polygon Examples ======== >>> from sympy.geometry import Point, convex_hull >>> points = [(1, 1), (1, 2), (3, 1), (-5, 2), (15, 4)] >>> convex_hull(*points) Polygon(Point2D(-5, 2), Point2D(1, 1), Point2D(3, 1), Point2D(15, 4)) >>> convex_hull(*points, **dict(polygon=False)) ([Point2D(-5, 2), Point2D(15, 4)], [Point2D(-5, 2), Point2D(1, 1), Point2D(3, 1), Point2D(15, 4)]) """ from .entity import GeometryEntity from .point import Point from .line import Segment from .polygon import Polygon polygon = kwargs.get('polygon', True) p = OrderedSet() for e in args: if not isinstance(e, GeometryEntity): try: e = Point(e) except NotImplementedError: raise ValueError( '%s is not a GeometryEntity and cannot be made into Point' % str(e)) if isinstance(e, Point): p.add(e) elif isinstance(e, Segment): p.update(e.points) elif isinstance(e, Polygon): p.update(e.vertices) else: raise NotImplementedError('Convex hull for %s not implemented.' % type(e)) # make sure all our points are of the same dimension if any(len(x) != 2 for x in p): raise ValueError('Can only compute the convex hull in two dimensions') p = list(p) if len(p) == 1: return p[0] if polygon else (p[0], None) elif len(p) == 2: s = Segment(p[0], p[1]) return s if polygon else (s, None) def _orientation(p, q, r): '''Return positive if p-q-r are clockwise, neg if ccw, zero if collinear.''' return (q.y - p.y) * (r.x - p.x) - (q.x - p.x) * (r.y - p.y) # scan to find upper and lower convex hulls of a set of 2d points. U = [] L = [] try: p.sort(key=lambda x: x.args) except TypeError: raise ValueError("The points could not be sorted.") for p_i in p: while len(U) > 1 and _orientation(U[-2], U[-1], p_i) <= 0: U.pop() while len(L) > 1 and _orientation(L[-2], L[-1], p_i) >= 0: L.pop() U.append(p_i) L.append(p_i) U.reverse() convexHull = tuple(L + U[1:-1]) if len(convexHull) == 2: s = Segment(convexHull[0], convexHull[1]) return s if polygon else (s, None) if polygon: return Polygon(*convexHull) else: U.reverse() return (U, L)