def test_point_sort():
assert point_sort([Point(0, 0), Point(1, 0), Point(1, 1)]) == \
[Point2D(1, 1), Point2D(1, 0), Point2D(0, 0)]
fig6 = Polygon((0, 0), (1, 0), (1, 1))
assert polytope_integrate(fig6, x * y) == Rational(-1, 8)
assert polytope_integrate(fig6, x * y, clockwise=True) == Rational(1, 8)
def intersection(self, o):
"""The intersection of the parabola and another geometrical entity `o`.
Parameters
==========
o : GeometryEntity, LinearEntity
Returns
=======
intersection : list of GeometryEntity objects
Examples
========
>>> from sympy import Parabola, Point, Ellipse, Line, Segment
>>> p1 = Point(0,0)
>>> l1 = Line(Point(1, -2), Point(-1,-2))
>>> parabola1 = Parabola(p1, l1)
>>> parabola1.intersection(Ellipse(Point(0, 0), 2, 5))
[Point2D(-2, 0), Point2D(2, 0)]
>>> parabola1.intersection(Line(Point(-7, 3), Point(12, 3)))
[Point2D(-4, 3), Point2D(4, 3)]
>>> parabola1.intersection(Segment((-12, -65), (14, -68)))
[]
"""
x, y = symbols("x y", real=True)
parabola_eq = self.equation()
if isinstance(o, Parabola):
if o in self:
return [o]
else:
return list(
ordered(
[Point(i) for i in solve([parabola_eq, o.equation()], [x, y])]
)
)
elif isinstance(o, Point2D):
if simplify(parabola_eq.subs(([(x, o._args[0]), (y, o._args[1])]))) == 0:
return [o]
else:
return []
elif isinstance(o, (Segment2D, Ray2D)):
result = solve(
[parabola_eq, Line2D(o.points[0], o.points[1]).equation()], [x, y]
)
return list(ordered([Point2D(i) for i in result if i in o]))
elif isinstance(o, (Line2D, Ellipse)):
return list(
ordered(
[Point2D(i) for i in solve([parabola_eq, o.equation()], [x, y])]
)
)
elif isinstance(o, LinearEntity3D):
raise TypeError("Entity must be two dimensional, not three dimensional")
else:
raise TypeError("Wrong type of argument were put")
def test_issue_13230():
c1 = Circle(Point2D(3, sqrt(5)), 5)
c2 = Circle(Point2D(4, sqrt(7)), 6)
assert intersection(c1, c2) == [
Point2D(
-1 + (-sqrt(7) + sqrt(5)) * (-2 * sqrt(7) / 29 + 9 * sqrt(5) / 29 +
sqrt(196 * sqrt(35) + 1941) / 29),
-2 * sqrt(7) / 29 + 9 * sqrt(5) / 29 +
sqrt(196 * sqrt(35) + 1941) / 29),
Point2D(
-1 + (-sqrt(7) + sqrt(5)) * (-sqrt(196 * sqrt(35) + 1941) / 29 -
2 * sqrt(7) / 29 + 9 * sqrt(5) / 29),
-sqrt(196 * sqrt(35) + 1941) / 29 - 2 * sqrt(7) / 29 +
9 * sqrt(5) / 29)
]
def test_object_from_equation():
from sympy.abc import x, y, a, b
assert Circle(x**2 + y**2 + 3*x + 4*y - 8) == Circle(Point2D(S(-3) / 2, -2),
sqrt(57) / 2)
assert Circle(x**2 + y**2 + 6*x + 8*y + 25) == Circle(Point2D(-3, -4), 0)
assert Circle(a**2 + b**2 + 6*a + 8*b + 25, x='a', y='b') == Circle(Point2D(-3, -4), 0)
assert Circle(x**2 + y**2 - 25) == Circle(Point2D(0, 0), 5)
assert Circle(x**2 + y**2) == Circle(Point2D(0, 0), 0)
assert Circle(a**2 + b**2, x='a', y='b') == Circle(Point2D(0, 0), 0)
assert Circle(x**2 + y**2 + 6*x + 8) == Circle(Point2D(-3, 0), 1)
assert Circle(x**2 + y**2 + 6*y + 8) == Circle(Point2D(0, -3), 1)
assert Circle(6*(x**2) + 6*(y**2) + 6*x + 8*y - 25) == Circle(Point2D(Rational(-1, 2), Rational(-2, 3)), 5*sqrt(37)/6)
assert Circle(Eq(a**2 + b**2, 25), x='a', y=b) == Circle(Point2D(0, 0), 5)
raises(GeometryError, lambda: Circle(x**2 + y**2 + 3*x + 4*y + 26))
raises(GeometryError, lambda: Circle(x**2 + y**2 + 25))
raises(GeometryError, lambda: Circle(a**2 + b**2 + 25, x='a', y='b'))
raises(GeometryError, lambda: Circle(x**2 + 6*y + 8))
raises(GeometryError, lambda: Circle(6*(x ** 2) + 4*(y**2) + 6*x + 8*y + 25))
raises(ValueError, lambda: Circle(a**2 + b**2 + 3*a + 4*b - 8))
def test_reflect():
b = Symbol('b')
m = Symbol('m')
l = Line((0, b), slope=m)
t1 = Triangle((0, 0), (1, 0), (2, 3))
assert t1.area == -t1.reflect(l).area
e = Ellipse((1, 0), 1, 2)
assert e.area == -e.reflect(Line((1, 0), slope=0)).area
assert e.area == -e.reflect(Line((1, 0), slope=oo)).area
raises(NotImplementedError, lambda: e.reflect(Line((1, 0), slope=m)))
assert Circle((0, 1), 1).reflect(Line((0, 0), (1, 1))) == Circle(Point2D(1, 0), -1)
def get_insert_pos(chain: Chain, line: Line, point: Point) -> int:
lp = chain.index(line[0]) if chain.count(line[0]) == 1 else None
rp = chain.index(line[1]) if chain.count(line[1]) == 1 else None
if not lp:
lp = 0 if rp < len(chain) - 1 - rp else len(chain) - 1
if not rp:
rp = 0 if lp < len(chain) - 1 - lp else len(chain) - 1
if fabs(lp - rp) == 1:
return max(lp, rp)
if lp < rp:
for i in range(lp + 1, rp):
if Point2D(chain[lp]).distance(point) < \
Point2D(point).distance(chain[i]):
return i
for i in range(lp - 1, rp, -1):
if Point2D(chain[lp]).distance(point) < \
Point2D(point).distance(chain[i]):
return i + 1
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 = S.Half
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(ValueError, lambda: Ellipse())
raises(GeometryError, lambda: Circle(Point(0, 0)))
raises(GeometryError, lambda: Circle(Symbol('x')*Symbol('y')))
# 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 e1 in e1
assert e2 in e2
assert 1 not in e2
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
raises(ValueError, lambda: Ellipse(Point(x, y), 1, 1).arbitrary_point(parameter='x'))
# 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(Rational(3, 2), 1), Point(Rational(3, 2), S.Half))]
assert e2.tangent_lines(p1_3) == [Line(Point(1, 2), Point(Rational(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(Rational(77, 25), Rational(132, 25))),
Line(Point(0, 0), Point(Rational(33, 5), Rational(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))), ]
assert Circle(Point(5, 5), 5).tangent_lines(Point(4, 0)) == \
[Line(Point(4, 0), Point(Rational(40, 13), Rational(5, 13))),
Line(Point(4, 0), Point(5, 0))]
assert Circle(Point(5, 5), 5).tangent_lines(Point(0, 6)) == \
[Line(Point(0, 6), Point(0, 7)),
Line(Point(0, 6), Point(Rational(5, 13), Rational(90, 13)))]
# 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(Rational(-51, 26), Rational(-1, 5)), Point(Rational(-25, 26), Rational(17, 83))),
Line(Point(Rational(28, 29), Rational(-7, 8)), Point(Rational(57, 29), Rational(-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(Rational(-341, 171), Rational(-1, 13)), Point(Rational(-170, 171), Rational(5, 64))),
Line(Point(Rational(26, 15), Rational(-1, 2)), Point(Rational(41, 15), Rational(-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(Rational(-64, 33), Rational(-20, 71)), Point(Rational(-31, 33), Rational(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), S.Half).intersection(
Triangle((-1, 0), (1, 0), (0, 1))) == [
Point(Rational(-1, 2), 0), Point(S.Half, 0)]
raises(TypeError, lambda: intersection(e2, Line((0, 0, 0), (0, 0, 1))))
raises(TypeError, lambda: intersection(e2, Rational(12)))
raises(TypeError, lambda: Ellipse.intersection(e2, 1))
# 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 = Rational(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, c*Rational(2, 17) + a/2), Point(c/68 + a, c*Rational(-2, 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(Rational(14, 5), Rational(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(S.Half, 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(S.Half + sqrt(3)/2, S.Half + sqrt(3)/2), 1)
def test_parabola_geom():
a, b = symbols('a b')
p1 = Point(0, 0)
p2 = Point(3, 7)
p3 = Point(0, 4)
p4 = Point(6, 0)
p5 = Point(a, a)
d1 = Line(Point(4, 0), Point(4, 9))
d2 = Line(Point(7, 6), Point(3, 6))
d3 = Line(Point(4, 0), slope=oo)
d4 = Line(Point(7, 6), slope=0)
d5 = Line(Point(b, a), slope=oo)
d6 = Line(Point(a, b), slope=0)
half = S.Half
pa1 = Parabola(None, d2)
pa2 = Parabola(directrix=d1)
pa3 = Parabola(p1, d1)
pa4 = Parabola(p2, d2)
pa5 = Parabola(p2, d4)
pa6 = Parabola(p3, d2)
pa7 = Parabola(p2, d1)
pa8 = Parabola(p4, d1)
pa9 = Parabola(p4, d3)
pa10 = Parabola(p5, d5)
pa11 = Parabola(p5, d6)
d = Line(Point(3, 7), Point(2, 9))
pa12 = Parabola(Point(7, 8), d)
pa12r = Parabola(Point(7, 8).reflect(d), d)
raises(ValueError,
lambda: Parabola(Point(7, 8, 9), Line(Point(6, 7), Point(7, 7))))
raises(ValueError,
lambda: Parabola(Point(0, 2), Line(Point(7, 2), Point(6, 2))))
raises(ValueError, lambda: Parabola(Point(7, 8), Point(3, 8)))
# Basic Stuff
assert pa1.focus == Point(0, 0)
assert pa1.ambient_dimension == S(2)
assert pa2 == pa3
assert pa4 != pa7
assert pa6 != pa7
assert pa6.focus == Point2D(0, 4)
assert pa6.focal_length == 1
assert pa6.p_parameter == -1
assert pa6.vertex == Point2D(0, 5)
assert pa6.eccentricity == 1
assert pa7.focus == Point2D(3, 7)
assert pa7.focal_length == half
assert pa7.p_parameter == -half
assert pa7.vertex == Point2D(7 * half, 7)
assert pa4.focal_length == half
assert pa4.p_parameter == half
assert pa4.vertex == Point2D(3, 13 * half)
assert pa8.focal_length == 1
assert pa8.p_parameter == 1
assert pa8.vertex == Point2D(5, 0)
assert pa4.focal_length == pa5.focal_length
assert pa4.p_parameter == pa5.p_parameter
assert pa4.vertex == pa5.vertex
assert pa4.equation() == pa5.equation()
assert pa8.focal_length == pa9.focal_length
assert pa8.p_parameter == pa9.p_parameter
assert pa8.vertex == pa9.vertex
assert pa8.equation() == pa9.equation()
assert pa10.focal_length == pa11.focal_length == sqrt(
(a - b)**2) / 2 # if a, b real == abs(a - b)/2
assert pa11.vertex == Point(*pa10.vertex[::-1]) == Point(
a, a - sqrt(
(a - b)**2) * sign(a - b) / 2) # change axis x->y, y->x on pa10
aos = pa12.axis_of_symmetry
assert aos == Line(Point(7, 8), Point(5, 7))
assert pa12.directrix == Line(Point(3, 7), Point(2, 9))
assert pa12.directrix.angle_between(aos) == S.Pi / 2
assert pa12.eccentricity == 1
assert pa12.equation(
x, y) == (x - 7)**2 + (y - 8)**2 - (-2 * x - y + 13)**2 / 5
assert pa12.focal_length == 9 * sqrt(5) / 10
assert pa12.focus == Point(7, 8)
assert pa12.p_parameter == 9 * sqrt(5) / 10
assert pa12.vertex == Point2D(S(26) / 5, S(71) / 10)
assert pa12r.focal_length == 9 * sqrt(5) / 10
assert pa12r.focus == Point(-S(1) / 5, S(22) / 5)
assert pa12r.p_parameter == -9 * sqrt(5) / 10
assert pa12r.vertex == Point(S(8) / 5, S(53) / 10)
def test_parabola_intersection():
l1 = Line(Point(1, -2), Point(-1, -2))
l2 = Line(Point(1, 2), Point(-1, 2))
l3 = Line(Point(1, 0), Point(-1, 0))
p1 = Point(0, 0)
p2 = Point(0, -2)
p3 = Point(120, -12)
parabola1 = Parabola(p1, l1)
# parabola with parabola
assert parabola1.intersection(parabola1) == [parabola1]
assert parabola1.intersection(Parabola(
p1, l2)) == [Point2D(-2, 0), Point2D(2, 0)]
assert parabola1.intersection(Parabola(p2, l3)) == [Point2D(0, -1)]
assert parabola1.intersection(Parabola(Point(16, 0),
l1)) == [Point2D(8, 15)]
assert parabola1.intersection(Parabola(Point(
0, 16), l1)) == [Point2D(-6, 8), Point2D(6, 8)]
assert parabola1.intersection(Parabola(p3, l3)) == []
# parabola with point
assert parabola1.intersection(p1) == []
assert parabola1.intersection(Point2D(0, -1)) == [Point2D(0, -1)]
assert parabola1.intersection(Point2D(4, 3)) == [Point2D(4, 3)]
# parabola with line
assert parabola1.intersection(Line(Point2D(-7, 3), Point(
12, 3))) == [Point2D(-4, 3), Point2D(4, 3)]
assert parabola1.intersection(Line(Point(-4, -1),
Point(4, -1))) == [Point(0, -1)]
assert parabola1.intersection(Line(Point(2, 0),
Point(0, -2))) == [Point2D(2, 0)]
raises(
TypeError,
lambda: parabola1.intersection(Line(Point(0, 0, 0), Point(1, 1, 1))))
# parabola with segment
assert parabola1.intersection(Segment2D(
(-4, -5), (4, 3))) == [Point2D(0, -1), Point2D(4, 3)]
assert parabola1.intersection(Segment2D((0, -5),
(0, 6))) == [Point2D(0, -1)]
assert parabola1.intersection(Segment2D((-12, -65), (14, -68))) == []
# parabola with ray
assert parabola1.intersection(Ray2D(
(-4, -5), (4, 3))) == [Point2D(0, -1), Point2D(4, 3)]
assert parabola1.intersection(Ray2D(
(0, 7), (1, 14))) == [Point2D(14 + 2 * sqrt(57), 105 + 14 * sqrt(57))]
assert parabola1.intersection(Ray2D((0, 7), (0, 14))) == []
# parabola with ellipse/circle
assert parabola1.intersection(Circle(
p1, 2)) == [Point2D(-2, 0), Point2D(2, 0)]
assert parabola1.intersection(Circle(
p2, 1)) == [Point2D(0, -1), Point2D(0, -1)]
assert parabola1.intersection(Ellipse(
p2, 2, 1)) == [Point2D(0, -1), Point2D(0, -1)]
assert parabola1.intersection(Ellipse(Point(0, 19), 5, 7)) == []
assert parabola1.intersection(Ellipse((0, 3), 12, 4)) == \
[Point2D(0, -1), Point2D(0, -1), Point2D(-4*sqrt(17)/3, Rational(59, 9)), Point2D(4*sqrt(17)/3, Rational(59, 9))]
# parabola with unsupported type
raises(TypeError, lambda: parabola1.intersection(2))
def test_parabola_geom():
a, b = symbols('a b')
p1 = Point(0, 0)
p2 = Point(3, 7)
p3 = Point(0, 4)
p4 = Point(6, 0)
p5 = Point(a, a)
d1 = Line(Point(4, 0), Point(4, 9))
d2 = Line(Point(7, 6), Point(3, 6))
d3 = Line(Point(4, 0), slope=oo)
d4 = Line(Point(7, 6), slope=0)
d5 = Line(Point(b, a), slope=oo)
d6 = Line(Point(a, b), slope=0)
half = S.Half
pa1 = Parabola(None, d2)
pa2 = Parabola(directrix=d1)
pa3 = Parabola(p1, d1)
pa4 = Parabola(p2, d2)
pa5 = Parabola(p2, d4)
pa6 = Parabola(p3, d2)
pa7 = Parabola(p2, d1)
pa8 = Parabola(p4, d1)
pa9 = Parabola(p4, d3)
pa10 = Parabola(p5, d5)
pa11 = Parabola(p5, d6)
raises(ValueError,
lambda: Parabola(Point(7, 8, 9), Line(Point(6, 7), Point(7, 7))))
raises(NotImplementedError,
lambda: Parabola(Point(7, 8), Line(Point(3, 7), Point(2, 9))))
raises(ValueError,
lambda: Parabola(Point(0, 2), Line(Point(7, 2), Point(6, 2))))
raises(ValueError, lambda: Parabola(Point(7, 8), Point(3, 8)))
# Basic Stuff
assert pa1.focus == Point(0, 0)
assert pa1.ambient_dimension == S(2)
assert pa2 == pa3
assert pa4 != pa7
assert pa6 != pa7
assert pa6.focus == Point2D(0, 4)
assert pa6.focal_length == 1
assert pa6.p_parameter == -1
assert pa6.vertex == Point2D(0, 5)
assert pa6.eccentricity == 1
assert pa7.focus == Point2D(3, 7)
assert pa7.focal_length == half
assert pa7.p_parameter == -half
assert pa7.vertex == Point2D(7 * half, 7)
assert pa4.focal_length == half
assert pa4.p_parameter == half
assert pa4.vertex == Point2D(3, 13 * half)
assert pa8.focal_length == 1
assert pa8.p_parameter == 1
assert pa8.vertex == Point2D(5, 0)
assert pa4.focal_length == pa5.focal_length
assert pa4.p_parameter == pa5.p_parameter
assert pa4.vertex == pa5.vertex
assert pa4.equation() == pa5.equation()
assert pa8.focal_length == pa9.focal_length
assert pa8.p_parameter == pa9.p_parameter
assert pa8.vertex == pa9.vertex
assert pa8.equation() == pa9.equation()
assert pa10.focal_length == pa11.focal_length == sqrt(
(a - b)**2) / 2 # if a, b real == abs(a - b)/2
assert pa11.vertex == Point(*pa10.vertex[::-1]) == Point(
a, a - sqrt(
(a - b)**2) * sign(a - b) / 2) # change axis x->y, y->x on pa10
def test_object_from_equation():
from sympy.abc import x, y, a, b, c, d, e
assert Circle(x**2 + y**2 + 3 * x + 4 * y - 8) == Circle(
Point2D(S(-3) / 2, -2),
sqrt(57) / 2)
assert Circle(x**2 + y**2 + 6 * x + 8 * y + 25) == Circle(
Point2D(-3, -4), 0)
assert Circle(a**2 + b**2 + 6 * a + 8 * b + 25, x='a',
y='b') == Circle(Point2D(-3, -4), 0)
assert Circle(x**2 + y**2 - 25) == Circle(Point2D(0, 0), 5)
assert Circle(x**2 + y**2) == Circle(Point2D(0, 0), 0)
assert Circle(a**2 + b**2, x='a', y='b') == Circle(Point2D(0, 0), 0)
assert Circle(x**2 + y**2 + 6 * x + 8) == Circle(Point2D(-3, 0), 1)
assert Circle(x**2 + y**2 + 6 * y + 8) == Circle(Point2D(0, -3), 1)
assert Circle((x - 1)**2 + y**2 - 9) == Circle(Point2D(1, 0), 3)
assert Circle(6 * (x**2) + 6 * (y**2) + 6 * x + 8 * y - 25) == Circle(
Point2D(Rational(-1, 2), Rational(-2, 3)), 5 * sqrt(7) / 6)
assert Circle(Eq(a**2 + b**2, 25), x='a', y=b) == Circle(Point2D(0, 0), 5)
raises(GeometryError, lambda: Circle(x**2 + y**2 + 3 * x + 4 * y + 26))
raises(GeometryError, lambda: Circle(x**2 + y**2 + 25))
raises(GeometryError, lambda: Circle(a**2 + b**2 + 25, x='a', y='b'))
raises(GeometryError, lambda: Circle(x**2 + 6 * y + 8))
raises(GeometryError, lambda: Circle(6 * (x**2) + 4 *
(y**2) + 6 * x + 8 * y + 25))
raises(ValueError, lambda: Circle(a**2 + b**2 + 3 * a + 4 * b - 8))
# .equation() adds 'real=True' assumption; '==' would fail if assumptions differed
x, y = symbols('x y', real=True)
eq = a * x**2 + a * y**2 + c * x + d * y + e
assert expand(Circle(eq).equation() * a) == eq