def test_invert_complex():
assert invert_complex(x + 3, y, x) == (x, FiniteSet(y - 3))
assert invert_complex(x * 3, y, x) == (x, FiniteSet(y / 3))
assert invert_complex(exp(x), y, x) == (x, imageset(Lambda(n, I * (2 * pi * n + arg(y)) + log(Abs(y))), S.Integers))
assert invert_complex(log(x), y, x) == (x, FiniteSet(exp(y)))
raises(ValueError, lambda: invert_real(S.One, y, x))
raises(ValueError, lambda: invert_complex(x, x, x))
def test_invert_complex():
assert invert_complex(x + 3, y, x) == (x, FiniteSet(y - 3))
assert invert_complex(x * 3, y, x) == (x, FiniteSet(y / 3))
assert invert_complex(exp(x), y, x) == \
(x, imageset(Lambda(n, I*(2*pi*n + arg(y)) + log(Abs(y))), S.Integers))
assert invert_complex(log(x), y, x) == (x, FiniteSet(exp(y)))
raises(ValueError, lambda: invert_real(S.One, y, x))
raises(ValueError, lambda: invert_complex(x, x, x))
def test_invert_real():
x = Dummy(real=True)
n = Symbol('n')
minus_n = Intersection(Interval(-oo, 0), FiniteSet(-n))
plus_n = Intersection(Interval(0, oo), FiniteSet(n))
assert solveset(abs(x) - n, x, S.Reals) == Union(minus_n, plus_n)
n = Symbol('n', real=True)
assert invert_real(x + 3, y, x) == (x, FiniteSet(y - 3))
assert invert_real(x*3, y, x) == (x, FiniteSet(y / 3))
assert invert_real(exp(x), y, x) == (x, FiniteSet(log(y)))
assert invert_real(exp(3*x), y, x) == (x, FiniteSet(log(y) / 3))
assert invert_real(exp(x + 3), y, x) == (x, FiniteSet(log(y) - 3))
assert invert_real(exp(x) + 3, y, x) == (x, FiniteSet(log(y - 3)))
assert invert_real(exp(x)*3, y, x) == (x, FiniteSet(log(y / 3)))
assert invert_real(log(x), y, x) == (x, FiniteSet(exp(y)))
assert invert_real(log(3*x), y, x) == (x, FiniteSet(exp(y) / 3))
assert invert_real(log(x + 3), y, x) == (x, FiniteSet(exp(y) - 3))
minus_y = Intersection(Interval(-oo, 0), FiniteSet(-y))
plus_y = Intersection(Interval(0, oo), FiniteSet(y))
assert invert_real(Abs(x), y, x) == (x, Union(minus_y, plus_y))
assert invert_real(2**x, y, x) == (x, FiniteSet(log(y)/log(2)))
assert invert_real(2**exp(x), y, x) == (x, FiniteSet(log(log(y)/log(2))))
assert invert_real(x**2, y, x) == (x, FiniteSet(sqrt(y), -sqrt(y)))
assert invert_real(x**Rational(1, 2), y, x) == (x, FiniteSet(y**2))
raises(ValueError, lambda: invert_real(x, x, x))
raises(ValueError, lambda: invert_real(x**pi, y, x))
raises(ValueError, lambda: invert_real(S.One, y, x))
assert invert_real(x**31 + x, y, x) == (x**31 + x, FiniteSet(y))
y_1 = Intersection(Interval(-1, oo), FiniteSet(y - 1))
y_2 = Intersection(Interval(-oo, -1), FiniteSet(-y - 1))
assert invert_real(Abs(x**31 + x + 1), y, x) == (x**31 + x,
Union(y_1, y_2))
assert invert_real(sin(x), y, x) == \
(x, imageset(Lambda(n, n*pi + (-1)**n*asin(y)), S.Integers))
assert invert_real(sin(exp(x)), y, x) == \
(x, imageset(Lambda(n, log((-1)**n*asin(y) + n*pi)), S.Integers))
assert invert_real(csc(x), y, x) == \
(x, imageset(Lambda(n, n*pi + (-1)**n*acsc(y)), S.Integers))
assert invert_real(csc(exp(x)), y, x) == \
(x, imageset(Lambda(n, log((-1)**n*acsc(y) + n*pi)), S.Integers))
assert invert_real(cos(x), y, x) == \
(x, Union(imageset(Lambda(n, 2*n*pi + acos(y)), S.Integers), \
imageset(Lambda(n, 2*n*pi - acos(y)), S.Integers)))
assert invert_real(cos(exp(x)), y, x) == \
(x, Union(imageset(Lambda(n, log(2*n*pi + acos(y))), S.Integers), \
imageset(Lambda(n, log(2*n*pi - acos(y))), S.Integers)))
assert invert_real(sec(x), y, x) == \
(x, Union(imageset(Lambda(n, 2*n*pi + asec(y)), S.Integers), \
imageset(Lambda(n, 2*n*pi - asec(y)), S.Integers)))
assert invert_real(sec(exp(x)), y, x) == \
(x, Union(imageset(Lambda(n, log(2*n*pi + asec(y))), S.Integers), \
imageset(Lambda(n, log(2*n*pi - asec(y))), S.Integers)))
assert invert_real(tan(x), y, x) == \
(x, imageset(Lambda(n, n*pi + atan(y)), S.Integers))
assert invert_real(tan(exp(x)), y, x) == \
(x, imageset(Lambda(n, log(n*pi + atan(y))), S.Integers))
assert invert_real(cot(x), y, x) == \
(x, imageset(Lambda(n, n*pi + acot(y)), S.Integers))
assert invert_real(cot(exp(x)), y, x) == \
(x, imageset(Lambda(n, log(n*pi + acot(y))), S.Integers))
assert invert_real(tan(tan(x)), y, x) == \
(tan(x), imageset(Lambda(n, n*pi + atan(y)), S.Integers))
x = Symbol('x', positive=True)
assert invert_real(x**pi, y, x) == (x, FiniteSet(y**(1/pi)))
# Test for ``set_h`` containing information about the domain
n = Dummy('n')
x = Symbol('x')
h1 = Intersection(Interval(-3, oo), FiniteSet(a + b - 3),
imageset(Lambda(n, -n + a - 3), Interval(-oo, 0)))
h2 = Intersection(Interval(-oo, -3), FiniteSet(-a + b - 3),
imageset(Lambda(n, n - a - 3), Interval(0, oo)))
h3 = Intersection(Interval(-3, oo), FiniteSet(a - b - 3),
imageset(Lambda(n, -n + a - 3), Interval(0, oo)))
h4 = Intersection(Interval(-oo, -3), FiniteSet(-a - b - 3),
imageset(Lambda(n, n - a - 3), Interval(-oo, 0)))
assert invert_real(Abs(Abs(x + 3) - a) - b, 0, x) == (x, Union(h1, h2, h3, h4))
def test_invert_real():
x = Symbol('x', real=True)
y = Symbol('y')
n = Symbol('n')
def ireal(x, s=S.Reals):
return Intersection(s, x)
minus_n = Intersection(Interval(-oo, 0), FiniteSet(-n))
plus_n = Intersection(Interval(0, oo), FiniteSet(n))
assert solveset(abs(x) - n, x, S.Reals) == Union(minus_n, plus_n)
assert invert_real(exp(x), y, x) == (x, ireal(FiniteSet(log(y))))
y = Symbol('y', positive=True)
n = Symbol('n', real=True)
assert invert_real(x + 3, y, x) == (x, FiniteSet(y - 3))
assert invert_real(x * 3, y, x) == (x, FiniteSet(y / 3))
assert invert_real(exp(x), y, x) == (x, FiniteSet(log(y)))
assert invert_real(exp(3 * x), y, x) == (x, FiniteSet(log(y) / 3))
assert invert_real(exp(x + 3), y, x) == (x, FiniteSet(log(y) - 3))
assert invert_real(exp(x) + 3, y, x) == (x, ireal(FiniteSet(log(y - 3))))
assert invert_real(exp(x) * 3, y, x) == (x, FiniteSet(log(y / 3)))
assert invert_real(log(x), y, x) == (x, FiniteSet(exp(y)))
assert invert_real(log(3 * x), y, x) == (x, FiniteSet(exp(y) / 3))
assert invert_real(log(x + 3), y, x) == (x, FiniteSet(exp(y) - 3))
minus_y = Intersection(Interval(-oo, 0), FiniteSet(-y))
plus_y = Intersection(Interval(0, oo), FiniteSet(y))
assert invert_real(Abs(x), y, x) == (x, Union(minus_y, plus_y))
assert invert_real(2**x, y, x) == (x, FiniteSet(log(y) / log(2)))
assert invert_real(2**exp(x), y,
x) == (x, ireal(FiniteSet(log(log(y) / log(2)))))
assert invert_real(x**2, y, x) == (x, FiniteSet(sqrt(y), -sqrt(y)))
assert invert_real(x**Rational(1, 2), y, x) == (x, FiniteSet(y**2))
raises(ValueError, lambda: invert_real(x, x, x))
raises(ValueError, lambda: invert_real(x**pi, y, x))
raises(ValueError, lambda: invert_real(S.One, y, x))
assert invert_real(x**31 + x, y, x) == (x**31 + x, FiniteSet(y))
y_1 = Intersection(Interval(-1, oo), FiniteSet(y - 1))
y_2 = Intersection(Interval(-oo, -1), FiniteSet(-y - 1))
assert invert_real(Abs(x**31 + x + 1), y,
x) == (x**31 + x, Union(y_1, y_2))
assert invert_real(sin(x), y, x) == \
(x, imageset(Lambda(n, n*pi + (-1)**n*asin(y)), S.Integers))
assert invert_real(sin(exp(x)), y, x) == \
(x, imageset(Lambda(n, log((-1)**n*asin(y) + n*pi)), S.Integers))
assert invert_real(csc(x), y, x) == \
(x, imageset(Lambda(n, n*pi + (-1)**n*acsc(y)), S.Integers))
assert invert_real(csc(exp(x)), y, x) == \
(x, imageset(Lambda(n, log((-1)**n*acsc(y) + n*pi)), S.Integers))
assert invert_real(cos(x), y, x) == \
(x, Union(imageset(Lambda(n, 2*n*pi + acos(y)), S.Integers), \
imageset(Lambda(n, 2*n*pi - acos(y)), S.Integers)))
assert invert_real(cos(exp(x)), y, x) == \
(x, Union(imageset(Lambda(n, log(2*n*pi + acos(y))), S.Integers), \
imageset(Lambda(n, log(2*n*pi - acos(y))), S.Integers)))
assert invert_real(sec(x), y, x) == \
(x, Union(imageset(Lambda(n, 2*n*pi + asec(y)), S.Integers), \
imageset(Lambda(n, 2*n*pi - asec(y)), S.Integers)))
assert invert_real(sec(exp(x)), y, x) == \
(x, Union(imageset(Lambda(n, log(2*n*pi + asec(y))), S.Integers), \
imageset(Lambda(n, log(2*n*pi - asec(y))), S.Integers)))
assert invert_real(tan(x), y, x) == \
(x, imageset(Lambda(n, n*pi + atan(y)), S.Integers))
assert invert_real(tan(exp(x)), y, x) == \
(x, imageset(Lambda(n, log(n*pi + atan(y))), S.Integers))
assert invert_real(cot(x), y, x) == \
(x, imageset(Lambda(n, n*pi + acot(y)), S.Integers))
assert invert_real(cot(exp(x)), y, x) == \
(x, imageset(Lambda(n, log(n*pi + acot(y))), S.Integers))
assert invert_real(tan(tan(x)), y, x) == \
(tan(x), imageset(Lambda(n, n*pi + atan(y)), S.Integers))
x = Symbol('x', positive=True)
assert invert_real(x**pi, y, x) == (x, FiniteSet(y**(1 / pi)))
# Test for ``set_h`` containing information about the domain
n = Dummy('n')
x = Symbol('x')
h1 = Intersection(Interval(-oo, -3), FiniteSet(-a + b - 3),
imageset(Lambda(n, n - a - 3), Interval(0, oo)))
h2 = Intersection(Interval(-3, oo), FiniteSet(a - b - 3),
imageset(Lambda(n, -n + a - 3), Interval(0, oo)))
assert invert_real(Abs(Abs(x + 3) - a) - b, 0, x) == (x, Union(h1, h2))
def test_invert_real():
x = Dummy(real=True)
n = Symbol("n")
d = Dummy()
assert solveset(abs(x) - n, x) == solveset(abs(x) - d, x) == EmptySet()
n = Symbol("n", real=True)
assert invert_real(x + 3, y, x) == (x, FiniteSet(y - 3))
assert invert_real(x * 3, y, x) == (x, FiniteSet(y / 3))
assert invert_real(exp(x), y, x) == (x, FiniteSet(log(y)))
assert invert_real(exp(3 * x), y, x) == (x, FiniteSet(log(y) / 3))
assert invert_real(exp(x + 3), y, x) == (x, FiniteSet(log(y) - 3))
assert invert_real(exp(x) + 3, y, x) == (x, FiniteSet(log(y - 3)))
assert invert_real(exp(x) * 3, y, x) == (x, FiniteSet(log(y / 3)))
assert invert_real(log(x), y, x) == (x, FiniteSet(exp(y)))
assert invert_real(log(3 * x), y, x) == (x, FiniteSet(exp(y) / 3))
assert invert_real(log(x + 3), y, x) == (x, FiniteSet(exp(y) - 3))
assert invert_real(Abs(x), y, x) == (x, FiniteSet(-y, y))
assert invert_real(2 ** x, y, x) == (x, FiniteSet(log(y) / log(2)))
assert invert_real(2 ** exp(x), y, x) == (x, FiniteSet(log(log(y) / log(2))))
assert invert_real(x ** 2, y, x) == (x, FiniteSet(sqrt(y), -sqrt(y)))
assert invert_real(x ** Rational(1, 2), y, x) == (x, FiniteSet(y ** 2))
raises(ValueError, lambda: invert_real(x, x, x))
raises(ValueError, lambda: invert_real(x ** pi, y, x))
raises(ValueError, lambda: invert_real(S.One, y, x))
assert invert_real(x ** 31 + x, y, x) == (x ** 31 + x, FiniteSet(y))
assert invert_real(Abs(x ** 31 + x + 1), y, x) == (x ** 31 + x, FiniteSet(-y - 1, y - 1))
assert invert_real(tan(x), y, x) == (x, imageset(Lambda(n, n * pi + atan(y)), S.Integers))
assert invert_real(tan(exp(x)), y, x) == (x, imageset(Lambda(n, log(n * pi + atan(y))), S.Integers))
assert invert_real(cot(x), y, x) == (x, imageset(Lambda(n, n * pi + acot(y)), S.Integers))
assert invert_real(cot(exp(x)), y, x) == (x, imageset(Lambda(n, log(n * pi + acot(y))), S.Integers))
assert invert_real(tan(tan(x)), y, x) == (tan(x), imageset(Lambda(n, n * pi + atan(y)), S.Integers))
x = Symbol("x", positive=True)
assert invert_real(x ** pi, y, x) == (x, FiniteSet(y ** (1 / pi)))
def test_invert_real():
x = Symbol('x', real=True)
x = Dummy(real=True)
n = Symbol('n')
d = Dummy()
assert solveset(abs(x) - n, x) == solveset(abs(x) - d, x) == EmptySet()
n = Symbol('n', real=True)
assert invert_real(x + 3, y, x) == (x, FiniteSet(y - 3))
assert invert_real(x * 3, y, x) == (x, FiniteSet(y / 3))
assert invert_real(exp(x), y, x) == (x, FiniteSet(log(y)))
assert invert_real(exp(3 * x), y, x) == (x, FiniteSet(log(y) / 3))
assert invert_real(exp(x + 3), y, x) == (x, FiniteSet(log(y) - 3))
assert invert_real(exp(x) + 3, y, x) == (x, FiniteSet(log(y - 3)))
assert invert_real(exp(x) * 3, y, x) == (x, FiniteSet(log(y / 3)))
assert invert_real(log(x), y, x) == (x, FiniteSet(exp(y)))
assert invert_real(log(3 * x), y, x) == (x, FiniteSet(exp(y) / 3))
assert invert_real(log(x + 3), y, x) == (x, FiniteSet(exp(y) - 3))
assert invert_real(Abs(x), y, x) == (x, FiniteSet(-y, y))
assert invert_real(2**x, y, x) == (x, FiniteSet(log(y) / log(2)))
assert invert_real(2**exp(x), y, x) == (x, FiniteSet(log(log(y) / log(2))))
assert invert_real(x**2, y, x) == (x, FiniteSet(sqrt(y), -sqrt(y)))
assert invert_real(x**Rational(1, 2), y, x) == (x, FiniteSet(y**2))
raises(ValueError, lambda: invert_real(x, x, x))
raises(ValueError, lambda: invert_real(x**pi, y, x))
raises(ValueError, lambda: invert_real(S.One, y, x))
assert invert_real(x**31 + x, y, x) == (x**31 + x, FiniteSet(y))
assert invert_real(Abs(x**31 + x + 1), y,
x) == (x**31 + x, FiniteSet(-y - 1, y - 1))
assert invert_real(tan(x), y, x) == \
(x, imageset(Lambda(n, n*pi + atan(y)), S.Integers))
assert invert_real(tan(exp(x)), y, x) == \
(x, imageset(Lambda(n, log(n*pi + atan(y))), S.Integers))
assert invert_real(cot(x), y, x) == \
(x, imageset(Lambda(n, n*pi + acot(y)), S.Integers))
assert invert_real(cot(exp(x)), y, x) == \
(x, imageset(Lambda(n, log(n*pi + acot(y))), S.Integers))
assert invert_real(tan(tan(x)), y, x) == \
(tan(x), imageset(Lambda(n, n*pi + atan(y)), S.Integers))
x = Symbol('x', positive=True)
assert invert_real(x**pi, y, x) == (x, FiniteSet(y**(1 / pi)))
