def test_finally():
try:
with assuming(Q.integer(x)):
1/0
except ZeroDivisionError:
pass
assert not ask(Q.integer(x))
def test_float_1():
z = 1.0
assert ask(Q.commutative(z)) == True
assert ask(Q.integer(z)) == True
assert ask(Q.rational(z)) == True
assert ask(Q.real(z)) == True
assert ask(Q.complex(z)) == True
assert ask(Q.irrational(z)) == False
assert ask(Q.imaginary(z)) == False
assert ask(Q.positive(z)) == True
assert ask(Q.negative(z)) == False
assert ask(Q.even(z)) == False
assert ask(Q.odd(z)) == True
assert ask(Q.bounded(z)) == True
assert ask(Q.infinitesimal(z)) == False
assert ask(Q.prime(z)) == False
assert ask(Q.composite(z)) == True
z = 7.2123
assert ask(Q.commutative(z)) == True
assert ask(Q.integer(z)) == False
assert ask(Q.rational(z)) == True
assert ask(Q.real(z)) == True
assert ask(Q.complex(z)) == True
assert ask(Q.irrational(z)) == False
assert ask(Q.imaginary(z)) == False
assert ask(Q.positive(z)) == True
assert ask(Q.negative(z)) == False
assert ask(Q.even(z)) == False
assert ask(Q.odd(z)) == False
assert ask(Q.bounded(z)) == True
assert ask(Q.infinitesimal(z)) == False
assert ask(Q.prime(z)) == False
assert ask(Q.composite(z)) == False
def Pow(expr, assumptions):
"""
Integer**Integer -> !Prime
"""
if expr.is_number:
return AskPrimeHandler._number(expr, assumptions)
if ask(Q.integer(expr.exp), assumptions) and ask(Q.integer(expr.base), assumptions):
return False
def test_custom_context():
"""Test ask with custom assumptions context"""
x = symbols('x')
assert ask(Q.integer(x)) == None
local_context = AssumptionsContext()
local_context.add(Q.integer(x))
assert ask(Q.integer(x), context = local_context) == True
assert ask(Q.integer(x)) == None
def test_remove_safe():
global_assumptions.add(Q.integer(x))
with assuming():
assert ask(Q.integer(x))
global_assumptions.remove(Q.integer(x))
assert not ask(Q.integer(x))
assert ask(Q.integer(x))
global_assumptions.clear() # for the benefit of other tests
def test_global():
"""Test ask with global assumptions"""
x = symbols('x')
assert ask(Q.integer(x)) == None
global_assumptions.add(Q.integer(x))
assert ask(Q.integer(x)) == True
global_assumptions.clear()
assert ask(Q.integer(x)) == None
def Pow(expr, assumptions):
"""
Real**Integer -> Real
Positive**Real -> Real
Real**(Integer/Even) -> Real if base is nonnegative
Real**(Integer/Odd) -> Real
Imaginary**(Integer/Even) -> Real
Imaginary**(Integer/Odd) -> not Real
Imaginary**Real -> ? since Real could be 0 (giving real) or 1 (giving imaginary)
b**Imaginary -> Real if log(b) is imaginary and b != 0 and exponent != integer multiple of I*pi/log(b)
Real**Real -> ? e.g. sqrt(-1) is imaginary and sqrt(2) is not
"""
if expr.is_number:
return AskRealHandler._number(expr, assumptions)
if expr.base.func == exp:
if ask(Q.imaginary(expr.base.args[0]), assumptions):
if ask(Q.imaginary(expr.exp), assumptions):
return True
# If the i = (exp's arg)/(I*pi) is an integer or half-integer
# multiple of I*pi then 2*i will be an integer. In addition,
# exp(i*I*pi) = (-1)**i so the overall realness of the expr
# can be determined by replacing exp(i*I*pi) with (-1)**i.
i = expr.base.args[0]/I/pi
if ask(Q.integer(2*i), assumptions):
return ask(Q.real(((-1)**i)**expr.exp), assumptions)
return
if ask(Q.imaginary(expr.base), assumptions):
if ask(Q.integer(expr.exp), assumptions):
odd = ask(Q.odd(expr.exp), assumptions)
if odd is not None:
return not odd
return
if ask(Q.imaginary(expr.exp), assumptions):
imlog = ask(Q.imaginary(log(expr.base)), assumptions)
if imlog is not None:
# I**i -> real, log(I) is imag;
# (2*I)**i -> complex, log(2*I) is not imag
return imlog
if ask(Q.real(expr.base), assumptions):
if ask(Q.real(expr.exp), assumptions):
if expr.exp.is_Rational and \
ask(Q.even(expr.exp.q), assumptions):
return ask(Q.positive(expr.base), assumptions)
elif ask(Q.integer(expr.exp), assumptions):
return True
elif ask(Q.positive(expr.base), assumptions):
return True
elif ask(Q.negative(expr.base), assumptions):
return False
def test_I():
I = S.ImaginaryUnit
z = I
assert ask(Q.commutative(z)) == True
assert ask(Q.integer(z)) == False
assert ask(Q.rational(z)) == False
assert ask(Q.real(z)) == False
assert ask(Q.complex(z)) == True
assert ask(Q.irrational(z)) == False
assert ask(Q.imaginary(z)) == True
assert ask(Q.positive(z)) == False
assert ask(Q.negative(z)) == False
assert ask(Q.even(z)) == False
assert ask(Q.odd(z)) == False
assert ask(Q.bounded(z)) == True
assert ask(Q.infinitesimal(z)) == False
assert ask(Q.prime(z)) == False
assert ask(Q.composite(z)) == False
z = 1 + I
assert ask(Q.commutative(z)) == True
assert ask(Q.integer(z)) == False
assert ask(Q.rational(z)) == False
assert ask(Q.real(z)) == False
assert ask(Q.complex(z)) == True
assert ask(Q.irrational(z)) == False
assert ask(Q.imaginary(z)) == False
assert ask(Q.positive(z)) == False
assert ask(Q.negative(z)) == False
assert ask(Q.even(z)) == False
assert ask(Q.odd(z)) == False
assert ask(Q.bounded(z)) == True
assert ask(Q.infinitesimal(z)) == False
assert ask(Q.prime(z)) == False
assert ask(Q.composite(z)) == False
z = I*(1+I)
assert ask(Q.commutative(z)) == True
assert ask(Q.integer(z)) == False
assert ask(Q.rational(z)) == False
assert ask(Q.real(z)) == False
assert ask(Q.complex(z)) == True
assert ask(Q.irrational(z)) == False
assert ask(Q.imaginary(z)) == False
assert ask(Q.positive(z)) == False
assert ask(Q.negative(z)) == False
assert ask(Q.even(z)) == False
assert ask(Q.odd(z)) == False
assert ask(Q.bounded(z)) == True
assert ask(Q.infinitesimal(z)) == False
assert ask(Q.prime(z)) == False
assert ask(Q.composite(z)) == False
def Pow(expr, assumptions):
"""
Imaginary**Odd -> Imaginary
Imaginary**Even -> Real
b**Imaginary -> !Imaginary if exponent is an integer multiple of I*pi/log(b)
Imaginary**Real -> ?
Positive**Real -> Real
Negative**Integer -> Real
Negative**(Integer/2) -> Imaginary
Negative**Real -> not Imaginary if exponent is not Rational
"""
if expr.is_number:
return AskImaginaryHandler._number(expr, assumptions)
if expr.base.func == exp:
if ask(Q.imaginary(expr.base.args[0]), assumptions):
if ask(Q.imaginary(expr.exp), assumptions):
return False
i = expr.base.args[0]/I/pi
if ask(Q.integer(2*i), assumptions):
return ask(Q.imaginary(((-1)**i)**expr.exp), assumptions)
if ask(Q.imaginary(expr.base), assumptions):
if ask(Q.integer(expr.exp), assumptions):
odd = ask(Q.odd(expr.exp), assumptions)
if odd is not None:
return odd
return
if ask(Q.imaginary(expr.exp), assumptions):
imlog = ask(Q.imaginary(log(expr.base)), assumptions)
if imlog is not None:
return False # I**i -> real; (2*I)**i -> complex ==> not imaginary
if ask(Q.real(expr.base) & Q.real(expr.exp), assumptions):
if ask(Q.positive(expr.base), assumptions):
return False
else:
rat = ask(Q.rational(expr.exp), assumptions)
if not rat:
return rat
if ask(Q.integer(expr.exp), assumptions):
return False
else:
half = ask(Q.integer(2*expr.exp), assumptions)
if half:
return ask(Q.negative(expr.base), assumptions)
return half
def MatPow(expr, assumptions):
# only for integer powers
base, exp = expr.args
int_exp = ask(Q.integer(exp), assumptions)
if int_exp:
return ask(Q.unitary(base), assumptions)
return None
def test_negative():
x, y = symbols('x,y')
assert ask(Q.negative(x), Q.negative(x)) == True
assert ask(Q.negative(x), Q.positive(x)) == False
assert ask(Q.negative(x), ~Q.real(x)) == False
assert ask(Q.negative(x), Q.prime(x)) == False
assert ask(Q.negative(x), ~Q.prime(x)) == None
assert ask(Q.negative(-x), Q.positive(x)) == True
assert ask(Q.negative(-x), ~Q.positive(x)) == None
assert ask(Q.negative(-x), Q.negative(x)) == False
assert ask(Q.negative(-x), Q.positive(x)) == True
assert ask(Q.negative(x-1), Q.negative(x)) == True
assert ask(Q.negative(x+y)) == None
assert ask(Q.negative(x+y), Q.negative(x)) == None
assert ask(Q.negative(x+y), Q.negative(x) & Q.negative(y)) == True
assert ask(Q.negative(x**2)) == None
assert ask(Q.negative(x**2), Q.real(x)) == False
assert ask(Q.negative(x**1.4), Q.real(x)) == None
assert ask(Q.negative(x*y)) == None
assert ask(Q.negative(x*y), Q.positive(x) & Q.positive(y)) == False
assert ask(Q.negative(x*y), Q.positive(x) & Q.negative(y)) == True
assert ask(Q.negative(x*y), Q.complex(x) & Q.complex(y)) == None
assert ask(Q.negative(x**y)) == None
assert ask(Q.negative(x**y), Q.negative(x) & Q.even(y)) == False
assert ask(Q.negative(x**y), Q.negative(x) & Q.odd(y)) == True
assert ask(Q.negative(x**y), Q.positive(x) & Q.integer(y)) == False
assert ask(Q.negative(Abs(x))) == False
def Pow(expr, assumptions):
"""
Imaginary**integer -> Imaginary if integer % 2 == 1
Imaginary**integer -> real if integer % 2 == 0
Imaginary**Imaginary -> ?
Imaginary**Real -> ?
"""
if expr.is_number:
return AskImaginaryHandler._number(expr, assumptions)
if ask(Q.imaginary(expr.base), assumptions):
if ask(Q.real(expr.exp), assumptions):
if ask(Q.odd(expr.exp), assumptions):
return True
elif ask(Q.even(expr.exp), assumptions):
return False
elif ask(Q.real(expr.base), assumptions):
if ask(Q.real(expr.exp), assumptions):
if expr.exp.is_Rational and \
ask(Q.even(expr.exp.q), assumptions):
return ask(Q.negative(expr.base),assumptions)
elif ask(Q.integer(expr.exp), assumptions):
return False
elif ask(Q.positive(expr.base), assumptions):
return False
elif ask(Q.negative(expr.base), assumptions):
return True
def MatPow(expr, assumptions):
# only for integer powers
base, exp = expr.args
int_exp = ask(Q.integer(exp), assumptions)
if int_exp and ask(~Q.negative(exp), assumptions):
return ask(Q.fullrank(base), assumptions)
return None
def Mul(expr, assumptions):
"""
Integer*Integer -> Integer
Integer*Irrational -> !Integer
Odd/Even -> !Integer
Integer*Rational -> ?
"""
if expr.is_number:
return AskIntegerHandler._number(expr, assumptions)
_output = True
for arg in expr.args:
if not ask(Q.integer(arg), assumptions):
if arg.is_Rational:
if arg.q == 2:
return ask(Q.even(2*expr), assumptions)
if ~(arg.q & 1):
return None
elif ask(Q.irrational(arg), assumptions):
if _output:
_output = False
else:
return
else:
return
else:
return _output
def Basic(expr, assumptions):
_integer = ask(Q.integer(expr), assumptions)
if _integer:
_even = ask(Q.even(expr), assumptions)
if _even is None: return None
return not _even
return _integer
def Mul(expr, assumptions):
"""
Even * Integer -> Even
Even * Odd -> Even
Integer * Odd -> ?
Odd * Odd -> Odd
"""
if expr.is_number:
return AskEvenHandler._number(expr, assumptions)
even, odd, irrational = False, 0, False
for arg in expr.args:
# check for all integers and at least one even
if ask(Q.integer(arg), assumptions):
if ask(Q.even(arg), assumptions):
even = True
elif ask(Q.odd(arg), assumptions):
odd += 1
elif ask(Q.irrational(arg), assumptions):
# one irrational makes the result False
# two makes it undefined
if irrational:
break
irrational = True
else:
break
else:
if irrational:
return False
if even:
return True
if odd == len(expr.args):
return False
def refine_exp(expr, assumptions):
"""
Handler for exponential function.
>>> from sympy import Symbol, Q, exp, I, pi
>>> from sympy.assumptions.refine import refine_exp
>>> from sympy.abc import x
>>> refine_exp(exp(pi*I*2*x), Q.real(x))
>>> refine_exp(exp(pi*I*2*x), Q.integer(x))
1
"""
arg = expr.args[0]
if arg.is_Mul:
coeff = arg.as_coefficient(S.Pi*S.ImaginaryUnit)
if coeff:
if ask(Q.integer(2*coeff), assumptions):
if ask(Q.even(coeff), assumptions):
return S.One
elif ask(Q.odd(coeff), assumptions):
return S.NegativeOne
elif ask(Q.even(coeff + S.Half), assumptions):
return -S.ImaginaryUnit
elif ask(Q.odd(coeff + S.Half), assumptions):
return S.ImaginaryUnit
def Pow(expr, assumptions):
"""
Real**Integer -> Real
Positive**Real -> Real
Real**(Integer/Even) -> Real if base is nonnegative
Real**(Integer/Odd) -> Real
Real**Imaginary -> ?
Imaginary**Real -> ?
Real**Real -> ?
"""
if expr.is_number:
return AskRealHandler._number(expr, assumptions)
if ask(Q.imaginary(expr.base), assumptions):
if ask(Q.real(expr.exp), assumptions):
if ask(Q.odd(expr.exp), assumptions):
return False
elif ask(Q.even(expr.exp), assumptions):
return True
elif ask(Q.real(expr.base), assumptions):
if ask(Q.real(expr.exp), assumptions):
if expr.exp.is_Rational and \
ask(Q.even(expr.exp.q), assumptions):
return ask(Q.positive(expr.base), assumptions)
elif ask(Q.integer(expr.exp), assumptions):
return True
elif ask(Q.positive(expr.base), assumptions):
return True
elif ask(Q.negative(expr.base), assumptions):
return False
def Pow(expr, assumptions):
"""
Imaginary**integer/odd -> Imaginary
Imaginary**integer/even -> Real if integer % 2 == 0
b**Imaginary -> !Imaginary if exponent is an integer multiple of I*pi/log(b)
Imaginary**Real -> ?
Negative**even root -> Imaginary
Negative**odd root -> Real
Negative**Real -> Imaginary
Real**Integer -> Real
Real**Positive -> Real
"""
if expr.is_number:
return AskImaginaryHandler._number(expr, assumptions)
if expr.base.func == C.exp:
if ask(Q.imaginary(expr.base.args[0]), assumptions):
if ask(Q.imaginary(expr.exp), assumptions):
return False
i = expr.base.args[0]/I/pi
if ask(Q.integer(2*i), assumptions):
return ask(Q.imaginary(((-1)**i)**expr.exp), assumptions)
if ask(Q.imaginary(expr.base), assumptions):
if ask(Q.integer(expr.exp), assumptions):
odd = ask(Q.odd(expr.exp), assumptions)
if odd is not None:
return odd
return
if ask(Q.imaginary(expr.exp), assumptions):
imlog = ask(Q.imaginary(C.log(expr.base)), assumptions)
if imlog is not None:
return False # I**i -> real; (2*I)**i -> complex ==> not imaginary
if ask(Q.real(expr.base), assumptions):
if ask(Q.real(expr.exp), assumptions):
if ask(Q.rational(expr.exp) & Q.even(denom(expr.exp)), assumptions):
return ask(Q.negative(expr.base), assumptions)
elif ask(Q.integer(expr.exp), assumptions):
return False
elif ask(Q.positive(expr.base), assumptions):
return False
elif ask(Q.negative(expr.base), assumptions):
return True
def Mul(expr, assumptions):
if expr.is_number:
return AskPrimeHandler._number(expr, assumptions)
for arg in expr.args:
if not ask(Q.integer(arg), assumptions):
return None
for arg in expr.args:
if arg.is_number and arg.is_composite:
return False
def MatPow(expr, assumptions):
# only for integer powers
base, exp = expr.args
int_exp = ask(Q.integer(exp), assumptions)
if not int_exp:
return None
if exp.is_negative == False:
return ask(Q.integer_elements(base), assumptions)
return None
def Pow(expr, assumptions):
"""
Hermitian**Integer -> Hermitian
"""
if expr.is_number:
return AskRealHandler._number(expr, assumptions)
if ask(Q.hermitian(expr.base), assumptions):
if ask(Q.integer(expr.exp), assumptions):
return True
def test_real():
x, y = symbols('x,y')
assert ask(Q.real(x)) == None
assert ask(Q.real(x), Q.real(x)) == True
assert ask(Q.real(x), Q.nonzero(x)) == True
assert ask(Q.real(x), Q.positive(x)) == True
assert ask(Q.real(x), Q.negative(x)) == True
assert ask(Q.real(x), Q.integer(x)) == True
assert ask(Q.real(x), Q.even(x)) == True
assert ask(Q.real(x), Q.prime(x)) == True
assert ask(Q.real(x/sqrt(2)), Q.real(x)) == True
assert ask(Q.real(x/sqrt(-2)), Q.real(x)) == False
I = S.ImaginaryUnit
assert ask(Q.real(x+1), Q.real(x)) == True
assert ask(Q.real(x+I), Q.real(x)) == False
assert ask(Q.real(x+I), Q.complex(x)) == None
assert ask(Q.real(2*x), Q.real(x)) == True
assert ask(Q.real(I*x), Q.real(x)) == False
assert ask(Q.real(I*x), Q.imaginary(x)) == True
assert ask(Q.real(I*x), Q.complex(x)) == None
assert ask(Q.real(x**2), Q.real(x)) == True
assert ask(Q.real(sqrt(x)), Q.negative(x)) == False
assert ask(Q.real(x**y), Q.real(x) & Q.integer(y)) == True
assert ask(Q.real(x**y), Q.real(x) & Q.real(y)) == None
assert ask(Q.real(x**y), Q.positive(x) & Q.real(y)) == True
# trigonometric functions
assert ask(Q.real(sin(x))) == None
assert ask(Q.real(cos(x))) == None
assert ask(Q.real(sin(x)), Q.real(x)) == True
assert ask(Q.real(cos(x)), Q.real(x)) == True
# exponential function
assert ask(Q.real(exp(x))) == None
assert ask(Q.real(exp(x)), Q.real(x)) == True
assert ask(Q.real(x + exp(x)), Q.real(x)) == True
# Q.complexes
assert ask(Q.real(re(x))) == True
assert ask(Q.real(im(x))) == True
def Mul(expr, assumptions):
if expr.is_number:
return AskPrimeHandler._number(expr, assumptions)
for arg in expr.args:
if ask(Q.integer(arg), assumptions):
pass
else: break
else:
# a product of integers can't be a prime
return False
def Basic(expr, assumptions):
_positive = ask(Q.positive(expr), assumptions)
if _positive:
_integer = ask(Q.integer(expr), assumptions)
if _integer:
_prime = ask(Q.prime(expr), assumptions)
if _prime is None: return
return not _prime
else: return _integer
else: return _positive
def Pow(expr, assumptions):
if expr.is_number:
return AskEvenHandler._number(expr, assumptions)
if ask(Q.integer(expr.exp), assumptions):
if ask(Q.positive(expr.exp), assumptions):
return ask(Q.even(expr.base), assumptions)
elif ask(~Q.negative(expr.exp) & Q.odd(expr.base), assumptions):
return False
elif expr.base is S.NegativeOne:
return False
def MatPow(expr, assumptions):
# only for integer powers
base, exp = expr.args
int_exp = ask(Q.integer(exp), assumptions)
if not int_exp:
return None
non_negative = ask(~Q.negative(exp), assumptions)
if (non_negative or non_negative == False
and ask(Q.invertible(base), assumptions)):
return ask(Q.complex_elements(base), assumptions)
return None
def Pow(expr, assumptions):
"""
Rational ** Integer -> Rational
Irrational ** Rational -> Irrational
Rational ** Irrational -> ?
"""
if ask(Q.integer(expr.exp), assumptions):
return ask(Q.rational(expr.base), assumptions)
elif ask(Q.rational(expr.exp), assumptions):
if ask(Q.prime(expr.base), assumptions):
return False
def Mul(expr, assumptions):
if expr.is_number:
return AskPrimeHandler._number(expr, assumptions)
for arg in expr.args:
if ask(Q.integer(arg), assumptions):
pass
else:
break
else:
# a product of integers can't be a prime
return False
def _(expr, assumptions):
# only for integer powers
base, exp = expr.args
int_exp = ask(Q.integer(exp), assumptions)
if not int_exp:
return None
non_negative = ask(~Q.negative(exp), assumptions)
if (non_negative
or non_negative == False and ask(Q.invertible(base), assumptions)):
return ask(Q.diagonal(base), assumptions)
return None
def Pow(expr, assumptions):
"""
Rational ** Integer -> Rational
Irrational ** Rational -> Irrational
Rational ** Irrational -> ?
"""
if ask(Q.integer(expr.exp), assumptions):
return ask(Q.rational(expr.base), assumptions)
elif ask(Q.rational(expr.exp), assumptions):
if ask(Q.prime(expr.base), assumptions):
return False
def MatPow(expr, assumptions):
# only for integer powers
base, exp = expr.args
int_exp = ask(Q.integer(exp), assumptions)
if not int_exp:
return None
non_negative = ask(~Q.negative(exp), assumptions)
if (non_negative or non_negative == False
and ask(Q.invertible(base), assumptions)):
return ask(Q.complex_elements(base), assumptions)
return None
def Basic(expr, assumptions):
_positive = ask(Q.positive(expr), assumptions)
if _positive:
_integer = ask(Q.integer(expr), assumptions)
if _integer:
_prime = ask(Q.prime(expr), assumptions)
if _prime is None: return
return not _prime
else:
return _integer
else:
return _positive
def _(expr, assumptions):
"""
* Hermitian**Integer -> Hermitian
"""
if expr.is_number:
return None
if expr.base == E:
if ask(Q.hermitian(expr.exp), assumptions):
return True
return
if ask(Q.hermitian(expr.base), assumptions):
if ask(Q.integer(expr.exp), assumptions):
return True
def test_prime():
x, y = symbols('x,y')
assert ask(Q.prime(x), Q.prime(x)) == True
assert ask(Q.prime(x), ~Q.prime(x)) == False
assert ask(Q.prime(x), Q.integer(x)) == None
assert ask(Q.prime(x), ~Q.integer(x)) == False
assert ask(Q.prime(2*x), Q.integer(x)) == False
assert ask(Q.prime(x*y)) == None
assert ask(Q.prime(x*y), Q.prime(x)) == None
assert ask(Q.prime(x*y), Q.integer(x) & Q.integer(y)) == False
assert ask(Q.prime(x**2), Q.integer(x)) == False
assert ask(Q.prime(x**2), Q.prime(x)) == False
assert ask(Q.prime(x**y), Q.integer(x) & Q.integer(y)) == False
def test_prime():
x, y = symbols('x,y')
assert ask(Q.prime(x), Q.prime(x)) == True
assert ask(Q.prime(x), ~Q.prime(x)) == False
assert ask(Q.prime(x), Q.integer(x)) == None
assert ask(Q.prime(x), ~Q.integer(x)) == False
assert ask(Q.prime(2 * x), Q.integer(x)) == False
assert ask(Q.prime(x * y)) == None
assert ask(Q.prime(x * y), Q.prime(x)) == None
assert ask(Q.prime(x * y), Q.integer(x) & Q.integer(y)) == False
assert ask(Q.prime(x**2), Q.integer(x)) == False
assert ask(Q.prime(x**2), Q.prime(x)) == False
assert ask(Q.prime(x**y), Q.integer(x) & Q.integer(y)) == False
def test_composite_proposition():
from sympy.logic.boolalg import Equivalent, Implies
x = symbols('x')
assert ask(True) is True
assert ask(~Q.negative(x), Q.positive(x)) is True
assert ask(~Q.real(x), Q.commutative(x)) is None
assert ask(Q.negative(x) & Q.integer(x), Q.positive(x)) is False
assert ask(Q.negative(x) & Q.integer(x)) is None
assert ask(Q.real(x) | Q.integer(x), Q.positive(x)) is True
assert ask(Q.real(x) | Q.integer(x)) is None
assert ask(Q.real(x) >> Q.positive(x), Q.negative(x)) is False
assert ask(Implies(Q.real(x), Q.positive(x), evaluate=False), Q.negative(x)) is False
assert ask(Implies(Q.real(x), Q.positive(x), evaluate=False)) is None
assert ask(Equivalent(Q.integer(x), Q.even(x)), Q.even(x)) is True
assert ask(Equivalent(Q.integer(x), Q.even(x))) is None
assert ask(Equivalent(Q.positive(x), Q.integer(x)), Q.integer(x)) is None
def test_composite_proposition():
from sympy.logic.boolalg import Equivalent, Implies
x = symbols('x')
assert ask(True) is True
assert ask(~Q.negative(x), Q.positive(x)) is True
assert ask(~Q.real(x), Q.commutative(x)) is None
assert ask(Q.negative(x) & Q.integer(x), Q.positive(x)) is False
assert ask(Q.negative(x) & Q.integer(x)) is None
assert ask(Q.real(x) | Q.integer(x), Q.positive(x)) is True
assert ask(Q.real(x) | Q.integer(x)) is None
assert ask(Q.real(x) >> Q.positive(x), Q.negative(x)) is False
assert ask(Implies(Q.real(x), Q.positive(x), evaluate=False), Q.negative(x)) is False
assert ask(Implies(Q.real(x), Q.positive(x), evaluate=False)) is None
assert ask(Equivalent(Q.integer(x), Q.even(x)), Q.even(x)) is True
assert ask(Equivalent(Q.integer(x), Q.even(x))) is None
assert ask(Equivalent(Q.positive(x), Q.integer(x)), Q.integer(x)) is None
def _(expr, assumptions):
"""
* Hermitian**Integer -> Hermitian
"""
if expr.is_number:
raise MDNotImplementedError
if expr.base == E:
if ask(Q.hermitian(expr.exp), assumptions):
return True
raise MDNotImplementedError
if ask(Q.hermitian(expr.base), assumptions):
if ask(Q.integer(expr.exp), assumptions):
return True
raise MDNotImplementedError
def Pow(expr, assumptions):
"""
Hermitian**Integer -> !Antihermitian
Antihermitian**Even -> !Antihermitian
Antihermitian**Odd -> Antihermitian
"""
if expr.is_number:
return AskImaginaryHandler._number(expr, assumptions)
if ask(Q.hermitian(expr.base), assumptions):
if ask(Q.integer(expr.exp), assumptions):
return False
elif ask(Q.antihermitian(expr.base), assumptions):
if ask(Q.even(expr.exp), assumptions):
return False
elif ask(Q.odd(expr.exp), assumptions):
return True
def _(expr, assumptions):
"""
* Hermitian**Integer -> !Antihermitian
* Antihermitian**Even -> !Antihermitian
* Antihermitian**Odd -> Antihermitian
"""
if expr.is_number:
return None
if ask(Q.hermitian(expr.base), assumptions):
if ask(Q.integer(expr.exp), assumptions):
return False
elif ask(Q.antihermitian(expr.base), assumptions):
if ask(Q.even(expr.exp), assumptions):
return False
elif ask(Q.odd(expr.exp), assumptions):
return True
def _(expr, assumptions):
"""
* Imaginary**Odd -> Imaginary
* Imaginary**Even -> Real
* b**Imaginary -> !Imaginary if exponent is an integer
multiple of I*pi/log(b)
* Imaginary**Real -> ?
* Positive**Real -> Real
* Negative**Integer -> Real
* Negative**(Integer/2) -> Imaginary
* Negative**Real -> not Imaginary if exponent is not Rational
"""
if expr.is_number:
return _Imaginary_number(expr, assumptions)
if expr.base == E:
a = expr.exp / I / pi
return ask(Q.integer(2 * a) & ~Q.integer(a), assumptions)
if expr.base.func == exp or (expr.base.is_Pow and expr.base.base == E):
if ask(Q.imaginary(expr.base.exp), assumptions):
if ask(Q.imaginary(expr.exp), assumptions):
return False
i = expr.base.exp / I / pi
if ask(Q.integer(2 * i), assumptions):
return ask(Q.imaginary((S.NegativeOne**i)**expr.exp),
assumptions)
if ask(Q.imaginary(expr.base), assumptions):
if ask(Q.integer(expr.exp), assumptions):
odd = ask(Q.odd(expr.exp), assumptions)
if odd is not None:
return odd
return
if ask(Q.imaginary(expr.exp), assumptions):
imlog = ask(Q.imaginary(log(expr.base)), assumptions)
if imlog is not None:
# I**i -> real; (2*I)**i -> complex ==> not imaginary
return False
if ask(Q.real(expr.base) & Q.real(expr.exp), assumptions):
if ask(Q.positive(expr.base), assumptions):
return False
else:
rat = ask(Q.rational(expr.exp), assumptions)
if not rat:
return rat
if ask(Q.integer(expr.exp), assumptions):
return False
else:
half = ask(Q.integer(2 * expr.exp), assumptions)
if half:
return ask(Q.negative(expr.base), assumptions)
return half
def test_E():
z = S.Exp1
assert ask(Q.commutative(z)) == True
assert ask(Q.integer(z)) == False
assert ask(Q.rational(z)) == False
assert ask(Q.real(z)) == True
assert ask(Q.complex(z)) == True
assert ask(Q.irrational(z)) == True
assert ask(Q.imaginary(z)) == False
assert ask(Q.positive(z)) == True
assert ask(Q.negative(z)) == False
assert ask(Q.even(z)) == False
assert ask(Q.odd(z)) == False
assert ask(Q.bounded(z)) == True
assert ask(Q.infinitesimal(z)) == False
assert ask(Q.prime(z)) == False
assert ask(Q.composite(z)) == False
def test_zero_0():
z = Integer(0)
assert ask(Q.nonzero(z)) == False
assert ask(Q.commutative(z)) == True
assert ask(Q.integer(z)) == True
assert ask(Q.rational(z)) == True
assert ask(Q.real(z)) == True
assert ask(Q.complex(z)) == True
assert ask(Q.imaginary(z)) == False
assert ask(Q.positive(z)) == False
assert ask(Q.negative(z)) == False
assert ask(Q.even(z)) == True
assert ask(Q.odd(z)) == False
assert ask(Q.bounded(z)) == True
assert ask(Q.infinitesimal(z)) == True
assert ask(Q.prime(z)) == False
assert ask(Q.composite(z)) == False
def _(expr, assumptions):
_positive = ask(Q.positive(expr), assumptions)
if _positive:
_integer = ask(Q.integer(expr), assumptions)
if _integer:
_prime = ask(Q.prime(expr), assumptions)
if _prime is None:
return
# Positive integer which is not prime is not
# necessarily composite
if expr.equals(1):
return False
return not _prime
else:
return _integer
else:
return _positive
def _(expr, assumptions):
"""
* Rational ** Integer -> Rational
* Irrational ** Rational -> Irrational
* Rational ** Irrational -> ?
"""
if expr.base == E:
x = expr.exp
if ask(Q.rational(x), assumptions):
return ask(~Q.nonzero(x), assumptions)
return
if ask(Q.integer(expr.exp), assumptions):
return ask(Q.rational(expr.base), assumptions)
elif ask(Q.rational(expr.exp), assumptions):
if ask(Q.prime(expr.base), assumptions):
return False
def test_Rational_number():
r = Rational(3, 4)
assert ask(Q.commutative(r)) == True
assert ask(Q.integer(r)) == False
assert ask(Q.rational(r)) == True
assert ask(Q.real(r)) == True
assert ask(Q.complex(r)) == True
assert ask(Q.irrational(r)) == False
assert ask(Q.imaginary(r)) == False
assert ask(Q.positive(r)) == True
assert ask(Q.negative(r)) == False
assert ask(Q.even(r)) == False
assert ask(Q.odd(r)) == False
assert ask(Q.bounded(r)) == True
assert ask(Q.infinitesimal(r)) == False
assert ask(Q.prime(r)) == False
assert ask(Q.composite(r)) == False
r = Rational(1, 4)
assert ask(Q.positive(r)) == True
assert ask(Q.negative(r)) == False
r = Rational(5, 4)
assert ask(Q.negative(r)) == False
assert ask(Q.positive(r)) == True
r = Rational(5, 3)
assert ask(Q.positive(r)) == True
assert ask(Q.negative(r)) == False
r = Rational(-3, 4)
assert ask(Q.positive(r)) == False
assert ask(Q.negative(r)) == True
r = Rational(-1, 4)
assert ask(Q.positive(r)) == False
assert ask(Q.negative(r)) == True
r = Rational(-5, 4)
assert ask(Q.negative(r)) == True
assert ask(Q.positive(r)) == False
r = Rational(-5, 3)
assert ask(Q.positive(r)) == False
assert ask(Q.negative(r)) == True
def test_infinity():
oo = S.Infinity
assert ask(Q.commutative(oo)) == True
assert ask(Q.integer(oo)) == False
assert ask(Q.rational(oo)) == False
assert ask(Q.real(oo)) == False
assert ask(Q.extended_real(oo)) == True
assert ask(Q.complex(oo)) == False
assert ask(Q.irrational(oo)) == False
assert ask(Q.imaginary(oo)) == False
assert ask(Q.positive(oo)) == True
assert ask(Q.negative(oo)) == False
assert ask(Q.even(oo)) == False
assert ask(Q.odd(oo)) == False
assert ask(Q.bounded(oo)) == False
assert ask(Q.infinitesimal(oo)) == False
assert ask(Q.prime(oo)) == False
assert ask(Q.composite(oo)) == False
def test_neg_infinity():
mm = S.NegativeInfinity
assert ask(Q.commutative(mm)) == True
assert ask(Q.integer(mm)) == False
assert ask(Q.rational(mm)) == False
assert ask(Q.real(mm)) == False
assert ask(Q.extended_real(mm)) == True
assert ask(Q.complex(mm)) == False
assert ask(Q.irrational(mm)) == False
assert ask(Q.imaginary(mm)) == False
assert ask(Q.positive(mm)) == False
assert ask(Q.negative(mm)) == True
assert ask(Q.even(mm)) == False
assert ask(Q.odd(mm)) == False
assert ask(Q.bounded(mm)) == False
assert ask(Q.infinitesimal(mm)) == False
assert ask(Q.prime(mm)) == False
assert ask(Q.composite(mm)) == False
def test_nan():
nan = S.NaN
assert ask(Q.commutative(nan)) == True
assert ask(Q.integer(nan)) == False
assert ask(Q.rational(nan)) == False
assert ask(Q.real(nan)) == False
assert ask(Q.extended_real(nan)) == False
assert ask(Q.complex(nan)) == False
assert ask(Q.irrational(nan)) == False
assert ask(Q.imaginary(nan)) == False
assert ask(Q.positive(nan)) == False
assert ask(Q.nonzero(nan)) == True
assert ask(Q.even(nan)) == False
assert ask(Q.odd(nan)) == False
assert ask(Q.bounded(nan)) == False
assert ask(Q.infinitesimal(nan)) == False
assert ask(Q.prime(nan)) == False
assert ask(Q.composite(nan)) == False
def _eval_refine(self, assumptions):
from sympy.assumptions import ask, Q
arg = self.args[0]
if arg.is_Mul:
Ioo = S.ImaginaryUnit * S.Infinity
if arg in [Ioo, -Ioo]:
return S.NaN
coeff = arg.as_coefficient(S.Pi * S.ImaginaryUnit)
if coeff:
if ask(Q.integer(2 * coeff)):
if ask(Q.even(coeff)):
return S.One
elif ask(Q.odd(coeff)):
return S.NegativeOne
elif ask(Q.even(coeff + S.Half)):
return -S.ImaginaryUnit
elif ask(Q.odd(coeff + S.Half)):
return S.ImaginaryUnit
def Pow(expr, assumptions):
"""
Real**Integer -> Real
Positive**Real -> Real
Real**(Integer/Even) -> Real if base is nonnegative
Real**(Integer/Odd) -> Real
"""
if expr.is_number:
return AskRealHandler._number(expr, assumptions)
if ask(Q.real(expr.base), assumptions):
if ask(Q.integer(expr.exp), assumptions):
return True
elif expr.exp.is_Rational:
if (expr.exp.q % 2 == 0):
return ask(Q.real(expr.base), assumptions) and \
not ask(Q.negative(expr.base), assumptions)
else: return True
elif ask(Q.real(expr.exp), assumptions):
if ask(Q.positive(expr.base), assumptions):
return True
def test_even():
x, y, z, t = symbols('x,y,z,t')
assert ask(Q.even(x)) == None
assert ask(Q.even(x), Q.integer(x)) == None
assert ask(Q.even(x), ~Q.integer(x)) == False
assert ask(Q.even(x), Q.rational(x)) == None
assert ask(Q.even(x), Q.positive(x)) == None
assert ask(Q.even(2 * x)) == None
assert ask(Q.even(2 * x), Q.integer(x)) == True
assert ask(Q.even(2 * x), Q.even(x)) == True
assert ask(Q.even(2 * x), Q.irrational(x)) == False
assert ask(Q.even(2 * x), Q.odd(x)) == True
assert ask(Q.even(2 * x), ~Q.integer(x)) == None
assert ask(Q.even(3 * x), Q.integer(x)) == None
assert ask(Q.even(3 * x), Q.even(x)) == True
assert ask(Q.even(3 * x), Q.odd(x)) == False
assert ask(Q.even(x + 1), Q.odd(x)) == True
assert ask(Q.even(x + 1), Q.even(x)) == False
assert ask(Q.even(x + 2), Q.odd(x)) == False
assert ask(Q.even(x + 2), Q.even(x)) == True
assert ask(Q.even(7 - x), Q.odd(x)) == True
assert ask(Q.even(7 + x), Q.odd(x)) == True
assert ask(Q.even(x + y), Q.odd(x) & Q.odd(y)) == True
assert ask(Q.even(x + y), Q.odd(x) & Q.even(y)) == False
assert ask(Q.even(x + y), Q.even(x) & Q.even(y)) == True
assert ask(Q.even(2 * x + 1), Q.integer(x)) == False
assert ask(Q.even(2 * x * y), Q.rational(x) & Q.rational(x)) == None
assert ask(Q.even(2 * x * y), Q.irrational(x) & Q.irrational(x)) == None
assert ask(Q.even(x + y + z), Q.odd(x) & Q.odd(y) & Q.even(z)) == True
assert ask(Q.even(x + y + z + t),
Q.odd(x) & Q.odd(y) & Q.even(z) & Q.integer(t)) == None
assert ask(Q.even(Abs(x)), Q.even(x)) == True
assert ask(Q.even(Abs(x)), ~Q.even(x)) == None
assert ask(Q.even(re(x)), Q.even(x)) == True
assert ask(Q.even(re(x)), ~Q.even(x)) == None
assert ask(Q.even(im(x)), Q.even(x)) == True
assert ask(Q.even(im(x)), Q.real(x)) == True
def _(expr, assumptions):
"""
Even * Integer -> Even
Even * Odd -> Even
Integer * Odd -> ?
Odd * Odd -> Odd
Even * Even -> Even
Integer * Integer -> Even if Integer + Integer = Odd
otherwise -> ?
"""
if expr.is_number:
return _EvenPredicate_number(expr, assumptions)
even, odd, irrational, acc = False, 0, False, 1
for arg in expr.args:
# check for all integers and at least one even
if ask(Q.integer(arg), assumptions):
if ask(Q.even(arg), assumptions):
even = True
elif ask(Q.odd(arg), assumptions):
odd += 1
elif not even and acc != 1:
if ask(Q.odd(acc + arg), assumptions):
even = True
elif ask(Q.irrational(arg), assumptions):
# one irrational makes the result False
# two makes it undefined
if irrational:
break
irrational = True
else:
break
acc = arg
else:
if irrational:
return False
if even:
return True
if odd == len(expr.args):
return False
def test_rational():
x, y = symbols('x,y')
assert ask(Q.rational(x), Q.integer(x)) == True
assert ask(Q.rational(x), Q.irrational(x)) == False
assert ask(Q.rational(x), Q.real(x)) == None
assert ask(Q.rational(x), Q.positive(x)) == None
assert ask(Q.rational(x), Q.negative(x)) == None
assert ask(Q.rational(x), Q.nonzero(x)) == None
assert ask(Q.rational(2 * x), Q.rational(x)) == True
assert ask(Q.rational(2 * x), Q.integer(x)) == True
assert ask(Q.rational(2 * x), Q.even(x)) == True
assert ask(Q.rational(2 * x), Q.odd(x)) == True
assert ask(Q.rational(2 * x), Q.irrational(x)) == False
assert ask(Q.rational(x / 2), Q.rational(x)) == True
assert ask(Q.rational(x / 2), Q.integer(x)) == True
assert ask(Q.rational(x / 2), Q.even(x)) == True
assert ask(Q.rational(x / 2), Q.odd(x)) == True
assert ask(Q.rational(x / 2), Q.irrational(x)) == False
assert ask(Q.rational(1 / x), Q.rational(x)) == True
assert ask(Q.rational(1 / x), Q.integer(x)) == True
assert ask(Q.rational(1 / x), Q.even(x)) == True
assert ask(Q.rational(1 / x), Q.odd(x)) == True
assert ask(Q.rational(1 / x), Q.irrational(x)) == False
assert ask(Q.rational(2 / x), Q.rational(x)) == True
assert ask(Q.rational(2 / x), Q.integer(x)) == True
assert ask(Q.rational(2 / x), Q.even(x)) == True
assert ask(Q.rational(2 / x), Q.odd(x)) == True
assert ask(Q.rational(2 / x), Q.irrational(x)) == False
# with multiple symbols
assert ask(Q.rational(x * y), Q.irrational(x) & Q.irrational(y)) == None
assert ask(Q.rational(y / x), Q.rational(x) & Q.rational(y)) == True
assert ask(Q.rational(y / x), Q.integer(x) & Q.rational(y)) == True
assert ask(Q.rational(y / x), Q.even(x) & Q.rational(y)) == True
assert ask(Q.rational(y / x), Q.odd(x) & Q.rational(y)) == True
assert ask(Q.rational(y / x), Q.irrational(x) & Q.rational(y)) == False
def Abs(expr, assumptions):
return ask(Q.integer(expr.args[0]), assumptions)
def refine_Pow(expr, assumptions):
"""
Handler for instances of Pow.
>>> from sympy import Symbol, Q
>>> from sympy.assumptions.refine import refine_Pow
>>> from sympy.abc import x,y,z
>>> refine_Pow((-1)**x, Q.real(x))
>>> refine_Pow((-1)**x, Q.even(x))
1
>>> refine_Pow((-1)**x, Q.odd(x))
-1
For powers of -1, even parts of the exponent can be simplified:
>>> refine_Pow((-1)**(x+y), Q.even(x))
(-1)**y
>>> refine_Pow((-1)**(x+y+z), Q.odd(x) & Q.odd(z))
(-1)**y
>>> refine_Pow((-1)**(x+y+2), Q.odd(x))
(-1)**(y + 1)
>>> refine_Pow((-1)**(x+3), True)
(-1)**(x + 1)
"""
from sympy.core import Pow, Rational
from sympy.functions.elementary.complexes import Abs
from sympy.functions import sign
if isinstance(expr.base, Abs):
if ask(Q.real(expr.base.args[0]), assumptions) and \
ask(Q.even(expr.exp), assumptions):
return expr.base.args[0]**expr.exp
if ask(Q.real(expr.base), assumptions):
if expr.base.is_number:
if ask(Q.even(expr.exp), assumptions):
return abs(expr.base)**expr.exp
if ask(Q.odd(expr.exp), assumptions):
return sign(expr.base) * abs(expr.base)**expr.exp
if isinstance(expr.exp, Rational):
if type(expr.base) is Pow:
return abs(expr.base.base)**(expr.base.exp * expr.exp)
if expr.base is S.NegativeOne:
if expr.exp.is_Add:
old = expr
# For powers of (-1) we can remove
# - even terms
# - pairs of odd terms
# - a single odd term + 1
# - A numerical constant N can be replaced with mod(N,2)
coeff, terms = expr.exp.as_coeff_add()
terms = set(terms)
even_terms = set([])
odd_terms = set([])
initial_number_of_terms = len(terms)
for t in terms:
if ask(Q.even(t), assumptions):
even_terms.add(t)
elif ask(Q.odd(t), assumptions):
odd_terms.add(t)
terms -= even_terms
if len(odd_terms) % 2:
terms -= odd_terms
new_coeff = (coeff + S.One) % 2
else:
terms -= odd_terms
new_coeff = coeff % 2
if new_coeff != coeff or len(terms) < initial_number_of_terms:
terms.add(new_coeff)
expr = expr.base**(Add(*terms))
# Handle (-1)**((-1)**n/2 + m/2)
e2 = 2 * expr.exp
if ask(Q.even(e2), assumptions):
if e2.could_extract_minus_sign():
e2 *= expr.base
if e2.is_Add:
i, p = e2.as_two_terms()
if p.is_Pow and p.base is S.NegativeOne:
if ask(Q.integer(p.exp), assumptions):
i = (i + 1) / 2
if ask(Q.even(i), assumptions):
return expr.base**p.exp
elif ask(Q.odd(i), assumptions):
return expr.base**(p.exp + 1)
else:
return expr.base**(p.exp + i)
if old != expr:
return expr
def _(expr, assumptions):
a = expr.exp / I / pi
return ask(Q.integer(2 * a) & ~Q.integer(a), assumptions)
def _(expr, assumptions):
return ask(Q.integer(expr.exp / I / pi) | Q.real(expr.exp), assumptions)
def _(expr, assumptions):
"""
* Real**Integer -> Real
* Positive**Real -> Real
* Real**(Integer/Even) -> Real if base is nonnegative
* Real**(Integer/Odd) -> Real
* Imaginary**(Integer/Even) -> Real
* Imaginary**(Integer/Odd) -> not Real
* Imaginary**Real -> ? since Real could be 0 (giving real)
or 1 (giving imaginary)
* b**Imaginary -> Real if log(b) is imaginary and b != 0
and exponent != integer multiple of
I*pi/log(b)
* Real**Real -> ? e.g. sqrt(-1) is imaginary and
sqrt(2) is not
"""
if expr.is_number:
return _RealPredicate_number(expr, assumptions)
if expr.base == E:
return ask(
Q.integer(expr.exp / I / pi) | Q.real(expr.exp), assumptions)
if expr.base.func == exp or (expr.base.is_Pow and expr.base.base == E):
if ask(Q.imaginary(expr.base.exp), assumptions):
if ask(Q.imaginary(expr.exp), assumptions):
return True
# If the i = (exp's arg)/(I*pi) is an integer or half-integer
# multiple of I*pi then 2*i will be an integer. In addition,
# exp(i*I*pi) = (-1)**i so the overall realness of the expr
# can be determined by replacing exp(i*I*pi) with (-1)**i.
i = expr.base.exp / I / pi
if ask(Q.integer(2 * i), assumptions):
return ask(Q.real(((-1)**i)**expr.exp), assumptions)
return
if ask(Q.imaginary(expr.base), assumptions):
if ask(Q.integer(expr.exp), assumptions):
odd = ask(Q.odd(expr.exp), assumptions)
if odd is not None:
return not odd
return
if ask(Q.imaginary(expr.exp), assumptions):
imlog = ask(Q.imaginary(log(expr.base)), assumptions)
if imlog is not None:
# I**i -> real, log(I) is imag;
# (2*I)**i -> complex, log(2*I) is not imag
return imlog
if ask(Q.real(expr.base), assumptions):
if ask(Q.real(expr.exp), assumptions):
if expr.exp.is_Rational and \
ask(Q.even(expr.exp.q), assumptions):
return ask(Q.positive(expr.base), assumptions)
elif ask(Q.integer(expr.exp), assumptions):
return True
elif ask(Q.positive(expr.base), assumptions):
return True
elif ask(Q.negative(expr.base), assumptions):
return False
