def refine_abs(expr, assumptions):
"""
Handler for the absolute value.
Examples::
>>> from sympy import Symbol, Assume, Q, refine
>>> from sympy.assumptions.refine import refine_abs
>>> from sympy.abc import x
>>> refine_abs(abs(x), Assume(x, Q.real))
>>> refine_abs(abs(x), Assume(x, Q.positive))
x
>>> refine_abs(abs(x), Assume(x, Q.negative))
-x
"""
arg = expr.args[0]
if ask(arg, Q.real, assumptions) and fuzzy_not(ask(arg, Q.negative, assumptions)):
# if it's nonnegative
return arg
if ask(arg, Q.negative, assumptions):
return -arg
def refine_abs(expr, assumptions):
"""
Handler for the absolute value.
Examples::
>>> from sympy import Symbol, Assume, Q, refine, Abs
>>> from sympy.assumptions.refine import refine_abs
>>> from sympy.abc import x
>>> refine_abs(Abs(x), Assume(x, Q.real))
>>> refine_abs(Abs(x), Assume(x, Q.positive))
x
>>> refine_abs(Abs(x), Assume(x, Q.negative))
-x
"""
arg = expr.args[0]
if ask(arg, Q.real, assumptions) and \
fuzzy_not(ask(arg, Q.negative, assumptions)):
# if it's nonnegative
return arg
if ask(arg, Q.negative, assumptions):
return -arg
def refine_abs(expr, assumptions):
"""
Handler for the absolute value.
Examples
========
>>> from sympy import Symbol, Q, refine, Abs
>>> from sympy.assumptions.refine import refine_abs
>>> from sympy.abc import x
>>> refine_abs(Abs(x), Q.real(x))
>>> refine_abs(Abs(x), Q.positive(x))
x
>>> refine_abs(Abs(x), Q.negative(x))
-x
"""
arg = expr.args[0]
if ask(Q.real(arg), assumptions) and \
fuzzy_not(ask(Q.negative(arg), assumptions)):
# if it's nonnegative
return arg
if ask(Q.negative(arg), assumptions):
return -arg
def test_fuzzy_not():
assert fuzzy_not(False) == True
assert fuzzy_not(True) == False
assert fuzzy_not(None) == None
def test_fuzzy_not():
assert fuzzy_not(False) == True
assert fuzzy_not(True) == False
assert fuzzy_not(None) == None
