def eval(cls, arg):
from sympy.simplify.simplify import signsimp
if hasattr(arg, '_eval_Abs'):
obj = arg._eval_Abs()
if obj is not None:
return obj
# handle what we can
arg = signsimp(arg, evaluate=False)
if arg.is_Mul:
known = []
unk = []
for t in arg.args:
tnew = cls(t)
if tnew.func is cls:
unk.append(tnew.args[0])
else:
known.append(tnew)
known = Mul(*known)
unk = cls(Mul(*unk), evaluate=False) if unk else S.One
return known*unk
if arg is S.NaN:
return S.NaN
if arg.is_Pow:
base, exponent = arg.as_base_exp()
if base.is_real:
if exponent.is_integer:
if exponent.is_even:
return arg
if base is S.NegativeOne:
return S.One
if base.func is cls and exponent is S.NegativeOne:
return arg
return Abs(base)**exponent
if base.is_positive == True:
return base**re(exponent)
return (-base)**re(exponent)*C.exp(-S.Pi*im(exponent))
if isinstance(arg, C.exp):
return C.exp(re(arg.args[0]))
if arg.is_zero: # it may be an Expr that is zero
return S.Zero
if arg.is_nonnegative:
return arg
if arg.is_nonpositive:
return -arg
if arg.is_imaginary:
arg2 = -S.ImaginaryUnit * arg
if arg2.is_nonnegative:
return arg2
if arg.is_Add:
if arg.has(S.Infinity, S.NegativeInfinity):
if any(a.is_infinite for a in arg.as_real_imag()):
return S.Infinity
if arg.is_real is None and arg.is_imaginary is None:
if all(a.is_real or a.is_imaginary or (S.ImaginaryUnit*a).is_real for a in arg.args):
from sympy import expand_mul
return sqrt(expand_mul(arg*arg.conjugate()))
if arg.is_real is False and arg.is_imaginary is False:
from sympy import expand_mul
return sqrt(expand_mul(arg*arg.conjugate()))
def eval(cls, arg):
from sympy.simplify.simplify import signsimp
from sympy.core.function import expand_mul
if hasattr(arg, '_eval_Abs'):
obj = arg._eval_Abs()
if obj is not None:
return obj
# handle what we can
arg = signsimp(arg, evaluate=False)
if arg is S.NaN:
return S.NaN
if arg is S.ComplexInfinity:
return S.Infinity
if isinstance(arg, exp):
return exp(re(arg.args[0]))
if isinstance(arg, AppliedUndef) or arg.is_set:
return
if arg.is_Add and arg.has(S.Infinity, S.NegativeInfinity):
if any(a.is_infinite for a in arg.as_real_imag()):
return S.Infinity
if arg.is_zero:
return S.Zero
if arg.is_extended_nonnegative:
return arg
if arg.is_extended_nonpositive:
return -arg
if arg.is_imaginary:
arg2 = -S.ImaginaryUnit * arg
if arg2.is_extended_nonnegative:
return arg2
# reject result if all new conjugates are just wrappers around
# an expression that was already in the arg
conj = signsimp(arg.conjugate(), evaluate=False)
new_conj = conj.atoms(conjugate) - arg.atoms(conjugate)
if new_conj and all(arg.has(i.args[0]) for i in new_conj):
return
if arg != conj and arg != -conj:
ignore = arg.atoms(Abs)
abs_free_arg = arg.xreplace({i: Dummy(real=True) for i in ignore})
unk = [a for a in abs_free_arg.free_symbols if a.is_extended_real is None]
if not unk or not all(conj.has(conjugate(u)) for u in unk):
return sqrt(expand_mul(arg * conj))
def _combine_inverse(lhs, rhs):
"""
Returns lhs - rhs, but treats oo like a symbol so oo - oo
returns 0, instead of a nan.
"""
from sympy.simplify.simplify import signsimp
from sympy.core.symbol import Dummy
inf = (S.Infinity, S.NegativeInfinity)
if lhs.has(*inf) or rhs.has(*inf):
oo = Dummy('oo')
reps = {S.Infinity: oo, S.NegativeInfinity: -oo}
ireps = {v: k for k, v in reps.items()}
eq = signsimp(lhs.xreplace(reps) - rhs.xreplace(reps))
if eq.has(oo):
eq = eq.replace(lambda x: x.is_Pow and x.base is oo,
lambda x: x.base)
return eq.xreplace(ireps)
else:
return signsimp(lhs - rhs)
def test_match_issue_21942():
a, r, w = symbols('a, r, w', nonnegative=True)
p = symbols('p', positive=True)
g_ = Wild('g')
pattern = g_ ** (1 / (1 - p))
eq = (a * r ** (1 - p) + w ** (1 - p) * (1 - a)) ** (1 / (1 - p))
m = {g_: a * r ** (1 - p) + w ** (1 - p) * (1 - a)}
assert pattern.matches(eq) == m
assert (-pattern).matches(-eq) == m
assert pattern.matches(signsimp(eq)) is None
def f(rv):
if not isinstance(rv, TrigonometricFunction):
return rv
rv = rv.func(signsimp(rv.args[0]))
if not isinstance(rv, TrigonometricFunction):
return rv
if (rv.args[0] - S.Pi / 4).is_positive is (
S.Pi / 2 - rv.args[0]).is_positive is True:
fmap = {cos: sin, sin: cos, tan: cot, cot: tan, sec: csc, csc: sec}
rv = fmap[rv.func](S.Pi / 2 - rv.args[0])
return rv
def eval(cls, arg):
from sympy.simplify.simplify import signsimp
if hasattr(arg, "_eval_Abs"):
obj = arg._eval_Abs()
if obj is not None:
return obj
# handle what we can
arg = signsimp(arg, evaluate=False)
if arg.is_Mul:
known = []
unk = []
for t in arg.args:
tnew = cls(t)
if tnew.func is cls:
unk.append(tnew.args[0])
else:
known.append(tnew)
known = Mul(*known)
unk = cls(Mul(*unk), evaluate=False) if unk else S.One
return known * unk
if arg is S.NaN:
return S.NaN
if arg.is_zero: # it may be an Expr that is zero
return S.Zero
if arg.is_nonnegative:
return arg
if arg.is_nonpositive:
return -arg
if arg.is_imaginary:
arg2 = -S.ImaginaryUnit * arg
if arg2.is_nonnegative:
return arg2
if arg.is_real is False and arg.is_imaginary is False:
from sympy import expand_mul
return sqrt(expand_mul(arg * arg.conjugate()))
if arg.is_real is None and arg.is_imaginary is None and arg.is_Add:
if all(a.is_real or a.is_imaginary or (S.ImaginaryUnit * a).is_real for a in arg.args):
from sympy import expand_mul
return sqrt(expand_mul(arg * arg.conjugate()))
if arg.is_Pow:
base, exponent = arg.as_base_exp()
if exponent.is_even and base.is_real:
return arg
if exponent.is_integer and base is S.NegativeOne:
return S.One
def hyper_as_trig(rv):
from sympy.simplify.simplify import signsimp
from sympy.simplify.radsimp import collect
# mask off trig functions
trigs = rv.atoms(TrigonometricFunction)
reps = [(t, Dummy()) for t in trigs]
masked = rv.xreplace(dict(reps))
# get inversion substitutions in place
reps = [(v, k) for k, v in reps]
d = Dummy()
return _osborne(masked, d), lambda x: collect(
signsimp(_osbornei(x, d).xreplace(dict(reps))), S.ImaginaryUnit)
def eval(cls, arg):
from sympy.simplify.simplify import signsimp
if hasattr(arg, '_eval_Abs'):
obj = arg._eval_Abs()
if obj is not None:
return obj
# handle what we can
arg = signsimp(arg, evaluate=False)
if arg.is_Mul:
known = []
unk = []
for t in arg.args:
tnew = cls(t)
if tnew.func is cls:
unk.append(tnew.args[0])
else:
known.append(tnew)
known = Mul(*known)
unk = cls(Mul(*unk), evaluate=False) if unk else S.One
return known * unk
if arg is S.NaN:
return S.NaN
if arg.is_zero: # it may be an Expr that is zero
return S.Zero
if arg.is_nonnegative:
return arg
if arg.is_nonpositive:
return -arg
if arg.is_imaginary:
arg2 = -S.ImaginaryUnit * arg
if arg2.is_nonnegative:
return arg2
if arg.is_real is False and arg.is_imaginary is False:
from sympy import expand_mul
return sqrt(expand_mul(arg * arg.conjugate()))
if arg.is_real is None and arg.is_imaginary is None and arg.is_Add:
if all(a.is_real or a.is_imaginary or (S.ImaginaryUnit * a).is_real
for a in arg.args):
from sympy import expand_mul
return sqrt(expand_mul(arg * arg.conjugate()))
if arg.is_Pow:
base, exponent = arg.as_base_exp()
if exponent.is_even and base.is_real:
return arg
if exponent.is_integer and base is S.NegativeOne:
return S.One
def test_issue_17524():
a = symbols("a", real=True)
e = (-1 - a**2)*sqrt(1 + a**2)
assert signsimp(powsimp(e)) == signsimp(e) == -(a**2 + 1)**(S(3)/2)
def eval(cls, arg):
from sympy.simplify.simplify import signsimp
from sympy.core.function import expand_mul
if hasattr(arg, '_eval_Abs'):
obj = arg._eval_Abs()
if obj is not None:
return obj
if not isinstance(arg, Expr):
raise TypeError("Bad argument type for Abs(): %s" % type(arg))
# handle what we can
arg = signsimp(arg, evaluate=False)
if arg.is_Mul:
known = []
unk = []
for t in arg.args:
tnew = cls(t)
if isinstance(tnew, cls):
unk.append(tnew.args[0])
else:
known.append(tnew)
known = Mul(*known)
unk = cls(Mul(*unk), evaluate=False) if unk else S.One
return known*unk
if arg is S.NaN:
return S.NaN
if arg is S.ComplexInfinity:
return S.Infinity
if arg.is_Pow:
base, exponent = arg.as_base_exp()
if base.is_real:
if exponent.is_integer:
if exponent.is_even:
return arg
if base is S.NegativeOne:
return S.One
if isinstance(base, cls) and exponent is S.NegativeOne:
return arg
return Abs(base)**exponent
if base.is_nonnegative:
return base**re(exponent)
if base.is_negative:
return (-base)**re(exponent)*exp(-S.Pi*im(exponent))
return
elif not base.has(Symbol): # complex base
# express base**exponent as exp(exponent*log(base))
a, b = log(base).as_real_imag()
z = a + I*b
return exp(re(exponent*z))
if isinstance(arg, exp):
return exp(re(arg.args[0]))
if isinstance(arg, AppliedUndef):
return
if arg.is_Add and arg.has(S.Infinity, S.NegativeInfinity):
if any(a.is_infinite for a in arg.as_real_imag()):
return S.Infinity
if arg.is_zero:
return S.Zero
if arg.is_nonnegative:
return arg
if arg.is_nonpositive:
return -arg
if arg.is_imaginary:
arg2 = -S.ImaginaryUnit * arg
if arg2.is_nonnegative:
return arg2
# reject result if all new conjugates are just wrappers around
# an expression that was already in the arg
conj = signsimp(arg.conjugate(), evaluate=False)
new_conj = conj.atoms(conjugate) - arg.atoms(conjugate)
if new_conj and all(arg.has(i.args[0]) for i in new_conj):
return
if arg != conj and arg != -conj:
ignore = arg.atoms(Abs)
abs_free_arg = arg.xreplace({i: Dummy(real=True) for i in ignore})
unk = [a for a in abs_free_arg.free_symbols if a.is_real is None]
if not unk or not all(conj.has(conjugate(u)) for u in unk):
return sqrt(expand_mul(arg*conj))
def eval(cls, arg):
from sympy.simplify.simplify import signsimp
from sympy.core.function import expand_mul
from sympy.core.power import Pow
if hasattr(arg, '_eval_Abs'):
obj = arg._eval_Abs()
if obj is not None:
return obj
if not isinstance(arg, Expr):
raise TypeError("Bad argument type for Abs(): %s" % type(arg))
# handle what we can
arg = signsimp(arg, evaluate=False)
n, d = arg.as_numer_denom()
if d.free_symbols and not n.free_symbols:
return cls(n) / cls(d)
if arg.is_Mul:
known = []
unk = []
for t in arg.args:
if t.is_Pow and t.exp.is_integer and t.exp.is_negative:
bnew = cls(t.base)
if isinstance(bnew, cls):
unk.append(t)
else:
known.append(Pow(bnew, t.exp))
else:
tnew = cls(t)
if isinstance(tnew, cls):
unk.append(t)
else:
known.append(tnew)
known = Mul(*known)
unk = cls(Mul(*unk), evaluate=False) if unk else S.One
return known * unk
if arg is S.NaN:
return S.NaN
if arg is S.ComplexInfinity:
return S.Infinity
if arg.is_Pow:
base, exponent = arg.as_base_exp()
if base.is_extended_real:
if exponent.is_integer:
if exponent.is_even:
return arg
if base is S.NegativeOne:
return S.One
return Abs(base)**exponent
if base.is_extended_nonnegative:
return base**re(exponent)
if base.is_extended_negative:
return (-base)**re(exponent) * exp(-S.Pi * im(exponent))
return
elif not base.has(Symbol): # complex base
# express base**exponent as exp(exponent*log(base))
a, b = log(base).as_real_imag()
z = a + I * b
return exp(re(exponent * z))
if isinstance(arg, exp):
return exp(re(arg.args[0]))
if isinstance(arg, AppliedUndef):
return
if arg.is_Add and arg.has(S.Infinity, S.NegativeInfinity):
if any(a.is_infinite for a in arg.as_real_imag()):
return S.Infinity
if arg.is_zero:
return S.Zero
if arg.is_extended_nonnegative:
return arg
if arg.is_extended_nonpositive:
return -arg
if arg.is_imaginary:
arg2 = -S.ImaginaryUnit * arg
if arg2.is_extended_nonnegative:
return arg2
# reject result if all new conjugates are just wrappers around
# an expression that was already in the arg
conj = signsimp(arg.conjugate(), evaluate=False)
new_conj = conj.atoms(conjugate) - arg.atoms(conjugate)
if new_conj and all(arg.has(i.args[0]) for i in new_conj):
return
if arg != conj and arg != -conj:
ignore = arg.atoms(Abs)
abs_free_arg = arg.xreplace({i: Dummy(real=True) for i in ignore})
unk = [
a for a in abs_free_arg.free_symbols
if a.is_extended_real is None
]
if not unk or not all(conj.has(conjugate(u)) for u in unk):
return sqrt(expand_mul(arg * conj))
def radsimp(expr, symbolic=True, max_terms=4):
r"""
Rationalize the denominator by removing square roots.
Note: the expression returned from radsimp must be used with caution
since if the denominator contains symbols, it will be possible to make
substitutions that violate the assumptions of the simplification process:
that for a denominator matching a + b*sqrt(c), a != +/-b*sqrt(c). (If
there are no symbols, this assumptions is made valid by collecting terms
of sqrt(c) so the match variable ``a`` does not contain ``sqrt(c)``.) If
you do not want the simplification to occur for symbolic denominators, set
``symbolic`` to False.
If there are more than ``max_terms`` radical terms then the expression is
returned unchanged.
Examples
========
>>> from sympy import radsimp, sqrt, Symbol, denom, pprint, I
>>> from sympy import factor_terms, fraction, signsimp
>>> from sympy.simplify.radsimp import collect_sqrt
>>> from sympy.abc import a, b, c
>>> radsimp(1/(2 + sqrt(2)))
(-sqrt(2) + 2)/2
>>> x,y = map(Symbol, 'xy')
>>> e = ((2 + 2*sqrt(2))*x + (2 + sqrt(8))*y)/(2 + sqrt(2))
>>> radsimp(e)
sqrt(2)*(x + y)
No simplification beyond removal of the gcd is done. One might
want to polish the result a little, however, by collecting
square root terms:
>>> r2 = sqrt(2)
>>> r5 = sqrt(5)
>>> ans = radsimp(1/(y*r2 + x*r2 + a*r5 + b*r5)); pprint(ans)
___ ___ ___ ___
\/ 5 *a + \/ 5 *b - \/ 2 *x - \/ 2 *y
------------------------------------------
2 2 2 2
5*a + 10*a*b + 5*b - 2*x - 4*x*y - 2*y
>>> n, d = fraction(ans)
>>> pprint(factor_terms(signsimp(collect_sqrt(n))/d, radical=True))
___ ___
\/ 5 *(a + b) - \/ 2 *(x + y)
------------------------------------------
2 2 2 2
5*a + 10*a*b + 5*b - 2*x - 4*x*y - 2*y
If radicals in the denominator cannot be removed or there is no denominator,
the original expression will be returned.
>>> radsimp(sqrt(2)*x + sqrt(2))
sqrt(2)*x + sqrt(2)
Results with symbols will not always be valid for all substitutions:
>>> eq = 1/(a + b*sqrt(c))
>>> eq.subs(a, b*sqrt(c))
1/(2*b*sqrt(c))
>>> radsimp(eq).subs(a, b*sqrt(c))
nan
If symbolic=False, symbolic denominators will not be transformed (but
numeric denominators will still be processed):
>>> radsimp(eq, symbolic=False)
1/(a + b*sqrt(c))
"""
from sympy.simplify.simplify import signsimp
syms = symbols("a:d A:D")
def _num(rterms):
# return the multiplier that will simplify the expression described
# by rterms [(sqrt arg, coeff), ... ]
a, b, c, d, A, B, C, D = syms
if len(rterms) == 2:
reps = dict(list(zip([A, a, B, b], [j for i in rterms for j in i])))
return (
sqrt(A)*a - sqrt(B)*b).xreplace(reps)
if len(rterms) == 3:
reps = dict(list(zip([A, a, B, b, C, c], [j for i in rterms for j in i])))
return (
(sqrt(A)*a + sqrt(B)*b - sqrt(C)*c)*(2*sqrt(A)*sqrt(B)*a*b - A*a**2 -
B*b**2 + C*c**2)).xreplace(reps)
elif len(rterms) == 4:
reps = dict(list(zip([A, a, B, b, C, c, D, d], [j for i in rterms for j in i])))
return ((sqrt(A)*a + sqrt(B)*b - sqrt(C)*c - sqrt(D)*d)*(2*sqrt(A)*sqrt(B)*a*b
- A*a**2 - B*b**2 - 2*sqrt(C)*sqrt(D)*c*d + C*c**2 +
D*d**2)*(-8*sqrt(A)*sqrt(B)*sqrt(C)*sqrt(D)*a*b*c*d + A**2*a**4 -
2*A*B*a**2*b**2 - 2*A*C*a**2*c**2 - 2*A*D*a**2*d**2 + B**2*b**4 -
2*B*C*b**2*c**2 - 2*B*D*b**2*d**2 + C**2*c**4 - 2*C*D*c**2*d**2 +
D**2*d**4)).xreplace(reps)
elif len(rterms) == 1:
return sqrt(rterms[0][0])
else:
raise NotImplementedError
def ispow2(d, log2=False):
if not d.is_Pow:
return False
e = d.exp
if e.is_Rational and e.q == 2 or symbolic and denom(e) == 2:
return True
if log2:
q = 1
if e.is_Rational:
q = e.q
elif symbolic:
d = denom(e)
if d.is_Integer:
q = d
if q != 1 and log(q, 2).is_Integer:
return True
return False
def handle(expr):
# Handle first reduces to the case
# expr = 1/d, where d is an add, or d is base**p/2.
# We do this by recursively calling handle on each piece.
from sympy.simplify.simplify import nsimplify
n, d = fraction(expr)
if expr.is_Atom or (d.is_Atom and n.is_Atom):
return expr
elif not n.is_Atom:
n = n.func(*[handle(a) for a in n.args])
return _unevaluated_Mul(n, handle(1/d))
elif n is not S.One:
return _unevaluated_Mul(n, handle(1/d))
elif d.is_Mul:
return _unevaluated_Mul(*[handle(1/d) for d in d.args])
# By this step, expr is 1/d, and d is not a mul.
if not symbolic and d.free_symbols:
return expr
if ispow2(d):
d2 = sqrtdenest(sqrt(d.base))**numer(d.exp)
if d2 != d:
return handle(1/d2)
elif d.is_Pow and (d.exp.is_integer or d.base.is_positive):
# (1/d**i) = (1/d)**i
return handle(1/d.base)**d.exp
if not (d.is_Add or ispow2(d)):
return 1/d.func(*[handle(a) for a in d.args])
# handle 1/d treating d as an Add (though it may not be)
keep = True # keep changes that are made
# flatten it and collect radicals after checking for special
# conditions
d = _mexpand(d)
# did it change?
if d.is_Atom:
return 1/d
# is it a number that might be handled easily?
if d.is_number:
_d = nsimplify(d)
if _d.is_Number and _d.equals(d):
return 1/_d
while True:
# collect similar terms
collected = defaultdict(list)
for m in Add.make_args(d): # d might have become non-Add
p2 = []
other = []
for i in Mul.make_args(m):
if ispow2(i, log2=True):
p2.append(i.base if i.exp is S.Half else i.base**(2*i.exp))
elif i is S.ImaginaryUnit:
p2.append(S.NegativeOne)
else:
other.append(i)
collected[tuple(ordered(p2))].append(Mul(*other))
rterms = list(ordered(list(collected.items())))
rterms = [(Mul(*i), Add(*j)) for i, j in rterms]
nrad = len(rterms) - (1 if rterms[0][0] is S.One else 0)
if nrad < 1:
break
elif nrad > max_terms:
# there may have been invalid operations leading to this point
# so don't keep changes, e.g. this expression is troublesome
# in collecting terms so as not to raise the issue of 2834:
# r = sqrt(sqrt(5) + 5)
# eq = 1/(sqrt(5)*r + 2*sqrt(5)*sqrt(-sqrt(5) + 5) + 5*r)
keep = False
break
if len(rterms) > 4:
# in general, only 4 terms can be removed with repeated squaring
# but other considerations can guide selection of radical terms
# so that radicals are removed
if all([x.is_Integer and (y**2).is_Rational for x, y in rterms]):
nd, d = rad_rationalize(S.One, Add._from_args(
[sqrt(x)*y for x, y in rterms]))
n *= nd
else:
# is there anything else that might be attempted?
keep = False
break
from sympy.simplify.powsimp import powsimp, powdenest
num = powsimp(_num(rterms))
n *= num
d *= num
d = powdenest(_mexpand(d), force=symbolic)
if d.is_Atom:
break
if not keep:
return expr
return _unevaluated_Mul(n, 1/d)
coeff, expr = expr.as_coeff_Add()
expr = expr.normal()
old = fraction(expr)
n, d = fraction(handle(expr))
if old != (n, d):
if not d.is_Atom:
was = (n, d)
n = signsimp(n, evaluate=False)
d = signsimp(d, evaluate=False)
u = Factors(_unevaluated_Mul(n, 1/d))
u = _unevaluated_Mul(*[k**v for k, v in u.factors.items()])
n, d = fraction(u)
if old == (n, d):
n, d = was
n = expand_mul(n)
if d.is_Number or d.is_Add:
n2, d2 = fraction(gcd_terms(_unevaluated_Mul(n, 1/d)))
if d2.is_Number or (d2.count_ops() <= d.count_ops()):
n, d = [signsimp(i) for i in (n2, d2)]
if n.is_Mul and n.args[0].is_Number:
n = n.func(*n.args)
return coeff + _unevaluated_Mul(n, 1/d)
def _solveset(f, symbol, domain, _check=False):
"""Helper for solveset to return a result from an expression
that has already been sympify'ed and is known to contain the
given symbol."""
# _check controls whether the answer is checked or not
from sympy.simplify.simplify import signsimp
orig_f = f
f = together(f)
if f.is_Mul:
_, f = f.as_independent(symbol, as_Add=False)
if f.is_Add:
a, h = f.as_independent(symbol)
m, h = h.as_independent(symbol, as_Add=False)
f = a/m + h # XXX condition `m != 0` should be added to soln
f = piecewise_fold(f)
# assign the solvers to use
solver = lambda f, x, domain=domain: _solveset(f, x, domain)
if domain.is_subset(S.Reals):
inverter_func = invert_real
else:
inverter_func = invert_complex
inverter = lambda f, rhs, symbol: inverter_func(f, rhs, symbol, domain)
result = EmptySet()
if f.expand().is_zero:
return domain
elif not f.has(symbol):
return EmptySet()
elif f.is_Mul and all(_is_finite_with_finite_vars(m, domain)
for m in f.args):
# if f(x) and g(x) are both finite we can say that the solution of
# f(x)*g(x) == 0 is same as Union(f(x) == 0, g(x) == 0) is not true in
# general. g(x) can grow to infinitely large for the values where
# f(x) == 0. To be sure that we are not silently allowing any
# wrong solutions we are using this technique only if both f and g are
# finite for a finite input.
result = Union(*[solver(m, symbol) for m in f.args])
elif _is_function_class_equation(TrigonometricFunction, f, symbol) or \
_is_function_class_equation(HyperbolicFunction, f, symbol):
result = _solve_trig(f, symbol, domain)
elif f.is_Piecewise:
dom = domain
result = EmptySet()
expr_set_pairs = f.as_expr_set_pairs()
for (expr, in_set) in expr_set_pairs:
if in_set.is_Relational:
in_set = in_set.as_set()
if in_set.is_Interval:
dom -= in_set
solns = solver(expr, symbol, in_set)
result += solns
else:
lhs, rhs_s = inverter(f, 0, symbol)
if lhs == symbol:
# do some very minimal simplification since
# repeated inversion may have left the result
# in a state that other solvers (e.g. poly)
# would have simplified; this is done here
# rather than in the inverter since here it
# is only done once whereas there it would
# be repeated for each step of the inversion
if isinstance(rhs_s, FiniteSet):
rhs_s = FiniteSet(*[Mul(*
signsimp(i).as_content_primitive())
for i in rhs_s])
result = rhs_s
elif isinstance(rhs_s, FiniteSet):
for equation in [lhs - rhs for rhs in rhs_s]:
if equation == f:
if any(_has_rational_power(g, symbol)[0]
for g in equation.args) or _has_rational_power(
equation, symbol)[0]:
result += _solve_radical(equation,
symbol,
solver)
elif equation.has(Abs):
result += _solve_abs(f, symbol, domain)
else:
result += _solve_as_rational(equation, symbol, domain)
else:
result += solver(equation, symbol)
else:
result = ConditionSet(symbol, Eq(f, 0), domain)
if _check:
if isinstance(result, ConditionSet):
# it wasn't solved or has enumerated all conditions
# -- leave it alone
return result
# whittle away all but the symbol-containing core
# to use this for testing
fx = orig_f.as_independent(symbol, as_Add=True)[1]
fx = fx.as_independent(symbol, as_Add=False)[1]
if isinstance(result, FiniteSet):
# check the result for invalid solutions
result = FiniteSet(*[s for s in result
if isinstance(s, RootOf)
or domain_check(fx, symbol, s)])
return result
def radsimp(expr, symbolic=True, max_terms=4):
r"""
Rationalize the denominator by removing square roots.
Explanation
===========
The expression returned from radsimp must be used with caution
since if the denominator contains symbols, it will be possible to make
substitutions that violate the assumptions of the simplification process:
that for a denominator matching a + b*sqrt(c), a != +/-b*sqrt(c). (If
there are no symbols, this assumptions is made valid by collecting terms
of sqrt(c) so the match variable ``a`` does not contain ``sqrt(c)``.) If
you do not want the simplification to occur for symbolic denominators, set
``symbolic`` to False.
If there are more than ``max_terms`` radical terms then the expression is
returned unchanged.
Examples
========
>>> from sympy import radsimp, sqrt, Symbol, pprint
>>> from sympy import factor_terms, fraction, signsimp
>>> from sympy.simplify.radsimp import collect_sqrt
>>> from sympy.abc import a, b, c
>>> radsimp(1/(2 + sqrt(2)))
(2 - sqrt(2))/2
>>> x,y = map(Symbol, 'xy')
>>> e = ((2 + 2*sqrt(2))*x + (2 + sqrt(8))*y)/(2 + sqrt(2))
>>> radsimp(e)
sqrt(2)*(x + y)
No simplification beyond removal of the gcd is done. One might
want to polish the result a little, however, by collecting
square root terms:
>>> r2 = sqrt(2)
>>> r5 = sqrt(5)
>>> ans = radsimp(1/(y*r2 + x*r2 + a*r5 + b*r5)); pprint(ans)
___ ___ ___ ___
\/ 5 *a + \/ 5 *b - \/ 2 *x - \/ 2 *y
------------------------------------------
2 2 2 2
5*a + 10*a*b + 5*b - 2*x - 4*x*y - 2*y
>>> n, d = fraction(ans)
>>> pprint(factor_terms(signsimp(collect_sqrt(n))/d, radical=True))
___ ___
\/ 5 *(a + b) - \/ 2 *(x + y)
------------------------------------------
2 2 2 2
5*a + 10*a*b + 5*b - 2*x - 4*x*y - 2*y
If radicals in the denominator cannot be removed or there is no denominator,
the original expression will be returned.
>>> radsimp(sqrt(2)*x + sqrt(2))
sqrt(2)*x + sqrt(2)
Results with symbols will not always be valid for all substitutions:
>>> eq = 1/(a + b*sqrt(c))
>>> eq.subs(a, b*sqrt(c))
1/(2*b*sqrt(c))
>>> radsimp(eq).subs(a, b*sqrt(c))
nan
If ``symbolic=False``, symbolic denominators will not be transformed (but
numeric denominators will still be processed):
>>> radsimp(eq, symbolic=False)
1/(a + b*sqrt(c))
"""
from sympy.simplify.simplify import signsimp
syms = symbols("a:d A:D")
def _num(rterms):
# return the multiplier that will simplify the expression described
# by rterms [(sqrt arg, coeff), ... ]
a, b, c, d, A, B, C, D = syms
if len(rterms) == 2:
reps = dict(list(zip([A, a, B, b], [j for i in rterms for j in i])))
return (
sqrt(A)*a - sqrt(B)*b).xreplace(reps)
if len(rterms) == 3:
reps = dict(list(zip([A, a, B, b, C, c], [j for i in rterms for j in i])))
return (
(sqrt(A)*a + sqrt(B)*b - sqrt(C)*c)*(2*sqrt(A)*sqrt(B)*a*b - A*a**2 -
B*b**2 + C*c**2)).xreplace(reps)
elif len(rterms) == 4:
reps = dict(list(zip([A, a, B, b, C, c, D, d], [j for i in rterms for j in i])))
return ((sqrt(A)*a + sqrt(B)*b - sqrt(C)*c - sqrt(D)*d)*(2*sqrt(A)*sqrt(B)*a*b
- A*a**2 - B*b**2 - 2*sqrt(C)*sqrt(D)*c*d + C*c**2 +
D*d**2)*(-8*sqrt(A)*sqrt(B)*sqrt(C)*sqrt(D)*a*b*c*d + A**2*a**4 -
2*A*B*a**2*b**2 - 2*A*C*a**2*c**2 - 2*A*D*a**2*d**2 + B**2*b**4 -
2*B*C*b**2*c**2 - 2*B*D*b**2*d**2 + C**2*c**4 - 2*C*D*c**2*d**2 +
D**2*d**4)).xreplace(reps)
elif len(rterms) == 1:
return sqrt(rterms[0][0])
else:
raise NotImplementedError
def ispow2(d, log2=False):
if not d.is_Pow:
return False
e = d.exp
if e.is_Rational and e.q == 2 or symbolic and denom(e) == 2:
return True
if log2:
q = 1
if e.is_Rational:
q = e.q
elif symbolic:
d = denom(e)
if d.is_Integer:
q = d
if q != 1 and log(q, 2).is_Integer:
return True
return False
def handle(expr):
# Handle first reduces to the case
# expr = 1/d, where d is an add, or d is base**p/2.
# We do this by recursively calling handle on each piece.
from sympy.simplify.simplify import nsimplify
n, d = fraction(expr)
if expr.is_Atom or (d.is_Atom and n.is_Atom):
return expr
elif not n.is_Atom:
n = n.func(*[handle(a) for a in n.args])
return _unevaluated_Mul(n, handle(1/d))
elif n is not S.One:
return _unevaluated_Mul(n, handle(1/d))
elif d.is_Mul:
return _unevaluated_Mul(*[handle(1/d) for d in d.args])
# By this step, expr is 1/d, and d is not a mul.
if not symbolic and d.free_symbols:
return expr
if ispow2(d):
d2 = sqrtdenest(sqrt(d.base))**numer(d.exp)
if d2 != d:
return handle(1/d2)
elif d.is_Pow and (d.exp.is_integer or d.base.is_positive):
# (1/d**i) = (1/d)**i
return handle(1/d.base)**d.exp
if not (d.is_Add or ispow2(d)):
return 1/d.func(*[handle(a) for a in d.args])
# handle 1/d treating d as an Add (though it may not be)
keep = True # keep changes that are made
# flatten it and collect radicals after checking for special
# conditions
d = _mexpand(d)
# did it change?
if d.is_Atom:
return 1/d
# is it a number that might be handled easily?
if d.is_number:
_d = nsimplify(d)
if _d.is_Number and _d.equals(d):
return 1/_d
while True:
# collect similar terms
collected = defaultdict(list)
for m in Add.make_args(d): # d might have become non-Add
p2 = []
other = []
for i in Mul.make_args(m):
if ispow2(i, log2=True):
p2.append(i.base if i.exp is S.Half else i.base**(2*i.exp))
elif i is S.ImaginaryUnit:
p2.append(S.NegativeOne)
else:
other.append(i)
collected[tuple(ordered(p2))].append(Mul(*other))
rterms = list(ordered(list(collected.items())))
rterms = [(Mul(*i), Add(*j)) for i, j in rterms]
nrad = len(rterms) - (1 if rterms[0][0] is S.One else 0)
if nrad < 1:
break
elif nrad > max_terms:
# there may have been invalid operations leading to this point
# so don't keep changes, e.g. this expression is troublesome
# in collecting terms so as not to raise the issue of 2834:
# r = sqrt(sqrt(5) + 5)
# eq = 1/(sqrt(5)*r + 2*sqrt(5)*sqrt(-sqrt(5) + 5) + 5*r)
keep = False
break
if len(rterms) > 4:
# in general, only 4 terms can be removed with repeated squaring
# but other considerations can guide selection of radical terms
# so that radicals are removed
if all([x.is_Integer and (y**2).is_Rational for x, y in rterms]):
nd, d = rad_rationalize(S.One, Add._from_args(
[sqrt(x)*y for x, y in rterms]))
n *= nd
else:
# is there anything else that might be attempted?
keep = False
break
from sympy.simplify.powsimp import powsimp, powdenest
num = powsimp(_num(rterms))
n *= num
d *= num
d = powdenest(_mexpand(d), force=symbolic)
if d.is_Atom:
break
if not keep:
return expr
return _unevaluated_Mul(n, 1/d)
coeff, expr = expr.as_coeff_Add()
expr = expr.normal()
old = fraction(expr)
n, d = fraction(handle(expr))
if old != (n, d):
if not d.is_Atom:
was = (n, d)
n = signsimp(n, evaluate=False)
d = signsimp(d, evaluate=False)
u = Factors(_unevaluated_Mul(n, 1/d))
u = _unevaluated_Mul(*[k**v for k, v in u.factors.items()])
n, d = fraction(u)
if old == (n, d):
n, d = was
n = expand_mul(n)
if d.is_Number or d.is_Add:
n2, d2 = fraction(gcd_terms(_unevaluated_Mul(n, 1/d)))
if d2.is_Number or (d2.count_ops() <= d.count_ops()):
n, d = [signsimp(i) for i in (n2, d2)]
if n.is_Mul and n.args[0].is_Number:
n = n.func(*n.args)
return coeff + _unevaluated_Mul(n, 1/d)
def test_issue_18991():
A = MatrixSymbol('A', 2, 2)
assert signsimp(-A * A - A) == -A * A - A
def test_DiracDelta():
assert DiracDelta(1) == 0
assert DiracDelta(5.1) == 0
assert DiracDelta(-pi) == 0
assert DiracDelta(5, 7) == 0
assert DiracDelta(i) == 0
assert DiracDelta(j) == 0
assert DiracDelta(k) == 0
assert DiracDelta(nan) is nan
assert DiracDelta(0).func is DiracDelta
assert DiracDelta(x).func is DiracDelta
# FIXME: this is generally undefined @ x=0
# But then limit(Delta(c)*Heaviside(x),x,-oo)
# need's to be implemented.
# assert 0*DiracDelta(x) == 0
assert adjoint(DiracDelta(x)) == DiracDelta(x)
assert adjoint(DiracDelta(x - y)) == DiracDelta(x - y)
assert conjugate(DiracDelta(x)) == DiracDelta(x)
assert conjugate(DiracDelta(x - y)) == DiracDelta(x - y)
assert transpose(DiracDelta(x)) == DiracDelta(x)
assert transpose(DiracDelta(x - y)) == DiracDelta(x - y)
assert DiracDelta(x).diff(x) == DiracDelta(x, 1)
assert DiracDelta(x, 1).diff(x) == DiracDelta(x, 2)
assert DiracDelta(x).is_simple(x) is True
assert DiracDelta(3*x).is_simple(x) is True
assert DiracDelta(x**2).is_simple(x) is False
assert DiracDelta(sqrt(x)).is_simple(x) is False
assert DiracDelta(x).is_simple(y) is False
assert DiracDelta(x*y).expand(diracdelta=True, wrt=x) == DiracDelta(x)/abs(y)
assert DiracDelta(x*y).expand(diracdelta=True, wrt=y) == DiracDelta(y)/abs(x)
assert DiracDelta(x**2*y).expand(diracdelta=True, wrt=x) == DiracDelta(x**2*y)
assert DiracDelta(y).expand(diracdelta=True, wrt=x) == DiracDelta(y)
assert DiracDelta((x - 1)*(x - 2)*(x - 3)).expand(diracdelta=True, wrt=x) == (
DiracDelta(x - 3)/2 + DiracDelta(x - 2) + DiracDelta(x - 1)/2)
assert DiracDelta(2*x) != DiracDelta(x) # scaling property
assert DiracDelta(x) == DiracDelta(-x) # even function
assert DiracDelta(-x, 2) == DiracDelta(x, 2)
assert DiracDelta(-x, 1) == -DiracDelta(x, 1) # odd deriv is odd
assert DiracDelta(-oo*x) == DiracDelta(oo*x)
assert DiracDelta(x - y) != DiracDelta(y - x)
assert signsimp(DiracDelta(x - y) - DiracDelta(y - x)) == 0
with warns_deprecated_sympy():
assert DiracDelta(x*y).simplify(x) == DiracDelta(x)/abs(y)
with warns_deprecated_sympy():
assert DiracDelta(x*y).simplify(y) == DiracDelta(y)/abs(x)
with warns_deprecated_sympy():
assert DiracDelta(x**2*y).simplify(x) == DiracDelta(x**2*y)
with warns_deprecated_sympy():
assert DiracDelta(y).simplify(x) == DiracDelta(y)
with warns_deprecated_sympy():
assert DiracDelta((x - 1)*(x - 2)*(x - 3)).simplify(x) == (
DiracDelta(x - 3)/2 + DiracDelta(x - 2) + DiracDelta(x - 1)/2)
raises(ArgumentIndexError, lambda: DiracDelta(x).fdiff(2))
raises(ValueError, lambda: DiracDelta(x, -1))
raises(ValueError, lambda: DiracDelta(I))
raises(ValueError, lambda: DiracDelta(2 + 3*I))
def __new__(cls, expr, *variables, **assumptions):
global numderiv
global derarr
derarr.append(expr)
expr = sympify(expr)
# There are no variables, we differentiate wrt all of the free symbols
# in expr.
if not variables:
variables = expr.free_symbols
if len(variables) != 1:
from sympy.utilities.misc import filldedent
raise ValueError(filldedent('''
Since there is more than one variable in the
expression, the variable(s) of differentiation
must be supplied to differentiate %s''' % expr))
# Standardize the variables by sympifying them and making appending a
# count of 1 if there is only one variable: diff(e,x)->diff(e,x,1).
variables = list(sympify(variables))
if not variables[-1].is_Integer or len(variables) == 1:
variables.append(S.One)
# Split the list of variables into a list of the variables we are diff
# wrt, where each element of the list has the form (s, count) where
# s is the entity to diff wrt and count is the order of the
# derivative.
variable_count = []
all_zero = True
i = 0
while i < len(variables) - 1: # process up to final Integer
v, count = variables[i: i + 2]
iwas = i
if v._diff_wrt:
# We need to test the more specific case of count being an
# Integer first.
if count.is_Integer:
count = int(count)
i += 2
elif count._diff_wrt:
count = 1
i += 1
"""
if i == iwas: # didn't get an update because of bad input
from sympy.utilities.misc import filldedent
raise ValueError(filldedent('''
Can\'t differentiate wrt the variable: %s, %s''' % (v, count)))
"""
if all_zero and not count == 0:
all_zero = False
if count:
variable_count.append((v, count))
# We make a special case for 0th derivative, because there is no
# good way to unambiguously print this.
if all_zero:
return expr
# Pop evaluate because it is not really an assumption and we will need
# to track it carefully below.
evaluate = assumptions.pop('evaluate', False)
# Look for a quick exit if there are symbols that don't appear in
# expression at all. Note, this cannnot check non-symbols like
# functions and Derivatives as those can be created by intermediate
# derivatives.
if evaluate:
symbol_set = set(sc[0] for sc in variable_count if sc[0].is_Symbol)
if symbol_set.difference(expr.free_symbols):
return S.Zero
# We make a generator so as to only generate a variable when necessary.
# If a high order of derivative is requested and the expr becomes 0
# after a few differentiations, then we won't need the other variables.
variablegen = (v for v, count in variable_count for i in xrange(count))
# If we can't compute the derivative of expr (but we wanted to) and
# expr is itself not a Derivative, finish building an unevaluated
# derivative class by calling Expr.__new__.
if (not (hasattr(expr, '_eval_derivative') and evaluate) and
(not isinstance(expr, Derivative))):
variables = list(variablegen)
# If we wanted to evaluate, we sort the variables into standard
# order for later comparisons. This is too aggressive if evaluate
# is False, so we don't do it in that case.
if evaluate:
#TODO: check if assumption of discontinuous derivatives exist
variables = cls._sort_variables(variables)
# Here we *don't* need to reinject evaluate into assumptions
# because we are done with it and it is not an assumption that
# Expr knows about.
obj = Expr.__new__(cls, expr, *variables, **assumptions)
#print("O",obj)
return obj
# Compute the derivative now by repeatedly calling the
# _eval_derivative method of expr for each variable. When this method
# returns None, the derivative couldn't be computed wrt that variable
# and we save the variable for later.
unhandled_variables = []
# Once we encouter a non_symbol that is unhandled, we stop taking
# derivatives entirely. This is because derivatives wrt functions
# don't commute with derivatives wrt symbols and we can't safely
# continue.
unhandled_non_symbol = False
nderivs = 0 # how many derivatives were performed
#print("varibale",variablegen)
for v in variablegen:
is_symbol = v.is_Symbol
if unhandled_non_symbol:
obj = None
else:
if not is_symbol:
new_v = C.Dummy('xi_%i' % i)
new_v.dummy_index = hash(v)
expr = expr.subs(v, new_v)
old_v = v
v = new_v
numderiv+=1
obj = expr._eval_derivative(v)
numderiv-=1
nderivs += 1
if not is_symbol:
if obj is not None:
#print("first",obj)
obj = obj.subs(v, old_v)
#print("second",obj)
#print("v ",v,"old ",old_v)
v = old_v
#print("----expr is",obj)
if obj is None:
#print ("yeyyyyy")
unhandled_variables.append(v)
if not is_symbol:
unhandled_non_symbol = True
elif obj is S.Zero:
return S.Zero
else:
expr = obj
#print("---expr is",expr.args[0:])
if unhandled_variables:
unhandled_variables = cls._sort_variables(unhandled_variables)
#print("1",expr)
expr = Expr.__new__(cls, expr, *unhandled_variables, **assumptions)
else:
# We got a Derivative at the end of it all, and we rebuild it by
# sorting its variables.
#print(isinstance(expr,Derivative))
if isinstance(expr, Derivative):
#print("#",expr.args[0])
expr = cls(
expr.args[0], *cls._sort_variables(expr.args[1:])
)
#print("##",expr)
#print("--expr is",expr)
#print("-expr is",expr)
if nderivs > 1 and assumptions.get('simplify', True):
from sympy.core.exprtools import factor_terms
from sympy.simplify.simplify import signsimp
expr = factor_terms(signsimp(expr))
#print("expr is",expr)
if numderiv==0: # no of recursive derivatives
from sympy.printing.pretty import pprint
temparr = derarr # so that following derivative does not causes infinite loop because it will keep adding to derarr.
derarr=[] # prevents infinite loop
for i in temparr:
pprint(Derivative(i,'x',evaluate=False))
derarr = [] # empties, so that next derivative expr find it empty..
return expr
def eval(cls, arg):
from sympy.simplify.simplify import signsimp
from sympy.core.function import expand_mul
if hasattr(arg, '_eval_Abs'):
obj = arg._eval_Abs()
if obj is not None:
return obj
if not isinstance(arg, Expr):
raise TypeError("Bad argument type for Abs(): %s" % type(arg))
# handle what we can
arg = signsimp(arg, evaluate=False)
if arg.is_Mul:
known = []
unk = []
for t in arg.args:
tnew = cls(t)
if tnew.func is cls:
unk.append(tnew.args[0])
else:
known.append(tnew)
known = Mul(*known)
unk = cls(Mul(*unk), evaluate=False) if unk else S.One
return known * unk
if arg is S.NaN:
return S.NaN
if arg.is_Pow:
base, exponent = arg.as_base_exp()
if base.is_real:
if exponent.is_integer:
if exponent.is_even:
return arg
if base is S.NegativeOne:
return S.One
if base.func is cls and exponent is S.NegativeOne:
return arg
return Abs(base)**exponent
if base.is_positive == True:
return base**re(exponent)
return (-base)**re(exponent) * exp(-S.Pi * im(exponent))
if isinstance(arg, exp):
return exp(re(arg.args[0]))
if isinstance(arg, AppliedUndef):
return
if arg.is_Add and arg.has(S.Infinity, S.NegativeInfinity):
if any(a.is_infinite for a in arg.as_real_imag()):
return S.Infinity
if arg.is_zero:
return S.Zero
if arg.is_nonnegative:
return arg
if arg.is_nonpositive:
return -arg
if arg.is_imaginary:
arg2 = -S.ImaginaryUnit * arg
if arg2.is_nonnegative:
return arg2
# reject result if all new conjugates are just wrappers around
# an expression that was already in the arg
conj = arg.conjugate()
new_conj = conj.atoms(conjugate) - arg.atoms(conjugate)
if new_conj and all(arg.has(i.args[0]) for i in new_conj):
return
if arg != conj and arg != -conj:
ignore = arg.atoms(Abs)
abs_free_arg = arg.xreplace(
dict([(i, Dummy(real=True)) for i in ignore]))
unk = [a for a in abs_free_arg.free_symbols if a.is_real is None]
if not unk or not all(conj.has(conjugate(u)) for u in unk):
return sqrt(expand_mul(arg * conj))
