You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.

773 lines
23 KiB

5 months ago
"""
Handlers for predicates related to set membership: integer, rational, etc.
"""
from sympy.assumptions import Q, ask
from sympy.core import Add, Basic, Expr, Mul, Pow, S
from sympy.core.numbers import (AlgebraicNumber, ComplexInfinity, Exp1, Float,
GoldenRatio, ImaginaryUnit, Infinity, Integer, NaN, NegativeInfinity,
Number, NumberSymbol, Pi, pi, Rational, TribonacciConstant, E)
from sympy.core.logic import fuzzy_bool
from sympy.functions import (Abs, acos, acot, asin, atan, cos, cot, exp, im,
log, re, sin, tan)
from sympy.core.numbers import I
from sympy.core.relational import Eq
from sympy.functions.elementary.complexes import conjugate
from sympy.matrices import Determinant, MatrixBase, Trace
from sympy.matrices.expressions.matexpr import MatrixElement
from sympy.multipledispatch import MDNotImplementedError
from .common import test_closed_group
from ..predicates.sets import (IntegerPredicate, RationalPredicate,
IrrationalPredicate, RealPredicate, ExtendedRealPredicate,
HermitianPredicate, ComplexPredicate, ImaginaryPredicate,
AntihermitianPredicate, AlgebraicPredicate)
# IntegerPredicate
def _IntegerPredicate_number(expr, assumptions):
# helper function
try:
i = int(expr.round())
if not (expr - i).equals(0):
raise TypeError
return True
except TypeError:
return False
@IntegerPredicate.register_many(int, Integer) # type:ignore
def _(expr, assumptions):
return True
@IntegerPredicate.register_many(Exp1, GoldenRatio, ImaginaryUnit, Infinity,
NegativeInfinity, Pi, Rational, TribonacciConstant)
def _(expr, assumptions):
return False
@IntegerPredicate.register(Expr)
def _(expr, assumptions):
ret = expr.is_integer
if ret is None:
raise MDNotImplementedError
return ret
@IntegerPredicate.register_many(Add, Pow)
def _(expr, assumptions):
"""
* Integer + Integer -> Integer
* Integer + !Integer -> !Integer
* !Integer + !Integer -> ?
"""
if expr.is_number:
return _IntegerPredicate_number(expr, assumptions)
return test_closed_group(expr, assumptions, Q.integer)
@IntegerPredicate.register(Mul)
def _(expr, assumptions):
"""
* Integer*Integer -> Integer
* Integer*Irrational -> !Integer
* Odd/Even -> !Integer
* Integer*Rational -> ?
"""
if expr.is_number:
return _IntegerPredicate_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
return _output
@IntegerPredicate.register(Abs)
def _(expr, assumptions):
return ask(Q.integer(expr.args[0]), assumptions)
@IntegerPredicate.register_many(Determinant, MatrixElement, Trace)
def _(expr, assumptions):
return ask(Q.integer_elements(expr.args[0]), assumptions)
# RationalPredicate
@RationalPredicate.register(Rational)
def _(expr, assumptions):
return True
@RationalPredicate.register(Float)
def _(expr, assumptions):
return None
@RationalPredicate.register_many(Exp1, GoldenRatio, ImaginaryUnit, Infinity,
NegativeInfinity, Pi, TribonacciConstant)
def _(expr, assumptions):
return False
@RationalPredicate.register(Expr)
def _(expr, assumptions):
ret = expr.is_rational
if ret is None:
raise MDNotImplementedError
return ret
@RationalPredicate.register_many(Add, Mul)
def _(expr, assumptions):
"""
* Rational + Rational -> Rational
* Rational + !Rational -> !Rational
* !Rational + !Rational -> ?
"""
if expr.is_number:
if expr.as_real_imag()[1]:
return False
return test_closed_group(expr, assumptions, Q.rational)
@RationalPredicate.register(Pow)
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
@RationalPredicate.register_many(asin, atan, cos, sin, tan)
def _(expr, assumptions):
x = expr.args[0]
if ask(Q.rational(x), assumptions):
return ask(~Q.nonzero(x), assumptions)
@RationalPredicate.register(exp)
def _(expr, assumptions):
x = expr.exp
if ask(Q.rational(x), assumptions):
return ask(~Q.nonzero(x), assumptions)
@RationalPredicate.register_many(acot, cot)
def _(expr, assumptions):
x = expr.args[0]
if ask(Q.rational(x), assumptions):
return False
@RationalPredicate.register_many(acos, log)
def _(expr, assumptions):
x = expr.args[0]
if ask(Q.rational(x), assumptions):
return ask(~Q.nonzero(x - 1), assumptions)
# IrrationalPredicate
@IrrationalPredicate.register(Expr)
def _(expr, assumptions):
ret = expr.is_irrational
if ret is None:
raise MDNotImplementedError
return ret
@IrrationalPredicate.register(Basic)
def _(expr, assumptions):
_real = ask(Q.real(expr), assumptions)
if _real:
_rational = ask(Q.rational(expr), assumptions)
if _rational is None:
return None
return not _rational
else:
return _real
# RealPredicate
def _RealPredicate_number(expr, assumptions):
# let as_real_imag() work first since the expression may
# be simpler to evaluate
i = expr.as_real_imag()[1].evalf(2)
if i._prec != 1:
return not i
# allow None to be returned if we couldn't show for sure
# that i was 0
@RealPredicate.register_many(Abs, Exp1, Float, GoldenRatio, im, Pi, Rational,
re, TribonacciConstant)
def _(expr, assumptions):
return True
@RealPredicate.register_many(ImaginaryUnit, Infinity, NegativeInfinity)
def _(expr, assumptions):
return False
@RealPredicate.register(Expr)
def _(expr, assumptions):
ret = expr.is_real
if ret is None:
raise MDNotImplementedError
return ret
@RealPredicate.register(Add)
def _(expr, assumptions):
"""
* Real + Real -> Real
* Real + (Complex & !Real) -> !Real
"""
if expr.is_number:
return _RealPredicate_number(expr, assumptions)
return test_closed_group(expr, assumptions, Q.real)
@RealPredicate.register(Mul)
def _(expr, assumptions):
"""
* Real*Real -> Real
* Real*Imaginary -> !Real
* Imaginary*Imaginary -> Real
"""
if expr.is_number:
return _RealPredicate_number(expr, assumptions)
result = True
for arg in expr.args:
if ask(Q.real(arg), assumptions):
pass
elif ask(Q.imaginary(arg), assumptions):
result = result ^ True
else:
break
else:
return result
@RealPredicate.register(Pow)
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((S.NegativeOne**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
@RealPredicate.register_many(cos, sin)
def _(expr, assumptions):
if ask(Q.real(expr.args[0]), assumptions):
return True
@RealPredicate.register(exp)
def _(expr, assumptions):
return ask(
Q.integer(expr.exp/I/pi) | Q.real(expr.exp), assumptions
)
@RealPredicate.register(log)
def _(expr, assumptions):
return ask(Q.positive(expr.args[0]), assumptions)
@RealPredicate.register_many(Determinant, MatrixElement, Trace)
def _(expr, assumptions):
return ask(Q.real_elements(expr.args[0]), assumptions)
# ExtendedRealPredicate
@ExtendedRealPredicate.register(object)
def _(expr, assumptions):
return ask(Q.negative_infinite(expr)
| Q.negative(expr)
| Q.zero(expr)
| Q.positive(expr)
| Q.positive_infinite(expr),
assumptions)
@ExtendedRealPredicate.register_many(Infinity, NegativeInfinity)
def _(expr, assumptions):
return True
@ExtendedRealPredicate.register_many(Add, Mul, Pow) # type:ignore
def _(expr, assumptions):
return test_closed_group(expr, assumptions, Q.extended_real)
# HermitianPredicate
@HermitianPredicate.register(object) # type:ignore
def _(expr, assumptions):
if isinstance(expr, MatrixBase):
return None
return ask(Q.real(expr), assumptions)
@HermitianPredicate.register(Add) # type:ignore
def _(expr, assumptions):
"""
* Hermitian + Hermitian -> Hermitian
* Hermitian + !Hermitian -> !Hermitian
"""
if expr.is_number:
raise MDNotImplementedError
return test_closed_group(expr, assumptions, Q.hermitian)
@HermitianPredicate.register(Mul) # type:ignore
def _(expr, assumptions):
"""
As long as there is at most only one noncommutative term:
* Hermitian*Hermitian -> Hermitian
* Hermitian*Antihermitian -> !Hermitian
* Antihermitian*Antihermitian -> Hermitian
"""
if expr.is_number:
raise MDNotImplementedError
nccount = 0
result = True
for arg in expr.args:
if ask(Q.antihermitian(arg), assumptions):
result = result ^ True
elif not ask(Q.hermitian(arg), assumptions):
break
if ask(~Q.commutative(arg), assumptions):
nccount += 1
if nccount > 1:
break
else:
return result
@HermitianPredicate.register(Pow) # type:ignore
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
@HermitianPredicate.register_many(cos, sin) # type:ignore
def _(expr, assumptions):
if ask(Q.hermitian(expr.args[0]), assumptions):
return True
raise MDNotImplementedError
@HermitianPredicate.register(exp) # type:ignore
def _(expr, assumptions):
if ask(Q.hermitian(expr.exp), assumptions):
return True
raise MDNotImplementedError
@HermitianPredicate.register(MatrixBase) # type:ignore
def _(mat, assumptions):
rows, cols = mat.shape
ret_val = True
for i in range(rows):
for j in range(i, cols):
cond = fuzzy_bool(Eq(mat[i, j], conjugate(mat[j, i])))
if cond is None:
ret_val = None
if cond == False:
return False
if ret_val is None:
raise MDNotImplementedError
return ret_val
# ComplexPredicate
@ComplexPredicate.register_many(Abs, cos, exp, im, ImaginaryUnit, log, Number, # type:ignore
NumberSymbol, re, sin)
def _(expr, assumptions):
return True
@ComplexPredicate.register_many(Infinity, NegativeInfinity) # type:ignore
def _(expr, assumptions):
return False
@ComplexPredicate.register(Expr) # type:ignore
def _(expr, assumptions):
ret = expr.is_complex
if ret is None:
raise MDNotImplementedError
return ret
@ComplexPredicate.register_many(Add, Mul) # type:ignore
def _(expr, assumptions):
return test_closed_group(expr, assumptions, Q.complex)
@ComplexPredicate.register(Pow) # type:ignore
def _(expr, assumptions):
if expr.base == E:
return True
return test_closed_group(expr, assumptions, Q.complex)
@ComplexPredicate.register_many(Determinant, MatrixElement, Trace) # type:ignore
def _(expr, assumptions):
return ask(Q.complex_elements(expr.args[0]), assumptions)
@ComplexPredicate.register(NaN) # type:ignore
def _(expr, assumptions):
return None
# ImaginaryPredicate
def _Imaginary_number(expr, assumptions):
# let as_real_imag() work first since the expression may
# be simpler to evaluate
r = expr.as_real_imag()[0].evalf(2)
if r._prec != 1:
return not r
# allow None to be returned if we couldn't show for sure
# that r was 0
@ImaginaryPredicate.register(ImaginaryUnit) # type:ignore
def _(expr, assumptions):
return True
@ImaginaryPredicate.register(Expr) # type:ignore
def _(expr, assumptions):
ret = expr.is_imaginary
if ret is None:
raise MDNotImplementedError
return ret
@ImaginaryPredicate.register(Add) # type:ignore
def _(expr, assumptions):
"""
* Imaginary + Imaginary -> Imaginary
* Imaginary + Complex -> ?
* Imaginary + Real -> !Imaginary
"""
if expr.is_number:
return _Imaginary_number(expr, assumptions)
reals = 0
for arg in expr.args:
if ask(Q.imaginary(arg), assumptions):
pass
elif ask(Q.real(arg), assumptions):
reals += 1
else:
break
else:
if reals == 0:
return True
if reals in (1, len(expr.args)):
# two reals could sum 0 thus giving an imaginary
return False
@ImaginaryPredicate.register(Mul) # type:ignore
def _(expr, assumptions):
"""
* Real*Imaginary -> Imaginary
* Imaginary*Imaginary -> Real
"""
if expr.is_number:
return _Imaginary_number(expr, assumptions)
result = False
reals = 0
for arg in expr.args:
if ask(Q.imaginary(arg), assumptions):
result = result ^ True
elif not ask(Q.real(arg), assumptions):
break
else:
if reals == len(expr.args):
return False
return result
@ImaginaryPredicate.register(Pow) # type:ignore
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
@ImaginaryPredicate.register(log) # type:ignore
def _(expr, assumptions):
if ask(Q.real(expr.args[0]), assumptions):
if ask(Q.positive(expr.args[0]), assumptions):
return False
return
# XXX it should be enough to do
# return ask(Q.nonpositive(expr.args[0]), assumptions)
# but ask(Q.nonpositive(exp(x)), Q.imaginary(x)) -> None;
# it should return True since exp(x) will be either 0 or complex
if expr.args[0].func == exp or (expr.args[0].is_Pow and expr.args[0].base == E):
if expr.args[0].exp in [I, -I]:
return True
im = ask(Q.imaginary(expr.args[0]), assumptions)
if im is False:
return False
@ImaginaryPredicate.register(exp) # type:ignore
def _(expr, assumptions):
a = expr.exp/I/pi
return ask(Q.integer(2*a) & ~Q.integer(a), assumptions)
@ImaginaryPredicate.register_many(Number, NumberSymbol) # type:ignore
def _(expr, assumptions):
return not (expr.as_real_imag()[1] == 0)
@ImaginaryPredicate.register(NaN) # type:ignore
def _(expr, assumptions):
return None
# AntihermitianPredicate
@AntihermitianPredicate.register(object) # type:ignore
def _(expr, assumptions):
if isinstance(expr, MatrixBase):
return None
if ask(Q.zero(expr), assumptions):
return True
return ask(Q.imaginary(expr), assumptions)
@AntihermitianPredicate.register(Add) # type:ignore
def _(expr, assumptions):
"""
* Antihermitian + Antihermitian -> Antihermitian
* Antihermitian + !Antihermitian -> !Antihermitian
"""
if expr.is_number:
raise MDNotImplementedError
return test_closed_group(expr, assumptions, Q.antihermitian)
@AntihermitianPredicate.register(Mul) # type:ignore
def _(expr, assumptions):
"""
As long as there is at most only one noncommutative term:
* Hermitian*Hermitian -> !Antihermitian
* Hermitian*Antihermitian -> Antihermitian
* Antihermitian*Antihermitian -> !Antihermitian
"""
if expr.is_number:
raise MDNotImplementedError
nccount = 0
result = False
for arg in expr.args:
if ask(Q.antihermitian(arg), assumptions):
result = result ^ True
elif not ask(Q.hermitian(arg), assumptions):
break
if ask(~Q.commutative(arg), assumptions):
nccount += 1
if nccount > 1:
break
else:
return result
@AntihermitianPredicate.register(Pow) # type:ignore
def _(expr, assumptions):
"""
* Hermitian**Integer -> !Antihermitian
* Antihermitian**Even -> !Antihermitian
* Antihermitian**Odd -> Antihermitian
"""
if expr.is_number:
raise MDNotImplementedError
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
raise MDNotImplementedError
@AntihermitianPredicate.register(MatrixBase) # type:ignore
def _(mat, assumptions):
rows, cols = mat.shape
ret_val = True
for i in range(rows):
for j in range(i, cols):
cond = fuzzy_bool(Eq(mat[i, j], -conjugate(mat[j, i])))
if cond is None:
ret_val = None
if cond == False:
return False
if ret_val is None:
raise MDNotImplementedError
return ret_val
# AlgebraicPredicate
@AlgebraicPredicate.register_many(AlgebraicNumber, Float, GoldenRatio, # type:ignore
ImaginaryUnit, TribonacciConstant)
def _(expr, assumptions):
return True
@AlgebraicPredicate.register_many(ComplexInfinity, Exp1, Infinity, # type:ignore
NegativeInfinity, Pi)
def _(expr, assumptions):
return False
@AlgebraicPredicate.register_many(Add, Mul) # type:ignore
def _(expr, assumptions):
return test_closed_group(expr, assumptions, Q.algebraic)
@AlgebraicPredicate.register(Pow) # type:ignore
def _(expr, assumptions):
if expr.base == E:
if ask(Q.algebraic(expr.exp), assumptions):
return ask(~Q.nonzero(expr.exp), assumptions)
return
return expr.exp.is_Rational and ask(Q.algebraic(expr.base), assumptions)
@AlgebraicPredicate.register(Rational) # type:ignore
def _(expr, assumptions):
return expr.q != 0
@AlgebraicPredicate.register_many(asin, atan, cos, sin, tan) # type:ignore
def _(expr, assumptions):
x = expr.args[0]
if ask(Q.algebraic(x), assumptions):
return ask(~Q.nonzero(x), assumptions)
@AlgebraicPredicate.register(exp) # type:ignore
def _(expr, assumptions):
x = expr.exp
if ask(Q.algebraic(x), assumptions):
return ask(~Q.nonzero(x), assumptions)
@AlgebraicPredicate.register_many(acot, cot) # type:ignore
def _(expr, assumptions):
x = expr.args[0]
if ask(Q.algebraic(x), assumptions):
return False
@AlgebraicPredicate.register_many(acos, log) # type:ignore
def _(expr, assumptions):
x = expr.args[0]
if ask(Q.algebraic(x), assumptions):
return ask(~Q.nonzero(x - 1), assumptions)