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626 lines
19 KiB
626 lines
19 KiB
from typing import Tuple as tTuple
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from sympy.core.basic import Basic
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from sympy.core.expr import Expr
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from sympy.core import Add, S
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from sympy.core.evalf import get_integer_part, PrecisionExhausted
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from sympy.core.function import Function
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from sympy.core.logic import fuzzy_or
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from sympy.core.numbers import Integer
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from sympy.core.relational import Gt, Lt, Ge, Le, Relational, is_eq
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from sympy.core.symbol import Symbol
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from sympy.core.sympify import _sympify
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from sympy.functions.elementary.complexes import im, re
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from sympy.multipledispatch import dispatch
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###############################################################################
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######################### FLOOR and CEILING FUNCTIONS #########################
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###############################################################################
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class RoundFunction(Function):
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"""Abstract base class for rounding functions."""
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args: tTuple[Expr]
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@classmethod
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def eval(cls, arg):
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v = cls._eval_number(arg)
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if v is not None:
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return v
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if arg.is_integer or arg.is_finite is False:
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return arg
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if arg.is_imaginary or (S.ImaginaryUnit*arg).is_real:
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i = im(arg)
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if not i.has(S.ImaginaryUnit):
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return cls(i)*S.ImaginaryUnit
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return cls(arg, evaluate=False)
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# Integral, numerical, symbolic part
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ipart = npart = spart = S.Zero
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# Extract integral (or complex integral) terms
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terms = Add.make_args(arg)
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for t in terms:
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if t.is_integer or (t.is_imaginary and im(t).is_integer):
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ipart += t
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elif t.has(Symbol):
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spart += t
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else:
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npart += t
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if not (npart or spart):
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return ipart
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# Evaluate npart numerically if independent of spart
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if npart and (
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not spart or
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npart.is_real and (spart.is_imaginary or (S.ImaginaryUnit*spart).is_real) or
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npart.is_imaginary and spart.is_real):
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try:
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r, i = get_integer_part(
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npart, cls._dir, {}, return_ints=True)
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ipart += Integer(r) + Integer(i)*S.ImaginaryUnit
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npart = S.Zero
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except (PrecisionExhausted, NotImplementedError):
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pass
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spart += npart
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if not spart:
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return ipart
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elif spart.is_imaginary or (S.ImaginaryUnit*spart).is_real:
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return ipart + cls(im(spart), evaluate=False)*S.ImaginaryUnit
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elif isinstance(spart, (floor, ceiling)):
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return ipart + spart
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else:
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return ipart + cls(spart, evaluate=False)
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@classmethod
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def _eval_number(cls, arg):
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raise NotImplementedError()
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def _eval_is_finite(self):
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return self.args[0].is_finite
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def _eval_is_real(self):
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return self.args[0].is_real
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def _eval_is_integer(self):
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return self.args[0].is_real
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class floor(RoundFunction):
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"""
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Floor is a univariate function which returns the largest integer
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value not greater than its argument. This implementation
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generalizes floor to complex numbers by taking the floor of the
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real and imaginary parts separately.
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Examples
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========
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>>> from sympy import floor, E, I, S, Float, Rational
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>>> floor(17)
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17
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>>> floor(Rational(23, 10))
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2
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>>> floor(2*E)
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5
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>>> floor(-Float(0.567))
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-1
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>>> floor(-I/2)
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-I
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>>> floor(S(5)/2 + 5*I/2)
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2 + 2*I
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See Also
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========
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sympy.functions.elementary.integers.ceiling
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References
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==========
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.. [1] "Concrete mathematics" by Graham, pp. 87
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.. [2] https://mathworld.wolfram.com/FloorFunction.html
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"""
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_dir = -1
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@classmethod
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def _eval_number(cls, arg):
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if arg.is_Number:
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return arg.floor()
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elif any(isinstance(i, j)
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for i in (arg, -arg) for j in (floor, ceiling)):
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return arg
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if arg.is_NumberSymbol:
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return arg.approximation_interval(Integer)[0]
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def _eval_as_leading_term(self, x, logx=None, cdir=0):
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from sympy.calculus.accumulationbounds import AccumBounds
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arg = self.args[0]
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arg0 = arg.subs(x, 0)
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r = self.subs(x, 0)
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if arg0 is S.NaN or isinstance(arg0, AccumBounds):
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arg0 = arg.limit(x, 0, dir='-' if re(cdir).is_negative else '+')
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r = floor(arg0)
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if arg0.is_finite:
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if arg0 == r:
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ndir = arg.dir(x, cdir=cdir)
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return r - 1 if ndir.is_negative else r
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else:
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return r
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return arg.as_leading_term(x, logx=logx, cdir=cdir)
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def _eval_nseries(self, x, n, logx, cdir=0):
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arg = self.args[0]
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arg0 = arg.subs(x, 0)
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r = self.subs(x, 0)
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if arg0 is S.NaN:
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arg0 = arg.limit(x, 0, dir='-' if re(cdir).is_negative else '+')
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r = floor(arg0)
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if arg0.is_infinite:
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from sympy.calculus.accumulationbounds import AccumBounds
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from sympy.series.order import Order
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s = arg._eval_nseries(x, n, logx, cdir)
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o = Order(1, (x, 0)) if n <= 0 else AccumBounds(-1, 0)
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return s + o
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if arg0 == r:
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ndir = arg.dir(x, cdir=cdir if cdir != 0 else 1)
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return r - 1 if ndir.is_negative else r
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else:
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return r
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def _eval_is_negative(self):
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return self.args[0].is_negative
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def _eval_is_nonnegative(self):
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return self.args[0].is_nonnegative
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def _eval_rewrite_as_ceiling(self, arg, **kwargs):
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return -ceiling(-arg)
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def _eval_rewrite_as_frac(self, arg, **kwargs):
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return arg - frac(arg)
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def __le__(self, other):
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other = S(other)
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if self.args[0].is_real:
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if other.is_integer:
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return self.args[0] < other + 1
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if other.is_number and other.is_real:
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return self.args[0] < ceiling(other)
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if self.args[0] == other and other.is_real:
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return S.true
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if other is S.Infinity and self.is_finite:
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return S.true
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return Le(self, other, evaluate=False)
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def __ge__(self, other):
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other = S(other)
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if self.args[0].is_real:
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if other.is_integer:
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return self.args[0] >= other
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if other.is_number and other.is_real:
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return self.args[0] >= ceiling(other)
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if self.args[0] == other and other.is_real:
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return S.false
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if other is S.NegativeInfinity and self.is_finite:
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return S.true
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return Ge(self, other, evaluate=False)
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def __gt__(self, other):
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other = S(other)
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if self.args[0].is_real:
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if other.is_integer:
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return self.args[0] >= other + 1
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if other.is_number and other.is_real:
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return self.args[0] >= ceiling(other)
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if self.args[0] == other and other.is_real:
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return S.false
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if other is S.NegativeInfinity and self.is_finite:
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return S.true
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return Gt(self, other, evaluate=False)
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def __lt__(self, other):
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other = S(other)
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if self.args[0].is_real:
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if other.is_integer:
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return self.args[0] < other
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if other.is_number and other.is_real:
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return self.args[0] < ceiling(other)
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if self.args[0] == other and other.is_real:
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return S.false
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if other is S.Infinity and self.is_finite:
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return S.true
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return Lt(self, other, evaluate=False)
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@dispatch(floor, Expr)
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def _eval_is_eq(lhs, rhs): # noqa:F811
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return is_eq(lhs.rewrite(ceiling), rhs) or \
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is_eq(lhs.rewrite(frac),rhs)
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class ceiling(RoundFunction):
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"""
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Ceiling is a univariate function which returns the smallest integer
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value not less than its argument. This implementation
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generalizes ceiling to complex numbers by taking the ceiling of the
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real and imaginary parts separately.
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Examples
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========
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>>> from sympy import ceiling, E, I, S, Float, Rational
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>>> ceiling(17)
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17
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>>> ceiling(Rational(23, 10))
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3
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>>> ceiling(2*E)
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6
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>>> ceiling(-Float(0.567))
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0
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>>> ceiling(I/2)
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I
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>>> ceiling(S(5)/2 + 5*I/2)
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3 + 3*I
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See Also
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========
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sympy.functions.elementary.integers.floor
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References
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==========
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.. [1] "Concrete mathematics" by Graham, pp. 87
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.. [2] https://mathworld.wolfram.com/CeilingFunction.html
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"""
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_dir = 1
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@classmethod
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def _eval_number(cls, arg):
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if arg.is_Number:
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return arg.ceiling()
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elif any(isinstance(i, j)
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for i in (arg, -arg) for j in (floor, ceiling)):
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return arg
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if arg.is_NumberSymbol:
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return arg.approximation_interval(Integer)[1]
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def _eval_as_leading_term(self, x, logx=None, cdir=0):
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from sympy.calculus.accumulationbounds import AccumBounds
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arg = self.args[0]
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arg0 = arg.subs(x, 0)
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r = self.subs(x, 0)
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if arg0 is S.NaN or isinstance(arg0, AccumBounds):
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arg0 = arg.limit(x, 0, dir='-' if re(cdir).is_negative else '+')
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r = ceiling(arg0)
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if arg0.is_finite:
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if arg0 == r:
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ndir = arg.dir(x, cdir=cdir)
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return r if ndir.is_negative else r + 1
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else:
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return r
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return arg.as_leading_term(x, logx=logx, cdir=cdir)
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def _eval_nseries(self, x, n, logx, cdir=0):
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arg = self.args[0]
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arg0 = arg.subs(x, 0)
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r = self.subs(x, 0)
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if arg0 is S.NaN:
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arg0 = arg.limit(x, 0, dir='-' if re(cdir).is_negative else '+')
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r = ceiling(arg0)
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if arg0.is_infinite:
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from sympy.calculus.accumulationbounds import AccumBounds
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from sympy.series.order import Order
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s = arg._eval_nseries(x, n, logx, cdir)
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o = Order(1, (x, 0)) if n <= 0 else AccumBounds(0, 1)
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return s + o
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if arg0 == r:
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ndir = arg.dir(x, cdir=cdir if cdir != 0 else 1)
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return r if ndir.is_negative else r + 1
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else:
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return r
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def _eval_rewrite_as_floor(self, arg, **kwargs):
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return -floor(-arg)
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def _eval_rewrite_as_frac(self, arg, **kwargs):
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return arg + frac(-arg)
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def _eval_is_positive(self):
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return self.args[0].is_positive
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def _eval_is_nonpositive(self):
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return self.args[0].is_nonpositive
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def __lt__(self, other):
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other = S(other)
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if self.args[0].is_real:
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if other.is_integer:
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return self.args[0] <= other - 1
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if other.is_number and other.is_real:
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return self.args[0] <= floor(other)
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if self.args[0] == other and other.is_real:
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return S.false
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if other is S.Infinity and self.is_finite:
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return S.true
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return Lt(self, other, evaluate=False)
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def __gt__(self, other):
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other = S(other)
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if self.args[0].is_real:
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if other.is_integer:
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return self.args[0] > other
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if other.is_number and other.is_real:
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return self.args[0] > floor(other)
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if self.args[0] == other and other.is_real:
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return S.false
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if other is S.NegativeInfinity and self.is_finite:
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return S.true
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return Gt(self, other, evaluate=False)
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def __ge__(self, other):
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other = S(other)
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if self.args[0].is_real:
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if other.is_integer:
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return self.args[0] > other - 1
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if other.is_number and other.is_real:
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return self.args[0] > floor(other)
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if self.args[0] == other and other.is_real:
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return S.true
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if other is S.NegativeInfinity and self.is_finite:
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return S.true
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return Ge(self, other, evaluate=False)
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def __le__(self, other):
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other = S(other)
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if self.args[0].is_real:
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if other.is_integer:
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return self.args[0] <= other
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if other.is_number and other.is_real:
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return self.args[0] <= floor(other)
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if self.args[0] == other and other.is_real:
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return S.false
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if other is S.Infinity and self.is_finite:
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return S.true
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return Le(self, other, evaluate=False)
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@dispatch(ceiling, Basic) # type:ignore
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def _eval_is_eq(lhs, rhs): # noqa:F811
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return is_eq(lhs.rewrite(floor), rhs) or is_eq(lhs.rewrite(frac),rhs)
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class frac(Function):
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r"""Represents the fractional part of x
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For real numbers it is defined [1]_ as
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.. math::
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x - \left\lfloor{x}\right\rfloor
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Examples
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========
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>>> from sympy import Symbol, frac, Rational, floor, I
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>>> frac(Rational(4, 3))
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1/3
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>>> frac(-Rational(4, 3))
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2/3
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returns zero for integer arguments
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>>> n = Symbol('n', integer=True)
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>>> frac(n)
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0
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rewrite as floor
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>>> x = Symbol('x')
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>>> frac(x).rewrite(floor)
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x - floor(x)
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for complex arguments
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>>> r = Symbol('r', real=True)
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>>> t = Symbol('t', real=True)
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>>> frac(t + I*r)
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I*frac(r) + frac(t)
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See Also
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========
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sympy.functions.elementary.integers.floor
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sympy.functions.elementary.integers.ceiling
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References
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===========
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.. [1] https://en.wikipedia.org/wiki/Fractional_part
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.. [2] https://mathworld.wolfram.com/FractionalPart.html
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"""
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@classmethod
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def eval(cls, arg):
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from sympy.calculus.accumulationbounds import AccumBounds
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def _eval(arg):
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if arg in (S.Infinity, S.NegativeInfinity):
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return AccumBounds(0, 1)
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if arg.is_integer:
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return S.Zero
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if arg.is_number:
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if arg is S.NaN:
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return S.NaN
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elif arg is S.ComplexInfinity:
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return S.NaN
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else:
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return arg - floor(arg)
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return cls(arg, evaluate=False)
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terms = Add.make_args(arg)
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real, imag = S.Zero, S.Zero
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for t in terms:
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# Two checks are needed for complex arguments
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# see issue-7649 for details
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if t.is_imaginary or (S.ImaginaryUnit*t).is_real:
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i = im(t)
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if not i.has(S.ImaginaryUnit):
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imag += i
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else:
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real += t
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else:
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real += t
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real = _eval(real)
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imag = _eval(imag)
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return real + S.ImaginaryUnit*imag
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def _eval_rewrite_as_floor(self, arg, **kwargs):
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return arg - floor(arg)
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def _eval_rewrite_as_ceiling(self, arg, **kwargs):
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return arg + ceiling(-arg)
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def _eval_is_finite(self):
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return True
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def _eval_is_real(self):
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return self.args[0].is_extended_real
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def _eval_is_imaginary(self):
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return self.args[0].is_imaginary
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def _eval_is_integer(self):
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return self.args[0].is_integer
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def _eval_is_zero(self):
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return fuzzy_or([self.args[0].is_zero, self.args[0].is_integer])
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def _eval_is_negative(self):
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return False
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def __ge__(self, other):
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if self.is_extended_real:
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other = _sympify(other)
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# Check if other <= 0
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if other.is_extended_nonpositive:
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return S.true
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# Check if other >= 1
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res = self._value_one_or_more(other)
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if res is not None:
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return not(res)
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return Ge(self, other, evaluate=False)
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def __gt__(self, other):
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if self.is_extended_real:
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other = _sympify(other)
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|
# Check if other < 0
|
|
res = self._value_one_or_more(other)
|
|
if res is not None:
|
|
return not(res)
|
|
# Check if other >= 1
|
|
if other.is_extended_negative:
|
|
return S.true
|
|
return Gt(self, other, evaluate=False)
|
|
|
|
def __le__(self, other):
|
|
if self.is_extended_real:
|
|
other = _sympify(other)
|
|
# Check if other < 0
|
|
if other.is_extended_negative:
|
|
return S.false
|
|
# Check if other >= 1
|
|
res = self._value_one_or_more(other)
|
|
if res is not None:
|
|
return res
|
|
return Le(self, other, evaluate=False)
|
|
|
|
def __lt__(self, other):
|
|
if self.is_extended_real:
|
|
other = _sympify(other)
|
|
# Check if other <= 0
|
|
if other.is_extended_nonpositive:
|
|
return S.false
|
|
# Check if other >= 1
|
|
res = self._value_one_or_more(other)
|
|
if res is not None:
|
|
return res
|
|
return Lt(self, other, evaluate=False)
|
|
|
|
def _value_one_or_more(self, other):
|
|
if other.is_extended_real:
|
|
if other.is_number:
|
|
res = other >= 1
|
|
if res and not isinstance(res, Relational):
|
|
return S.true
|
|
if other.is_integer and other.is_positive:
|
|
return S.true
|
|
|
|
def _eval_as_leading_term(self, x, logx=None, cdir=0):
|
|
from sympy.calculus.accumulationbounds import AccumBounds
|
|
arg = self.args[0]
|
|
arg0 = arg.subs(x, 0)
|
|
r = self.subs(x, 0)
|
|
|
|
if arg0.is_finite:
|
|
if r.is_zero:
|
|
ndir = arg.dir(x, cdir=cdir)
|
|
if ndir.is_negative:
|
|
return S.One
|
|
return (arg - arg0).as_leading_term(x, logx=logx, cdir=cdir)
|
|
else:
|
|
return r
|
|
elif arg0 in (S.ComplexInfinity, S.Infinity, S.NegativeInfinity):
|
|
return AccumBounds(0, 1)
|
|
return arg.as_leading_term(x, logx=logx, cdir=cdir)
|
|
|
|
def _eval_nseries(self, x, n, logx, cdir=0):
|
|
from sympy.series.order import Order
|
|
arg = self.args[0]
|
|
arg0 = arg.subs(x, 0)
|
|
r = self.subs(x, 0)
|
|
|
|
if arg0.is_infinite:
|
|
from sympy.calculus.accumulationbounds import AccumBounds
|
|
o = Order(1, (x, 0)) if n <= 0 else AccumBounds(0, 1) + Order(x**n, (x, 0))
|
|
return o
|
|
else:
|
|
res = (arg - arg0)._eval_nseries(x, n, logx=logx, cdir=cdir)
|
|
if r.is_zero:
|
|
ndir = arg.dir(x, cdir=cdir)
|
|
res += S.One if ndir.is_negative else S.Zero
|
|
else:
|
|
res += r
|
|
return res
|
|
|
|
|
|
@dispatch(frac, Basic) # type:ignore
|
|
def _eval_is_eq(lhs, rhs): # noqa:F811
|
|
if (lhs.rewrite(floor) == rhs) or \
|
|
(lhs.rewrite(ceiling) == rhs):
|
|
return True
|
|
# Check if other < 0
|
|
if rhs.is_extended_negative:
|
|
return False
|
|
# Check if other >= 1
|
|
res = lhs._value_one_or_more(rhs)
|
|
if res is not None:
|
|
return False
|