diff options
| author | monster <[email protected]> | 2022-07-07 14:41:37 +0300 |
|---|---|---|
| committer | monster <[email protected]> | 2022-07-07 14:41:37 +0300 |
| commit | 06e5c21a835c0e923506c4ff27929f34e00761c2 (patch) | |
| tree | 75efcbc6854ef9bd476eb8bf00cc5c900da436a2 /contrib/tools/python3/src/Lib/fractions.py | |
| parent | 03f024c4412e3aa613bb543cf1660176320ba8f4 (diff) | |
fix ya.make
Diffstat (limited to 'contrib/tools/python3/src/Lib/fractions.py')
| -rw-r--r-- | contrib/tools/python3/src/Lib/fractions.py | 748 |
1 files changed, 0 insertions, 748 deletions
diff --git a/contrib/tools/python3/src/Lib/fractions.py b/contrib/tools/python3/src/Lib/fractions.py deleted file mode 100644 index 96047beb454..00000000000 --- a/contrib/tools/python3/src/Lib/fractions.py +++ /dev/null @@ -1,748 +0,0 @@ -# Originally contributed by Sjoerd Mullender. -# Significantly modified by Jeffrey Yasskin <jyasskin at gmail.com>. - -"""Fraction, infinite-precision, real numbers.""" - -from decimal import Decimal -import math -import numbers -import operator -import re -import sys - -__all__ = ['Fraction'] - - -# Constants related to the hash implementation; hash(x) is based -# on the reduction of x modulo the prime _PyHASH_MODULUS. -_PyHASH_MODULUS = sys.hash_info.modulus -# Value to be used for rationals that reduce to infinity modulo -# _PyHASH_MODULUS. -_PyHASH_INF = sys.hash_info.inf - -_RATIONAL_FORMAT = re.compile(r""" - \A\s* # optional whitespace at the start, then - (?P<sign>[-+]?) # an optional sign, then - (?=\d|\.\d) # lookahead for digit or .digit - (?P<num>\d*) # numerator (possibly empty) - (?: # followed by - (?:/(?P<denom>\d+))? # an optional denominator - | # or - (?:\.(?P<decimal>\d*))? # an optional fractional part - (?:E(?P<exp>[-+]?\d+))? # and optional exponent - ) - \s*\Z # and optional whitespace to finish -""", re.VERBOSE | re.IGNORECASE) - - -class Fraction(numbers.Rational): - """This class implements rational numbers. - - In the two-argument form of the constructor, Fraction(8, 6) will - produce a rational number equivalent to 4/3. Both arguments must - be Rational. The numerator defaults to 0 and the denominator - defaults to 1 so that Fraction(3) == 3 and Fraction() == 0. - - Fractions can also be constructed from: - - - numeric strings similar to those accepted by the - float constructor (for example, '-2.3' or '1e10') - - - strings of the form '123/456' - - - float and Decimal instances - - - other Rational instances (including integers) - - """ - - __slots__ = ('_numerator', '_denominator') - - # We're immutable, so use __new__ not __init__ - def __new__(cls, numerator=0, denominator=None, *, _normalize=True): - """Constructs a Rational. - - Takes a string like '3/2' or '1.5', another Rational instance, a - numerator/denominator pair, or a float. - - Examples - -------- - - >>> Fraction(10, -8) - Fraction(-5, 4) - >>> Fraction(Fraction(1, 7), 5) - Fraction(1, 35) - >>> Fraction(Fraction(1, 7), Fraction(2, 3)) - Fraction(3, 14) - >>> Fraction('314') - Fraction(314, 1) - >>> Fraction('-35/4') - Fraction(-35, 4) - >>> Fraction('3.1415') # conversion from numeric string - Fraction(6283, 2000) - >>> Fraction('-47e-2') # string may include a decimal exponent - Fraction(-47, 100) - >>> Fraction(1.47) # direct construction from float (exact conversion) - Fraction(6620291452234629, 4503599627370496) - >>> Fraction(2.25) - Fraction(9, 4) - >>> Fraction(Decimal('1.47')) - Fraction(147, 100) - - """ - self = super(Fraction, cls).__new__(cls) - - if denominator is None: - if type(numerator) is int: - self._numerator = numerator - self._denominator = 1 - return self - - elif isinstance(numerator, numbers.Rational): - self._numerator = numerator.numerator - self._denominator = numerator.denominator - return self - - elif isinstance(numerator, (float, Decimal)): - # Exact conversion - self._numerator, self._denominator = numerator.as_integer_ratio() - return self - - elif isinstance(numerator, str): - # Handle construction from strings. - m = _RATIONAL_FORMAT.match(numerator) - if m is None: - raise ValueError('Invalid literal for Fraction: %r' % - numerator) - numerator = int(m.group('num') or '0') - denom = m.group('denom') - if denom: - denominator = int(denom) - else: - denominator = 1 - decimal = m.group('decimal') - if decimal: - scale = 10**len(decimal) - numerator = numerator * scale + int(decimal) - denominator *= scale - exp = m.group('exp') - if exp: - exp = int(exp) - if exp >= 0: - numerator *= 10**exp - else: - denominator *= 10**-exp - if m.group('sign') == '-': - numerator = -numerator - - else: - raise TypeError("argument should be a string " - "or a Rational instance") - - elif type(numerator) is int is type(denominator): - pass # *very* normal case - - elif (isinstance(numerator, numbers.Rational) and - isinstance(denominator, numbers.Rational)): - numerator, denominator = ( - numerator.numerator * denominator.denominator, - denominator.numerator * numerator.denominator - ) - else: - raise TypeError("both arguments should be " - "Rational instances") - - if denominator == 0: - raise ZeroDivisionError('Fraction(%s, 0)' % numerator) - if _normalize: - g = math.gcd(numerator, denominator) - if denominator < 0: - g = -g - numerator //= g - denominator //= g - self._numerator = numerator - self._denominator = denominator - return self - - @classmethod - def from_float(cls, f): - """Converts a finite float to a rational number, exactly. - - Beware that Fraction.from_float(0.3) != Fraction(3, 10). - - """ - if isinstance(f, numbers.Integral): - return cls(f) - elif not isinstance(f, float): - raise TypeError("%s.from_float() only takes floats, not %r (%s)" % - (cls.__name__, f, type(f).__name__)) - return cls(*f.as_integer_ratio()) - - @classmethod - def from_decimal(cls, dec): - """Converts a finite Decimal instance to a rational number, exactly.""" - from decimal import Decimal - if isinstance(dec, numbers.Integral): - dec = Decimal(int(dec)) - elif not isinstance(dec, Decimal): - raise TypeError( - "%s.from_decimal() only takes Decimals, not %r (%s)" % - (cls.__name__, dec, type(dec).__name__)) - return cls(*dec.as_integer_ratio()) - - def as_integer_ratio(self): - """Return the integer ratio as a tuple. - - Return a tuple of two integers, whose ratio is equal to the - Fraction and with a positive denominator. - """ - return (self._numerator, self._denominator) - - def limit_denominator(self, max_denominator=1000000): - """Closest Fraction to self with denominator at most max_denominator. - - >>> Fraction('3.141592653589793').limit_denominator(10) - Fraction(22, 7) - >>> Fraction('3.141592653589793').limit_denominator(100) - Fraction(311, 99) - >>> Fraction(4321, 8765).limit_denominator(10000) - Fraction(4321, 8765) - - """ - # Algorithm notes: For any real number x, define a *best upper - # approximation* to x to be a rational number p/q such that: - # - # (1) p/q >= x, and - # (2) if p/q > r/s >= x then s > q, for any rational r/s. - # - # Define *best lower approximation* similarly. Then it can be - # proved that a rational number is a best upper or lower - # approximation to x if, and only if, it is a convergent or - # semiconvergent of the (unique shortest) continued fraction - # associated to x. - # - # To find a best rational approximation with denominator <= M, - # we find the best upper and lower approximations with - # denominator <= M and take whichever of these is closer to x. - # In the event of a tie, the bound with smaller denominator is - # chosen. If both denominators are equal (which can happen - # only when max_denominator == 1 and self is midway between - # two integers) the lower bound---i.e., the floor of self, is - # taken. - - if max_denominator < 1: - raise ValueError("max_denominator should be at least 1") - if self._denominator <= max_denominator: - return Fraction(self) - - p0, q0, p1, q1 = 0, 1, 1, 0 - n, d = self._numerator, self._denominator - while True: - a = n//d - q2 = q0+a*q1 - if q2 > max_denominator: - break - p0, q0, p1, q1 = p1, q1, p0+a*p1, q2 - n, d = d, n-a*d - - k = (max_denominator-q0)//q1 - bound1 = Fraction(p0+k*p1, q0+k*q1) - bound2 = Fraction(p1, q1) - if abs(bound2 - self) <= abs(bound1-self): - return bound2 - else: - return bound1 - - @property - def numerator(a): - return a._numerator - - @property - def denominator(a): - return a._denominator - - def __repr__(self): - """repr(self)""" - return '%s(%s, %s)' % (self.__class__.__name__, - self._numerator, self._denominator) - - def __str__(self): - """str(self)""" - if self._denominator == 1: - return str(self._numerator) - else: - return '%s/%s' % (self._numerator, self._denominator) - - def _operator_fallbacks(monomorphic_operator, fallback_operator): - """Generates forward and reverse operators given a purely-rational - operator and a function from the operator module. - - Use this like: - __op__, __rop__ = _operator_fallbacks(just_rational_op, operator.op) - - In general, we want to implement the arithmetic operations so - that mixed-mode operations either call an implementation whose - author knew about the types of both arguments, or convert both - to the nearest built in type and do the operation there. In - Fraction, that means that we define __add__ and __radd__ as: - - def __add__(self, other): - # Both types have numerators/denominator attributes, - # so do the operation directly - if isinstance(other, (int, Fraction)): - return Fraction(self.numerator * other.denominator + - other.numerator * self.denominator, - self.denominator * other.denominator) - # float and complex don't have those operations, but we - # know about those types, so special case them. - elif isinstance(other, float): - return float(self) + other - elif isinstance(other, complex): - return complex(self) + other - # Let the other type take over. - return NotImplemented - - def __radd__(self, other): - # radd handles more types than add because there's - # nothing left to fall back to. - if isinstance(other, numbers.Rational): - return Fraction(self.numerator * other.denominator + - other.numerator * self.denominator, - self.denominator * other.denominator) - elif isinstance(other, Real): - return float(other) + float(self) - elif isinstance(other, Complex): - return complex(other) + complex(self) - return NotImplemented - - - There are 5 different cases for a mixed-type addition on - Fraction. I'll refer to all of the above code that doesn't - refer to Fraction, float, or complex as "boilerplate". 'r' - will be an instance of Fraction, which is a subtype of - Rational (r : Fraction <: Rational), and b : B <: - Complex. The first three involve 'r + b': - - 1. If B <: Fraction, int, float, or complex, we handle - that specially, and all is well. - 2. If Fraction falls back to the boilerplate code, and it - were to return a value from __add__, we'd miss the - possibility that B defines a more intelligent __radd__, - so the boilerplate should return NotImplemented from - __add__. In particular, we don't handle Rational - here, even though we could get an exact answer, in case - the other type wants to do something special. - 3. If B <: Fraction, Python tries B.__radd__ before - Fraction.__add__. This is ok, because it was - implemented with knowledge of Fraction, so it can - handle those instances before delegating to Real or - Complex. - - The next two situations describe 'b + r'. We assume that b - didn't know about Fraction in its implementation, and that it - uses similar boilerplate code: - - 4. If B <: Rational, then __radd_ converts both to the - builtin rational type (hey look, that's us) and - proceeds. - 5. Otherwise, __radd__ tries to find the nearest common - base ABC, and fall back to its builtin type. Since this - class doesn't subclass a concrete type, there's no - implementation to fall back to, so we need to try as - hard as possible to return an actual value, or the user - will get a TypeError. - - """ - def forward(a, b): - if isinstance(b, (int, Fraction)): - return monomorphic_operator(a, b) - elif isinstance(b, float): - return fallback_operator(float(a), b) - elif isinstance(b, complex): - return fallback_operator(complex(a), b) - else: - return NotImplemented - forward.__name__ = '__' + fallback_operator.__name__ + '__' - forward.__doc__ = monomorphic_operator.__doc__ - - def reverse(b, a): - if isinstance(a, numbers.Rational): - # Includes ints. - return monomorphic_operator(a, b) - elif isinstance(a, numbers.Real): - return fallback_operator(float(a), float(b)) - elif isinstance(a, numbers.Complex): - return fallback_operator(complex(a), complex(b)) - else: - return NotImplemented - reverse.__name__ = '__r' + fallback_operator.__name__ + '__' - reverse.__doc__ = monomorphic_operator.__doc__ - - return forward, reverse - - # Rational arithmetic algorithms: Knuth, TAOCP, Volume 2, 4.5.1. - # - # Assume input fractions a and b are normalized. - # - # 1) Consider addition/subtraction. - # - # Let g = gcd(da, db). Then - # - # na nb na*db ± nb*da - # a ± b == -- ± -- == ------------- == - # da db da*db - # - # na*(db//g) ± nb*(da//g) t - # == ----------------------- == - - # (da*db)//g d - # - # Now, if g > 1, we're working with smaller integers. - # - # Note, that t, (da//g) and (db//g) are pairwise coprime. - # - # Indeed, (da//g) and (db//g) share no common factors (they were - # removed) and da is coprime with na (since input fractions are - # normalized), hence (da//g) and na are coprime. By symmetry, - # (db//g) and nb are coprime too. Then, - # - # gcd(t, da//g) == gcd(na*(db//g), da//g) == 1 - # gcd(t, db//g) == gcd(nb*(da//g), db//g) == 1 - # - # Above allows us optimize reduction of the result to lowest - # terms. Indeed, - # - # g2 = gcd(t, d) == gcd(t, (da//g)*(db//g)*g) == gcd(t, g) - # - # t//g2 t//g2 - # a ± b == ----------------------- == ---------------- - # (da//g)*(db//g)*(g//g2) (da//g)*(db//g2) - # - # is a normalized fraction. This is useful because the unnormalized - # denominator d could be much larger than g. - # - # We should special-case g == 1 (and g2 == 1), since 60.8% of - # randomly-chosen integers are coprime: - # https://en.wikipedia.org/wiki/Coprime_integers#Probability_of_coprimality - # Note, that g2 == 1 always for fractions, obtained from floats: here - # g is a power of 2 and the unnormalized numerator t is an odd integer. - # - # 2) Consider multiplication - # - # Let g1 = gcd(na, db) and g2 = gcd(nb, da), then - # - # na*nb na*nb (na//g1)*(nb//g2) - # a*b == ----- == ----- == ----------------- - # da*db db*da (db//g1)*(da//g2) - # - # Note, that after divisions we're multiplying smaller integers. - # - # Also, the resulting fraction is normalized, because each of - # two factors in the numerator is coprime to each of the two factors - # in the denominator. - # - # Indeed, pick (na//g1). It's coprime with (da//g2), because input - # fractions are normalized. It's also coprime with (db//g1), because - # common factors are removed by g1 == gcd(na, db). - # - # As for addition/subtraction, we should special-case g1 == 1 - # and g2 == 1 for same reason. That happens also for multiplying - # rationals, obtained from floats. - - def _add(a, b): - """a + b""" - na, da = a.numerator, a.denominator - nb, db = b.numerator, b.denominator - g = math.gcd(da, db) - if g == 1: - return Fraction(na * db + da * nb, da * db, _normalize=False) - s = da // g - t = na * (db // g) + nb * s - g2 = math.gcd(t, g) - if g2 == 1: - return Fraction(t, s * db, _normalize=False) - return Fraction(t // g2, s * (db // g2), _normalize=False) - - __add__, __radd__ = _operator_fallbacks(_add, operator.add) - - def _sub(a, b): - """a - b""" - na, da = a.numerator, a.denominator - nb, db = b.numerator, b.denominator - g = math.gcd(da, db) - if g == 1: - return Fraction(na * db - da * nb, da * db, _normalize=False) - s = da // g - t = na * (db // g) - nb * s - g2 = math.gcd(t, g) - if g2 == 1: - return Fraction(t, s * db, _normalize=False) - return Fraction(t // g2, s * (db // g2), _normalize=False) - - __sub__, __rsub__ = _operator_fallbacks(_sub, operator.sub) - - def _mul(a, b): - """a * b""" - na, da = a.numerator, a.denominator - nb, db = b.numerator, b.denominator - g1 = math.gcd(na, db) - if g1 > 1: - na //= g1 - db //= g1 - g2 = math.gcd(nb, da) - if g2 > 1: - nb //= g2 - da //= g2 - return Fraction(na * nb, db * da, _normalize=False) - - __mul__, __rmul__ = _operator_fallbacks(_mul, operator.mul) - - def _div(a, b): - """a / b""" - # Same as _mul(), with inversed b. - na, da = a.numerator, a.denominator - nb, db = b.numerator, b.denominator - g1 = math.gcd(na, nb) - if g1 > 1: - na //= g1 - nb //= g1 - g2 = math.gcd(db, da) - if g2 > 1: - da //= g2 - db //= g2 - n, d = na * db, nb * da - if d < 0: - n, d = -n, -d - return Fraction(n, d, _normalize=False) - - __truediv__, __rtruediv__ = _operator_fallbacks(_div, operator.truediv) - - def _floordiv(a, b): - """a // b""" - return (a.numerator * b.denominator) // (a.denominator * b.numerator) - - __floordiv__, __rfloordiv__ = _operator_fallbacks(_floordiv, operator.floordiv) - - def _divmod(a, b): - """(a // b, a % b)""" - da, db = a.denominator, b.denominator - div, n_mod = divmod(a.numerator * db, da * b.numerator) - return div, Fraction(n_mod, da * db) - - __divmod__, __rdivmod__ = _operator_fallbacks(_divmod, divmod) - - def _mod(a, b): - """a % b""" - da, db = a.denominator, b.denominator - return Fraction((a.numerator * db) % (b.numerator * da), da * db) - - __mod__, __rmod__ = _operator_fallbacks(_mod, operator.mod) - - def __pow__(a, b): - """a ** b - - If b is not an integer, the result will be a float or complex - since roots are generally irrational. If b is an integer, the - result will be rational. - - """ - if isinstance(b, numbers.Rational): - if b.denominator == 1: - power = b.numerator - if power >= 0: - return Fraction(a._numerator ** power, - a._denominator ** power, - _normalize=False) - elif a._numerator >= 0: - return Fraction(a._denominator ** -power, - a._numerator ** -power, - _normalize=False) - else: - return Fraction((-a._denominator) ** -power, - (-a._numerator) ** -power, - _normalize=False) - else: - # A fractional power will generally produce an - # irrational number. - return float(a) ** float(b) - else: - return float(a) ** b - - def __rpow__(b, a): - """a ** b""" - if b._denominator == 1 and b._numerator >= 0: - # If a is an int, keep it that way if possible. - return a ** b._numerator - - if isinstance(a, numbers.Rational): - return Fraction(a.numerator, a.denominator) ** b - - if b._denominator == 1: - return a ** b._numerator - - return a ** float(b) - - def __pos__(a): - """+a: Coerces a subclass instance to Fraction""" - return Fraction(a._numerator, a._denominator, _normalize=False) - - def __neg__(a): - """-a""" - return Fraction(-a._numerator, a._denominator, _normalize=False) - - def __abs__(a): - """abs(a)""" - return Fraction(abs(a._numerator), a._denominator, _normalize=False) - - def __trunc__(a): - """trunc(a)""" - if a._numerator < 0: - return -(-a._numerator // a._denominator) - else: - return a._numerator // a._denominator - - def __floor__(a): - """math.floor(a)""" - return a.numerator // a.denominator - - def __ceil__(a): - """math.ceil(a)""" - # The negations cleverly convince floordiv to return the ceiling. - return -(-a.numerator // a.denominator) - - def __round__(self, ndigits=None): - """round(self, ndigits) - - Rounds half toward even. - """ - if ndigits is None: - floor, remainder = divmod(self.numerator, self.denominator) - if remainder * 2 < self.denominator: - return floor - elif remainder * 2 > self.denominator: - return floor + 1 - # Deal with the half case: - elif floor % 2 == 0: - return floor - else: - return floor + 1 - shift = 10**abs(ndigits) - # See _operator_fallbacks.forward to check that the results of - # these operations will always be Fraction and therefore have - # round(). - if ndigits > 0: - return Fraction(round(self * shift), shift) - else: - return Fraction(round(self / shift) * shift) - - def __hash__(self): - """hash(self)""" - - # To make sure that the hash of a Fraction agrees with the hash - # of a numerically equal integer, float or Decimal instance, we - # follow the rules for numeric hashes outlined in the - # documentation. (See library docs, 'Built-in Types'). - - try: - dinv = pow(self._denominator, -1, _PyHASH_MODULUS) - except ValueError: - # ValueError means there is no modular inverse. - hash_ = _PyHASH_INF - else: - # The general algorithm now specifies that the absolute value of - # the hash is - # (|N| * dinv) % P - # where N is self._numerator and P is _PyHASH_MODULUS. That's - # optimized here in two ways: first, for a non-negative int i, - # hash(i) == i % P, but the int hash implementation doesn't need - # to divide, and is faster than doing % P explicitly. So we do - # hash(|N| * dinv) - # instead. Second, N is unbounded, so its product with dinv may - # be arbitrarily expensive to compute. The final answer is the - # same if we use the bounded |N| % P instead, which can again - # be done with an int hash() call. If 0 <= i < P, hash(i) == i, - # so this nested hash() call wastes a bit of time making a - # redundant copy when |N| < P, but can save an arbitrarily large - # amount of computation for large |N|. - hash_ = hash(hash(abs(self._numerator)) * dinv) - result = hash_ if self._numerator >= 0 else -hash_ - return -2 if result == -1 else result - - def __eq__(a, b): - """a == b""" - if type(b) is int: - return a._numerator == b and a._denominator == 1 - if isinstance(b, numbers.Rational): - return (a._numerator == b.numerator and - a._denominator == b.denominator) - if isinstance(b, numbers.Complex) and b.imag == 0: - b = b.real - if isinstance(b, float): - if math.isnan(b) or math.isinf(b): - # comparisons with an infinity or nan should behave in - # the same way for any finite a, so treat a as zero. - return 0.0 == b - else: - return a == a.from_float(b) - else: - # Since a doesn't know how to compare with b, let's give b - # a chance to compare itself with a. - return NotImplemented - - def _richcmp(self, other, op): - """Helper for comparison operators, for internal use only. - - Implement comparison between a Rational instance `self`, and - either another Rational instance or a float `other`. If - `other` is not a Rational instance or a float, return - NotImplemented. `op` should be one of the six standard - comparison operators. - - """ - # convert other to a Rational instance where reasonable. - if isinstance(other, numbers.Rational): - return op(self._numerator * other.denominator, - self._denominator * other.numerator) - if isinstance(other, float): - if math.isnan(other) or math.isinf(other): - return op(0.0, other) - else: - return op(self, self.from_float(other)) - else: - return NotImplemented - - def __lt__(a, b): - """a < b""" - return a._richcmp(b, operator.lt) - - def __gt__(a, b): - """a > b""" - return a._richcmp(b, operator.gt) - - def __le__(a, b): - """a <= b""" - return a._richcmp(b, operator.le) - - def __ge__(a, b): - """a >= b""" - return a._richcmp(b, operator.ge) - - def __bool__(a): - """a != 0""" - # bpo-39274: Use bool() because (a._numerator != 0) can return an - # object which is not a bool. - return bool(a._numerator) - - # support for pickling, copy, and deepcopy - - def __reduce__(self): - return (self.__class__, (str(self),)) - - def __copy__(self): - if type(self) == Fraction: - return self # I'm immutable; therefore I am my own clone - return self.__class__(self._numerator, self._denominator) - - def __deepcopy__(self, memo): - if type(self) == Fraction: - return self # My components are also immutable - return self.__class__(self._numerator, self._denominator) |
