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- __builtin__.object
-
- Context
- Decimal
- exceptions.ArithmeticError(exceptions.StandardError)
-
- DecimalException
-
- Clamped
- DivisionByZero(DecimalException, exceptions.ZeroDivisionError)
- Inexact
-
- Overflow(Inexact, Rounded)
- Underflow(Inexact, Rounded, Subnormal)
- InvalidOperation
- Rounded
- Subnormal
class Context(__builtin__.object) |
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Contains the context for a Decimal instance.
Contains:
prec - precision (for use in rounding, division, square roots..)
rounding - rounding type (how you round)
traps - If traps[exception] = 1, then the exception is
raised when it is caused. Otherwise, a value is
substituted in.
flags - When an exception is caused, flags[exception] is set.
(Whether or not the trap_enabler is set)
Should be reset by user of Decimal instance.
Emin - Minimum exponent
Emax - Maximum exponent
capitals - If 1, 1*10^1 is printed as 1E+1.
If 0, printed as 1e1
_clamp - If 1, change exponents if too high (Default 0)
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Methods defined here:
- Etiny(self)
- Returns Etiny (= Emin - prec + 1)
- Etop(self)
- Returns maximum exponent (= Emax - prec + 1)
- __copy__ = copy(self)
- __init__(self, prec=None, rounding=None, traps=None, flags=None, Emin=None, Emax=None, capitals=None, _clamp=0, _ignored_flags=None)
- __repr__(self)
- Show the current context.
- abs(self, a)
- Returns the absolute value of the operand.
If the operand is negative, the result is the same as using the minus
operation on the operand. Otherwise, the result is the same as using
the plus operation on the operand.
>>> ExtendedContext.abs(Decimal('2.1'))
Decimal('2.1')
>>> ExtendedContext.abs(Decimal('-100'))
Decimal('100')
>>> ExtendedContext.abs(Decimal('101.5'))
Decimal('101.5')
>>> ExtendedContext.abs(Decimal('-101.5'))
Decimal('101.5')
>>> ExtendedContext.abs(-1)
Decimal('1')
- add(self, a, b)
- Return the sum of the two operands.
>>> ExtendedContext.add(Decimal('12'), Decimal('7.00'))
Decimal('19.00')
>>> ExtendedContext.add(Decimal('1E+2'), Decimal('1.01E+4'))
Decimal('1.02E+4')
>>> ExtendedContext.add(1, Decimal(2))
Decimal('3')
>>> ExtendedContext.add(Decimal(8), 5)
Decimal('13')
>>> ExtendedContext.add(5, 5)
Decimal('10')
- canonical(self, a)
- Returns the same Decimal object.
As we do not have different encodings for the same number, the
received object already is in its canonical form.
>>> ExtendedContext.canonical(Decimal('2.50'))
Decimal('2.50')
- clear_flags(self)
- Reset all flags to zero
- compare(self, a, b)
- Compares values numerically.
If the signs of the operands differ, a value representing each operand
('-1' if the operand is less than zero, '0' if the operand is zero or
negative zero, or '1' if the operand is greater than zero) is used in
place of that operand for the comparison instead of the actual
operand.
The comparison is then effected by subtracting the second operand from
the first and then returning a value according to the result of the
subtraction: '-1' if the result is less than zero, '0' if the result is
zero or negative zero, or '1' if the result is greater than zero.
>>> ExtendedContext.compare(Decimal('2.1'), Decimal('3'))
Decimal('-1')
>>> ExtendedContext.compare(Decimal('2.1'), Decimal('2.1'))
Decimal('0')
>>> ExtendedContext.compare(Decimal('2.1'), Decimal('2.10'))
Decimal('0')
>>> ExtendedContext.compare(Decimal('3'), Decimal('2.1'))
Decimal('1')
>>> ExtendedContext.compare(Decimal('2.1'), Decimal('-3'))
Decimal('1')
>>> ExtendedContext.compare(Decimal('-3'), Decimal('2.1'))
Decimal('-1')
>>> ExtendedContext.compare(1, 2)
Decimal('-1')
>>> ExtendedContext.compare(Decimal(1), 2)
Decimal('-1')
>>> ExtendedContext.compare(1, Decimal(2))
Decimal('-1')
- compare_signal(self, a, b)
- Compares the values of the two operands numerically.
It's pretty much like compare(), but all NaNs signal, with signaling
NaNs taking precedence over quiet NaNs.
>>> c = ExtendedContext
>>> c.compare_signal(Decimal('2.1'), Decimal('3'))
Decimal('-1')
>>> c.compare_signal(Decimal('2.1'), Decimal('2.1'))
Decimal('0')
>>> c.flags[InvalidOperation] = 0
>>> print c.flags[InvalidOperation]
0
>>> c.compare_signal(Decimal('NaN'), Decimal('2.1'))
Decimal('NaN')
>>> print c.flags[InvalidOperation]
1
>>> c.flags[InvalidOperation] = 0
>>> print c.flags[InvalidOperation]
0
>>> c.compare_signal(Decimal('sNaN'), Decimal('2.1'))
Decimal('NaN')
>>> print c.flags[InvalidOperation]
1
>>> c.compare_signal(-1, 2)
Decimal('-1')
>>> c.compare_signal(Decimal(-1), 2)
Decimal('-1')
>>> c.compare_signal(-1, Decimal(2))
Decimal('-1')
- compare_total(self, a, b)
- Compares two operands using their abstract representation.
This is not like the standard compare, which use their numerical
value. Note that a total ordering is defined for all possible abstract
representations.
>>> ExtendedContext.compare_total(Decimal('12.73'), Decimal('127.9'))
Decimal('-1')
>>> ExtendedContext.compare_total(Decimal('-127'), Decimal('12'))
Decimal('-1')
>>> ExtendedContext.compare_total(Decimal('12.30'), Decimal('12.3'))
Decimal('-1')
>>> ExtendedContext.compare_total(Decimal('12.30'), Decimal('12.30'))
Decimal('0')
>>> ExtendedContext.compare_total(Decimal('12.3'), Decimal('12.300'))
Decimal('1')
>>> ExtendedContext.compare_total(Decimal('12.3'), Decimal('NaN'))
Decimal('-1')
>>> ExtendedContext.compare_total(1, 2)
Decimal('-1')
>>> ExtendedContext.compare_total(Decimal(1), 2)
Decimal('-1')
>>> ExtendedContext.compare_total(1, Decimal(2))
Decimal('-1')
- compare_total_mag(self, a, b)
- Compares two operands using their abstract representation ignoring sign.
Like compare_total, but with operand's sign ignored and assumed to be 0.
- copy(self)
- Returns a deep copy from self.
- copy_abs(self, a)
- Returns a copy of the operand with the sign set to 0.
>>> ExtendedContext.copy_abs(Decimal('2.1'))
Decimal('2.1')
>>> ExtendedContext.copy_abs(Decimal('-100'))
Decimal('100')
>>> ExtendedContext.copy_abs(-1)
Decimal('1')
- copy_decimal(self, a)
- Returns a copy of the decimal object.
>>> ExtendedContext.copy_decimal(Decimal('2.1'))
Decimal('2.1')
>>> ExtendedContext.copy_decimal(Decimal('-1.00'))
Decimal('-1.00')
>>> ExtendedContext.copy_decimal(1)
Decimal('1')
- copy_negate(self, a)
- Returns a copy of the operand with the sign inverted.
>>> ExtendedContext.copy_negate(Decimal('101.5'))
Decimal('-101.5')
>>> ExtendedContext.copy_negate(Decimal('-101.5'))
Decimal('101.5')
>>> ExtendedContext.copy_negate(1)
Decimal('-1')
- copy_sign(self, a, b)
- Copies the second operand's sign to the first one.
In detail, it returns a copy of the first operand with the sign
equal to the sign of the second operand.
>>> ExtendedContext.copy_sign(Decimal( '1.50'), Decimal('7.33'))
Decimal('1.50')
>>> ExtendedContext.copy_sign(Decimal('-1.50'), Decimal('7.33'))
Decimal('1.50')
>>> ExtendedContext.copy_sign(Decimal( '1.50'), Decimal('-7.33'))
Decimal('-1.50')
>>> ExtendedContext.copy_sign(Decimal('-1.50'), Decimal('-7.33'))
Decimal('-1.50')
>>> ExtendedContext.copy_sign(1, -2)
Decimal('-1')
>>> ExtendedContext.copy_sign(Decimal(1), -2)
Decimal('-1')
>>> ExtendedContext.copy_sign(1, Decimal(-2))
Decimal('-1')
- create_decimal(self, num='0')
- Creates a new Decimal instance but using self as context.
This method implements the to-number operation of the
IBM Decimal specification.
- create_decimal_from_float(self, f)
- Creates a new Decimal instance from a float but rounding using self
as the context.
>>> context = Context(prec=5, rounding=ROUND_DOWN)
>>> context.create_decimal_from_float(3.1415926535897932)
Decimal('3.1415')
>>> context = Context(prec=5, traps=[Inexact])
>>> context.create_decimal_from_float(3.1415926535897932)
Traceback (most recent call last):
...
Inexact: None
- divide(self, a, b)
- Decimal division in a specified context.
>>> ExtendedContext.divide(Decimal('1'), Decimal('3'))
Decimal('0.333333333')
>>> ExtendedContext.divide(Decimal('2'), Decimal('3'))
Decimal('0.666666667')
>>> ExtendedContext.divide(Decimal('5'), Decimal('2'))
Decimal('2.5')
>>> ExtendedContext.divide(Decimal('1'), Decimal('10'))
Decimal('0.1')
>>> ExtendedContext.divide(Decimal('12'), Decimal('12'))
Decimal('1')
>>> ExtendedContext.divide(Decimal('8.00'), Decimal('2'))
Decimal('4.00')
>>> ExtendedContext.divide(Decimal('2.400'), Decimal('2.0'))
Decimal('1.20')
>>> ExtendedContext.divide(Decimal('1000'), Decimal('100'))
Decimal('10')
>>> ExtendedContext.divide(Decimal('1000'), Decimal('1'))
Decimal('1000')
>>> ExtendedContext.divide(Decimal('2.40E+6'), Decimal('2'))
Decimal('1.20E+6')
>>> ExtendedContext.divide(5, 5)
Decimal('1')
>>> ExtendedContext.divide(Decimal(5), 5)
Decimal('1')
>>> ExtendedContext.divide(5, Decimal(5))
Decimal('1')
- divide_int(self, a, b)
- Divides two numbers and returns the integer part of the result.
>>> ExtendedContext.divide_int(Decimal('2'), Decimal('3'))
Decimal('0')
>>> ExtendedContext.divide_int(Decimal('10'), Decimal('3'))
Decimal('3')
>>> ExtendedContext.divide_int(Decimal('1'), Decimal('0.3'))
Decimal('3')
>>> ExtendedContext.divide_int(10, 3)
Decimal('3')
>>> ExtendedContext.divide_int(Decimal(10), 3)
Decimal('3')
>>> ExtendedContext.divide_int(10, Decimal(3))
Decimal('3')
- divmod(self, a, b)
- Return (a // b, a % b).
>>> ExtendedContext.divmod(Decimal(8), Decimal(3))
(Decimal('2'), Decimal('2'))
>>> ExtendedContext.divmod(Decimal(8), Decimal(4))
(Decimal('2'), Decimal('0'))
>>> ExtendedContext.divmod(8, 4)
(Decimal('2'), Decimal('0'))
>>> ExtendedContext.divmod(Decimal(8), 4)
(Decimal('2'), Decimal('0'))
>>> ExtendedContext.divmod(8, Decimal(4))
(Decimal('2'), Decimal('0'))
- exp(self, a)
- Returns e ** a.
>>> c = ExtendedContext.copy()
>>> c.Emin = -999
>>> c.Emax = 999
>>> c.exp(Decimal('-Infinity'))
Decimal('0')
>>> c.exp(Decimal('-1'))
Decimal('0.367879441')
>>> c.exp(Decimal('0'))
Decimal('1')
>>> c.exp(Decimal('1'))
Decimal('2.71828183')
>>> c.exp(Decimal('0.693147181'))
Decimal('2.00000000')
>>> c.exp(Decimal('+Infinity'))
Decimal('Infinity')
>>> c.exp(10)
Decimal('22026.4658')
- fma(self, a, b, c)
- Returns a multiplied by b, plus c.
The first two operands are multiplied together, using multiply,
the third operand is then added to the result of that
multiplication, using add, all with only one final rounding.
>>> ExtendedContext.fma(Decimal('3'), Decimal('5'), Decimal('7'))
Decimal('22')
>>> ExtendedContext.fma(Decimal('3'), Decimal('-5'), Decimal('7'))
Decimal('-8')
>>> ExtendedContext.fma(Decimal('888565290'), Decimal('1557.96930'), Decimal('-86087.7578'))
Decimal('1.38435736E+12')
>>> ExtendedContext.fma(1, 3, 4)
Decimal('7')
>>> ExtendedContext.fma(1, Decimal(3), 4)
Decimal('7')
>>> ExtendedContext.fma(1, 3, Decimal(4))
Decimal('7')
- is_canonical(self, a)
- Return True if the operand is canonical; otherwise return False.
Currently, the encoding of a Decimal instance is always
canonical, so this method returns True for any Decimal.
>>> ExtendedContext.is_canonical(Decimal('2.50'))
True
- is_finite(self, a)
- Return True if the operand is finite; otherwise return False.
A Decimal instance is considered finite if it is neither
infinite nor a NaN.
>>> ExtendedContext.is_finite(Decimal('2.50'))
True
>>> ExtendedContext.is_finite(Decimal('-0.3'))
True
>>> ExtendedContext.is_finite(Decimal('0'))
True
>>> ExtendedContext.is_finite(Decimal('Inf'))
False
>>> ExtendedContext.is_finite(Decimal('NaN'))
False
>>> ExtendedContext.is_finite(1)
True
- is_infinite(self, a)
- Return True if the operand is infinite; otherwise return False.
>>> ExtendedContext.is_infinite(Decimal('2.50'))
False
>>> ExtendedContext.is_infinite(Decimal('-Inf'))
True
>>> ExtendedContext.is_infinite(Decimal('NaN'))
False
>>> ExtendedContext.is_infinite(1)
False
- is_nan(self, a)
- Return True if the operand is a qNaN or sNaN;
otherwise return False.
>>> ExtendedContext.is_nan(Decimal('2.50'))
False
>>> ExtendedContext.is_nan(Decimal('NaN'))
True
>>> ExtendedContext.is_nan(Decimal('-sNaN'))
True
>>> ExtendedContext.is_nan(1)
False
- is_normal(self, a)
- Return True if the operand is a normal number;
otherwise return False.
>>> c = ExtendedContext.copy()
>>> c.Emin = -999
>>> c.Emax = 999
>>> c.is_normal(Decimal('2.50'))
True
>>> c.is_normal(Decimal('0.1E-999'))
False
>>> c.is_normal(Decimal('0.00'))
False
>>> c.is_normal(Decimal('-Inf'))
False
>>> c.is_normal(Decimal('NaN'))
False
>>> c.is_normal(1)
True
- is_qnan(self, a)
- Return True if the operand is a quiet NaN; otherwise return False.
>>> ExtendedContext.is_qnan(Decimal('2.50'))
False
>>> ExtendedContext.is_qnan(Decimal('NaN'))
True
>>> ExtendedContext.is_qnan(Decimal('sNaN'))
False
>>> ExtendedContext.is_qnan(1)
False
- is_signed(self, a)
- Return True if the operand is negative; otherwise return False.
>>> ExtendedContext.is_signed(Decimal('2.50'))
False
>>> ExtendedContext.is_signed(Decimal('-12'))
True
>>> ExtendedContext.is_signed(Decimal('-0'))
True
>>> ExtendedContext.is_signed(8)
False
>>> ExtendedContext.is_signed(-8)
True
- is_snan(self, a)
- Return True if the operand is a signaling NaN;
otherwise return False.
>>> ExtendedContext.is_snan(Decimal('2.50'))
False
>>> ExtendedContext.is_snan(Decimal('NaN'))
False
>>> ExtendedContext.is_snan(Decimal('sNaN'))
True
>>> ExtendedContext.is_snan(1)
False
- is_subnormal(self, a)
- Return True if the operand is subnormal; otherwise return False.
>>> c = ExtendedContext.copy()
>>> c.Emin = -999
>>> c.Emax = 999
>>> c.is_subnormal(Decimal('2.50'))
False
>>> c.is_subnormal(Decimal('0.1E-999'))
True
>>> c.is_subnormal(Decimal('0.00'))
False
>>> c.is_subnormal(Decimal('-Inf'))
False
>>> c.is_subnormal(Decimal('NaN'))
False
>>> c.is_subnormal(1)
False
- is_zero(self, a)
- Return True if the operand is a zero; otherwise return False.
>>> ExtendedContext.is_zero(Decimal('0'))
True
>>> ExtendedContext.is_zero(Decimal('2.50'))
False
>>> ExtendedContext.is_zero(Decimal('-0E+2'))
True
>>> ExtendedContext.is_zero(1)
False
>>> ExtendedContext.is_zero(0)
True
- ln(self, a)
- Returns the natural (base e) logarithm of the operand.
>>> c = ExtendedContext.copy()
>>> c.Emin = -999
>>> c.Emax = 999
>>> c.ln(Decimal('0'))
Decimal('-Infinity')
>>> c.ln(Decimal('1.000'))
Decimal('0')
>>> c.ln(Decimal('2.71828183'))
Decimal('1.00000000')
>>> c.ln(Decimal('10'))
Decimal('2.30258509')
>>> c.ln(Decimal('+Infinity'))
Decimal('Infinity')
>>> c.ln(1)
Decimal('0')
- log10(self, a)
- Returns the base 10 logarithm of the operand.
>>> c = ExtendedContext.copy()
>>> c.Emin = -999
>>> c.Emax = 999
>>> c.log10(Decimal('0'))
Decimal('-Infinity')
>>> c.log10(Decimal('0.001'))
Decimal('-3')
>>> c.log10(Decimal('1.000'))
Decimal('0')
>>> c.log10(Decimal('2'))
Decimal('0.301029996')
>>> c.log10(Decimal('10'))
Decimal('1')
>>> c.log10(Decimal('70'))
Decimal('1.84509804')
>>> c.log10(Decimal('+Infinity'))
Decimal('Infinity')
>>> c.log10(0)
Decimal('-Infinity')
>>> c.log10(1)
Decimal('0')
- logb(self, a)
- Returns the exponent of the magnitude of the operand's MSD.
The result is the integer which is the exponent of the magnitude
of the most significant digit of the operand (as though the
operand were truncated to a single digit while maintaining the
value of that digit and without limiting the resulting exponent).
>>> ExtendedContext.logb(Decimal('250'))
Decimal('2')
>>> ExtendedContext.logb(Decimal('2.50'))
Decimal('0')
>>> ExtendedContext.logb(Decimal('0.03'))
Decimal('-2')
>>> ExtendedContext.logb(Decimal('0'))
Decimal('-Infinity')
>>> ExtendedContext.logb(1)
Decimal('0')
>>> ExtendedContext.logb(10)
Decimal('1')
>>> ExtendedContext.logb(100)
Decimal('2')
- logical_and(self, a, b)
- Applies the logical operation 'and' between each operand's digits.
The operands must be both logical numbers.
>>> ExtendedContext.logical_and(Decimal('0'), Decimal('0'))
Decimal('0')
>>> ExtendedContext.logical_and(Decimal('0'), Decimal('1'))
Decimal('0')
>>> ExtendedContext.logical_and(Decimal('1'), Decimal('0'))
Decimal('0')
>>> ExtendedContext.logical_and(Decimal('1'), Decimal('1'))
Decimal('1')
>>> ExtendedContext.logical_and(Decimal('1100'), Decimal('1010'))
Decimal('1000')
>>> ExtendedContext.logical_and(Decimal('1111'), Decimal('10'))
Decimal('10')
>>> ExtendedContext.logical_and(110, 1101)
Decimal('100')
>>> ExtendedContext.logical_and(Decimal(110), 1101)
Decimal('100')
>>> ExtendedContext.logical_and(110, Decimal(1101))
Decimal('100')
- logical_invert(self, a)
- Invert all the digits in the operand.
The operand must be a logical number.
>>> ExtendedContext.logical_invert(Decimal('0'))
Decimal('111111111')
>>> ExtendedContext.logical_invert(Decimal('1'))
Decimal('111111110')
>>> ExtendedContext.logical_invert(Decimal('111111111'))
Decimal('0')
>>> ExtendedContext.logical_invert(Decimal('101010101'))
Decimal('10101010')
>>> ExtendedContext.logical_invert(1101)
Decimal('111110010')
- logical_or(self, a, b)
- Applies the logical operation 'or' between each operand's digits.
The operands must be both logical numbers.
>>> ExtendedContext.logical_or(Decimal('0'), Decimal('0'))
Decimal('0')
>>> ExtendedContext.logical_or(Decimal('0'), Decimal('1'))
Decimal('1')
>>> ExtendedContext.logical_or(Decimal('1'), Decimal('0'))
Decimal('1')
>>> ExtendedContext.logical_or(Decimal('1'), Decimal('1'))
Decimal('1')
>>> ExtendedContext.logical_or(Decimal('1100'), Decimal('1010'))
Decimal('1110')
>>> ExtendedContext.logical_or(Decimal('1110'), Decimal('10'))
Decimal('1110')
>>> ExtendedContext.logical_or(110, 1101)
Decimal('1111')
>>> ExtendedContext.logical_or(Decimal(110), 1101)
Decimal('1111')
>>> ExtendedContext.logical_or(110, Decimal(1101))
Decimal('1111')
- logical_xor(self, a, b)
- Applies the logical operation 'xor' between each operand's digits.
The operands must be both logical numbers.
>>> ExtendedContext.logical_xor(Decimal('0'), Decimal('0'))
Decimal('0')
>>> ExtendedContext.logical_xor(Decimal('0'), Decimal('1'))
Decimal('1')
>>> ExtendedContext.logical_xor(Decimal('1'), Decimal('0'))
Decimal('1')
>>> ExtendedContext.logical_xor(Decimal('1'), Decimal('1'))
Decimal('0')
>>> ExtendedContext.logical_xor(Decimal('1100'), Decimal('1010'))
Decimal('110')
>>> ExtendedContext.logical_xor(Decimal('1111'), Decimal('10'))
Decimal('1101')
>>> ExtendedContext.logical_xor(110, 1101)
Decimal('1011')
>>> ExtendedContext.logical_xor(Decimal(110), 1101)
Decimal('1011')
>>> ExtendedContext.logical_xor(110, Decimal(1101))
Decimal('1011')
- max(self, a, b)
- max compares two values numerically and returns the maximum.
If either operand is a NaN then the general rules apply.
Otherwise, the operands are compared as though by the compare
operation. If they are numerically equal then the left-hand operand
is chosen as the result. Otherwise the maximum (closer to positive
infinity) of the two operands is chosen as the result.
>>> ExtendedContext.max(Decimal('3'), Decimal('2'))
Decimal('3')
>>> ExtendedContext.max(Decimal('-10'), Decimal('3'))
Decimal('3')
>>> ExtendedContext.max(Decimal('1.0'), Decimal('1'))
Decimal('1')
>>> ExtendedContext.max(Decimal('7'), Decimal('NaN'))
Decimal('7')
>>> ExtendedContext.max(1, 2)
Decimal('2')
>>> ExtendedContext.max(Decimal(1), 2)
Decimal('2')
>>> ExtendedContext.max(1, Decimal(2))
Decimal('2')
- max_mag(self, a, b)
- Compares the values numerically with their sign ignored.
>>> ExtendedContext.max_mag(Decimal('7'), Decimal('NaN'))
Decimal('7')
>>> ExtendedContext.max_mag(Decimal('7'), Decimal('-10'))
Decimal('-10')
>>> ExtendedContext.max_mag(1, -2)
Decimal('-2')
>>> ExtendedContext.max_mag(Decimal(1), -2)
Decimal('-2')
>>> ExtendedContext.max_mag(1, Decimal(-2))
Decimal('-2')
- min(self, a, b)
- min compares two values numerically and returns the minimum.
If either operand is a NaN then the general rules apply.
Otherwise, the operands are compared as though by the compare
operation. If they are numerically equal then the left-hand operand
is chosen as the result. Otherwise the minimum (closer to negative
infinity) of the two operands is chosen as the result.
>>> ExtendedContext.min(Decimal('3'), Decimal('2'))
Decimal('2')
>>> ExtendedContext.min(Decimal('-10'), Decimal('3'))
Decimal('-10')
>>> ExtendedContext.min(Decimal('1.0'), Decimal('1'))
Decimal('1.0')
>>> ExtendedContext.min(Decimal('7'), Decimal('NaN'))
Decimal('7')
>>> ExtendedContext.min(1, 2)
Decimal('1')
>>> ExtendedContext.min(Decimal(1), 2)
Decimal('1')
>>> ExtendedContext.min(1, Decimal(29))
Decimal('1')
- min_mag(self, a, b)
- Compares the values numerically with their sign ignored.
>>> ExtendedContext.min_mag(Decimal('3'), Decimal('-2'))
Decimal('-2')
>>> ExtendedContext.min_mag(Decimal('-3'), Decimal('NaN'))
Decimal('-3')
>>> ExtendedContext.min_mag(1, -2)
Decimal('1')
>>> ExtendedContext.min_mag(Decimal(1), -2)
Decimal('1')
>>> ExtendedContext.min_mag(1, Decimal(-2))
Decimal('1')
- minus(self, a)
- Minus corresponds to unary prefix minus in Python.
The operation is evaluated using the same rules as subtract; the
operation minus(a) is calculated as subtract('0', a) where the '0'
has the same exponent as the operand.
>>> ExtendedContext.minus(Decimal('1.3'))
Decimal('-1.3')
>>> ExtendedContext.minus(Decimal('-1.3'))
Decimal('1.3')
>>> ExtendedContext.minus(1)
Decimal('-1')
- multiply(self, a, b)
- multiply multiplies two operands.
If either operand is a special value then the general rules apply.
Otherwise, the operands are multiplied together
('long multiplication'), resulting in a number which may be as long as
the sum of the lengths of the two operands.
>>> ExtendedContext.multiply(Decimal('1.20'), Decimal('3'))
Decimal('3.60')
>>> ExtendedContext.multiply(Decimal('7'), Decimal('3'))
Decimal('21')
>>> ExtendedContext.multiply(Decimal('0.9'), Decimal('0.8'))
Decimal('0.72')
>>> ExtendedContext.multiply(Decimal('0.9'), Decimal('-0'))
Decimal('-0.0')
>>> ExtendedContext.multiply(Decimal('654321'), Decimal('654321'))
Decimal('4.28135971E+11')
>>> ExtendedContext.multiply(7, 7)
Decimal('49')
>>> ExtendedContext.multiply(Decimal(7), 7)
Decimal('49')
>>> ExtendedContext.multiply(7, Decimal(7))
Decimal('49')
- next_minus(self, a)
- Returns the largest representable number smaller than a.
>>> c = ExtendedContext.copy()
>>> c.Emin = -999
>>> c.Emax = 999
>>> ExtendedContext.next_minus(Decimal('1'))
Decimal('0.999999999')
>>> c.next_minus(Decimal('1E-1007'))
Decimal('0E-1007')
>>> ExtendedContext.next_minus(Decimal('-1.00000003'))
Decimal('-1.00000004')
>>> c.next_minus(Decimal('Infinity'))
Decimal('9.99999999E+999')
>>> c.next_minus(1)
Decimal('0.999999999')
- next_plus(self, a)
- Returns the smallest representable number larger than a.
>>> c = ExtendedContext.copy()
>>> c.Emin = -999
>>> c.Emax = 999
>>> ExtendedContext.next_plus(Decimal('1'))
Decimal('1.00000001')
>>> c.next_plus(Decimal('-1E-1007'))
Decimal('-0E-1007')
>>> ExtendedContext.next_plus(Decimal('-1.00000003'))
Decimal('-1.00000002')
>>> c.next_plus(Decimal('-Infinity'))
Decimal('-9.99999999E+999')
>>> c.next_plus(1)
Decimal('1.00000001')
- next_toward(self, a, b)
- Returns the number closest to a, in direction towards b.
The result is the closest representable number from the first
operand (but not the first operand) that is in the direction
towards the second operand, unless the operands have the same
value.
>>> c = ExtendedContext.copy()
>>> c.Emin = -999
>>> c.Emax = 999
>>> c.next_toward(Decimal('1'), Decimal('2'))
Decimal('1.00000001')
>>> c.next_toward(Decimal('-1E-1007'), Decimal('1'))
Decimal('-0E-1007')
>>> c.next_toward(Decimal('-1.00000003'), Decimal('0'))
Decimal('-1.00000002')
>>> c.next_toward(Decimal('1'), Decimal('0'))
Decimal('0.999999999')
>>> c.next_toward(Decimal('1E-1007'), Decimal('-100'))
Decimal('0E-1007')
>>> c.next_toward(Decimal('-1.00000003'), Decimal('-10'))
Decimal('-1.00000004')
>>> c.next_toward(Decimal('0.00'), Decimal('-0.0000'))
Decimal('-0.00')
>>> c.next_toward(0, 1)
Decimal('1E-1007')
>>> c.next_toward(Decimal(0), 1)
Decimal('1E-1007')
>>> c.next_toward(0, Decimal(1))
Decimal('1E-1007')
- normalize(self, a)
- normalize reduces an operand to its simplest form.
Essentially a plus operation with all trailing zeros removed from the
result.
>>> ExtendedContext.normalize(Decimal('2.1'))
Decimal('2.1')
>>> ExtendedContext.normalize(Decimal('-2.0'))
Decimal('-2')
>>> ExtendedContext.normalize(Decimal('1.200'))
Decimal('1.2')
>>> ExtendedContext.normalize(Decimal('-120'))
Decimal('-1.2E+2')
>>> ExtendedContext.normalize(Decimal('120.00'))
Decimal('1.2E+2')
>>> ExtendedContext.normalize(Decimal('0.00'))
Decimal('0')
>>> ExtendedContext.normalize(6)
Decimal('6')
- number_class(self, a)
- Returns an indication of the class of the operand.
The class is one of the following strings:
-sNaN
-NaN
-Infinity
-Normal
-Subnormal
-Zero
+Zero
+Subnormal
+Normal
+Infinity
>>> c = Context(ExtendedContext)
>>> c.Emin = -999
>>> c.Emax = 999
>>> c.number_class(Decimal('Infinity'))
'+Infinity'
>>> c.number_class(Decimal('1E-10'))
'+Normal'
>>> c.number_class(Decimal('2.50'))
'+Normal'
>>> c.number_class(Decimal('0.1E-999'))
'+Subnormal'
>>> c.number_class(Decimal('0'))
'+Zero'
>>> c.number_class(Decimal('-0'))
'-Zero'
>>> c.number_class(Decimal('-0.1E-999'))
'-Subnormal'
>>> c.number_class(Decimal('-1E-10'))
'-Normal'
>>> c.number_class(Decimal('-2.50'))
'-Normal'
>>> c.number_class(Decimal('-Infinity'))
'-Infinity'
>>> c.number_class(Decimal('NaN'))
'NaN'
>>> c.number_class(Decimal('-NaN'))
'NaN'
>>> c.number_class(Decimal('sNaN'))
'sNaN'
>>> c.number_class(123)
'+Normal'
- plus(self, a)
- Plus corresponds to unary prefix plus in Python.
The operation is evaluated using the same rules as add; the
operation plus(a) is calculated as add('0', a) where the '0'
has the same exponent as the operand.
>>> ExtendedContext.plus(Decimal('1.3'))
Decimal('1.3')
>>> ExtendedContext.plus(Decimal('-1.3'))
Decimal('-1.3')
>>> ExtendedContext.plus(-1)
Decimal('-1')
- power(self, a, b, modulo=None)
- Raises a to the power of b, to modulo if given.
With two arguments, compute a**b. If a is negative then b
must be integral. The result will be inexact unless b is
integral and the result is finite and can be expressed exactly
in 'precision' digits.
With three arguments, compute (a**b) % modulo. For the
three argument form, the following restrictions on the
arguments hold:
- all three arguments must be integral
- b must be nonnegative
- at least one of a or b must be nonzero
- modulo must be nonzero and have at most 'precision' digits
The result of pow(a, b, modulo) is identical to the result
that would be obtained by computing (a**b) % modulo with
unbounded precision, but is computed more efficiently. It is
always exact.
>>> c = ExtendedContext.copy()
>>> c.Emin = -999
>>> c.Emax = 999
>>> c.power(Decimal('2'), Decimal('3'))
Decimal('8')
>>> c.power(Decimal('-2'), Decimal('3'))
Decimal('-8')
>>> c.power(Decimal('2'), Decimal('-3'))
Decimal('0.125')
>>> c.power(Decimal('1.7'), Decimal('8'))
Decimal('69.7575744')
>>> c.power(Decimal('10'), Decimal('0.301029996'))
Decimal('2.00000000')
>>> c.power(Decimal('Infinity'), Decimal('-1'))
Decimal('0')
>>> c.power(Decimal('Infinity'), Decimal('0'))
Decimal('1')
>>> c.power(Decimal('Infinity'), Decimal('1'))
Decimal('Infinity')
>>> c.power(Decimal('-Infinity'), Decimal('-1'))
Decimal('-0')
>>> c.power(Decimal('-Infinity'), Decimal('0'))
Decimal('1')
>>> c.power(Decimal('-Infinity'), Decimal('1'))
Decimal('-Infinity')
>>> c.power(Decimal('-Infinity'), Decimal('2'))
Decimal('Infinity')
>>> c.power(Decimal('0'), Decimal('0'))
Decimal('NaN')
>>> c.power(Decimal('3'), Decimal('7'), Decimal('16'))
Decimal('11')
>>> c.power(Decimal('-3'), Decimal('7'), Decimal('16'))
Decimal('-11')
>>> c.power(Decimal('-3'), Decimal('8'), Decimal('16'))
Decimal('1')
>>> c.power(Decimal('3'), Decimal('7'), Decimal('-16'))
Decimal('11')
>>> c.power(Decimal('23E12345'), Decimal('67E189'), Decimal('123456789'))
Decimal('11729830')
>>> c.power(Decimal('-0'), Decimal('17'), Decimal('1729'))
Decimal('-0')
>>> c.power(Decimal('-23'), Decimal('0'), Decimal('65537'))
Decimal('1')
>>> ExtendedContext.power(7, 7)
Decimal('823543')
>>> ExtendedContext.power(Decimal(7), 7)
Decimal('823543')
>>> ExtendedContext.power(7, Decimal(7), 2)
Decimal('1')
- quantize(self, a, b)
- Returns a value equal to 'a' (rounded), having the exponent of 'b'.
The coefficient of the result is derived from that of the left-hand
operand. It may be rounded using the current rounding setting (if the
exponent is being increased), multiplied by a positive power of ten (if
the exponent is being decreased), or is unchanged (if the exponent is
already equal to that of the right-hand operand).
Unlike other operations, if the length of the coefficient after the
quantize operation would be greater than precision then an Invalid
operation condition is raised. This guarantees that, unless there is
an error condition, the exponent of the result of a quantize is always
equal to that of the right-hand operand.
Also unlike other operations, quantize will never raise Underflow, even
if the result is subnormal and inexact.
>>> ExtendedContext.quantize(Decimal('2.17'), Decimal('0.001'))
Decimal('2.170')
>>> ExtendedContext.quantize(Decimal('2.17'), Decimal('0.01'))
Decimal('2.17')
>>> ExtendedContext.quantize(Decimal('2.17'), Decimal('0.1'))
Decimal('2.2')
>>> ExtendedContext.quantize(Decimal('2.17'), Decimal('1e+0'))
Decimal('2')
>>> ExtendedContext.quantize(Decimal('2.17'), Decimal('1e+1'))
Decimal('0E+1')
>>> ExtendedContext.quantize(Decimal('-Inf'), Decimal('Infinity'))
Decimal('-Infinity')
>>> ExtendedContext.quantize(Decimal('2'), Decimal('Infinity'))
Decimal('NaN')
>>> ExtendedContext.quantize(Decimal('-0.1'), Decimal('1'))
Decimal('-0')
>>> ExtendedContext.quantize(Decimal('-0'), Decimal('1e+5'))
Decimal('-0E+5')
>>> ExtendedContext.quantize(Decimal('+35236450.6'), Decimal('1e-2'))
Decimal('NaN')
>>> ExtendedContext.quantize(Decimal('-35236450.6'), Decimal('1e-2'))
Decimal('NaN')
>>> ExtendedContext.quantize(Decimal('217'), Decimal('1e-1'))
Decimal('217.0')
>>> ExtendedContext.quantize(Decimal('217'), Decimal('1e-0'))
Decimal('217')
>>> ExtendedContext.quantize(Decimal('217'), Decimal('1e+1'))
Decimal('2.2E+2')
>>> ExtendedContext.quantize(Decimal('217'), Decimal('1e+2'))
Decimal('2E+2')
>>> ExtendedContext.quantize(1, 2)
Decimal('1')
>>> ExtendedContext.quantize(Decimal(1), 2)
Decimal('1')
>>> ExtendedContext.quantize(1, Decimal(2))
Decimal('1')
- radix(self)
- Just returns 10, as this is Decimal, :)
>>> ExtendedContext.radix()
Decimal('10')
- remainder(self, a, b)
- Returns the remainder from integer division.
The result is the residue of the dividend after the operation of
calculating integer division as described for divide-integer, rounded
to precision digits if necessary. The sign of the result, if
non-zero, is the same as that of the original dividend.
This operation will fail under the same conditions as integer division
(that is, if integer division on the same two operands would fail, the
remainder cannot be calculated).
>>> ExtendedContext.remainder(Decimal('2.1'), Decimal('3'))
Decimal('2.1')
>>> ExtendedContext.remainder(Decimal('10'), Decimal('3'))
Decimal('1')
>>> ExtendedContext.remainder(Decimal('-10'), Decimal('3'))
Decimal('-1')
>>> ExtendedContext.remainder(Decimal('10.2'), Decimal('1'))
Decimal('0.2')
>>> ExtendedContext.remainder(Decimal('10'), Decimal('0.3'))
Decimal('0.1')
>>> ExtendedContext.remainder(Decimal('3.6'), Decimal('1.3'))
Decimal('1.0')
>>> ExtendedContext.remainder(22, 6)
Decimal('4')
>>> ExtendedContext.remainder(Decimal(22), 6)
Decimal('4')
>>> ExtendedContext.remainder(22, Decimal(6))
Decimal('4')
- remainder_near(self, a, b)
- Returns to be "a - b * n", where n is the integer nearest the exact
value of "x / b" (if two integers are equally near then the even one
is chosen). If the result is equal to 0 then its sign will be the
sign of a.
This operation will fail under the same conditions as integer division
(that is, if integer division on the same two operands would fail, the
remainder cannot be calculated).
>>> ExtendedContext.remainder_near(Decimal('2.1'), Decimal('3'))
Decimal('-0.9')
>>> ExtendedContext.remainder_near(Decimal('10'), Decimal('6'))
Decimal('-2')
>>> ExtendedContext.remainder_near(Decimal('10'), Decimal('3'))
Decimal('1')
>>> ExtendedContext.remainder_near(Decimal('-10'), Decimal('3'))
Decimal('-1')
>>> ExtendedContext.remainder_near(Decimal('10.2'), Decimal('1'))
Decimal('0.2')
>>> ExtendedContext.remainder_near(Decimal('10'), Decimal('0.3'))
Decimal('0.1')
>>> ExtendedContext.remainder_near(Decimal('3.6'), Decimal('1.3'))
Decimal('-0.3')
>>> ExtendedContext.remainder_near(3, 11)
Decimal('3')
>>> ExtendedContext.remainder_near(Decimal(3), 11)
Decimal('3')
>>> ExtendedContext.remainder_near(3, Decimal(11))
Decimal('3')
- rotate(self, a, b)
- Returns a rotated copy of a, b times.
The coefficient of the result is a rotated copy of the digits in
the coefficient of the first operand. The number of places of
rotation is taken from the absolute value of the second operand,
with the rotation being to the left if the second operand is
positive or to the right otherwise.
>>> ExtendedContext.rotate(Decimal('34'), Decimal('8'))
Decimal('400000003')
>>> ExtendedContext.rotate(Decimal('12'), Decimal('9'))
Decimal('12')
>>> ExtendedContext.rotate(Decimal('123456789'), Decimal('-2'))
Decimal('891234567')
>>> ExtendedContext.rotate(Decimal('123456789'), Decimal('0'))
Decimal('123456789')
>>> ExtendedContext.rotate(Decimal('123456789'), Decimal('+2'))
Decimal('345678912')
>>> ExtendedContext.rotate(1333333, 1)
Decimal('13333330')
>>> ExtendedContext.rotate(Decimal(1333333), 1)
Decimal('13333330')
>>> ExtendedContext.rotate(1333333, Decimal(1))
Decimal('13333330')
- same_quantum(self, a, b)
- Returns True if the two operands have the same exponent.
The result is never affected by either the sign or the coefficient of
either operand.
>>> ExtendedContext.same_quantum(Decimal('2.17'), Decimal('0.001'))
False
>>> ExtendedContext.same_quantum(Decimal('2.17'), Decimal('0.01'))
True
>>> ExtendedContext.same_quantum(Decimal('2.17'), Decimal('1'))
False
>>> ExtendedContext.same_quantum(Decimal('Inf'), Decimal('-Inf'))
True
>>> ExtendedContext.same_quantum(10000, -1)
True
>>> ExtendedContext.same_quantum(Decimal(10000), -1)
True
>>> ExtendedContext.same_quantum(10000, Decimal(-1))
True
- scaleb(self, a, b)
- Returns the first operand after adding the second value its exp.
>>> ExtendedContext.scaleb(Decimal('7.50'), Decimal('-2'))
Decimal('0.0750')
>>> ExtendedContext.scaleb(Decimal('7.50'), Decimal('0'))
Decimal('7.50')
>>> ExtendedContext.scaleb(Decimal('7.50'), Decimal('3'))
Decimal('7.50E+3')
>>> ExtendedContext.scaleb(1, 4)
Decimal('1E+4')
>>> ExtendedContext.scaleb(Decimal(1), 4)
Decimal('1E+4')
>>> ExtendedContext.scaleb(1, Decimal(4))
Decimal('1E+4')
- shift(self, a, b)
- Returns a shifted copy of a, b times.
The coefficient of the result is a shifted copy of the digits
in the coefficient of the first operand. The number of places
to shift is taken from the absolute value of the second operand,
with the shift being to the left if the second operand is
positive or to the right otherwise. Digits shifted into the
coefficient are zeros.
>>> ExtendedContext.shift(Decimal('34'), Decimal('8'))
Decimal('400000000')
>>> ExtendedContext.shift(Decimal('12'), Decimal('9'))
Decimal('0')
>>> ExtendedContext.shift(Decimal('123456789'), Decimal('-2'))
Decimal('1234567')
>>> ExtendedContext.shift(Decimal('123456789'), Decimal('0'))
Decimal('123456789')
>>> ExtendedContext.shift(Decimal('123456789'), Decimal('+2'))
Decimal('345678900')
>>> ExtendedContext.shift(88888888, 2)
Decimal('888888800')
>>> ExtendedContext.shift(Decimal(88888888), 2)
Decimal('888888800')
>>> ExtendedContext.shift(88888888, Decimal(2))
Decimal('888888800')
- sqrt(self, a)
- Square root of a non-negative number to context precision.
If the result must be inexact, it is rounded using the round-half-even
algorithm.
>>> ExtendedContext.sqrt(Decimal('0'))
Decimal('0')
>>> ExtendedContext.sqrt(Decimal('-0'))
Decimal('-0')
>>> ExtendedContext.sqrt(Decimal('0.39'))
Decimal('0.624499800')
>>> ExtendedContext.sqrt(Decimal('100'))
Decimal('10')
>>> ExtendedContext.sqrt(Decimal('1'))
Decimal('1')
>>> ExtendedContext.sqrt(Decimal('1.0'))
Decimal('1.0')
>>> ExtendedContext.sqrt(Decimal('1.00'))
Decimal('1.0')
>>> ExtendedContext.sqrt(Decimal('7'))
Decimal('2.64575131')
>>> ExtendedContext.sqrt(Decimal('10'))
Decimal('3.16227766')
>>> ExtendedContext.sqrt(2)
Decimal('1.41421356')
>>> ExtendedContext.prec
9
- subtract(self, a, b)
- Return the difference between the two operands.
>>> ExtendedContext.subtract(Decimal('1.3'), Decimal('1.07'))
Decimal('0.23')
>>> ExtendedContext.subtract(Decimal('1.3'), Decimal('1.30'))
Decimal('0.00')
>>> ExtendedContext.subtract(Decimal('1.3'), Decimal('2.07'))
Decimal('-0.77')
>>> ExtendedContext.subtract(8, 5)
Decimal('3')
>>> ExtendedContext.subtract(Decimal(8), 5)
Decimal('3')
>>> ExtendedContext.subtract(8, Decimal(5))
Decimal('3')
- to_eng_string(self, a)
- Converts a number to a string, using scientific notation.
The operation is not affected by the context.
- to_integral = to_integral_value(self, a)
- to_integral_exact(self, a)
- Rounds to an integer.
When the operand has a negative exponent, the result is the same
as using the quantize() operation using the given operand as the
left-hand-operand, 1E+0 as the right-hand-operand, and the precision
of the operand as the precision setting; Inexact and Rounded flags
are allowed in this operation. The rounding mode is taken from the
context.
>>> ExtendedContext.to_integral_exact(Decimal('2.1'))
Decimal('2')
>>> ExtendedContext.to_integral_exact(Decimal('100'))
Decimal('100')
>>> ExtendedContext.to_integral_exact(Decimal('100.0'))
Decimal('100')
>>> ExtendedContext.to_integral_exact(Decimal('101.5'))
Decimal('102')
>>> ExtendedContext.to_integral_exact(Decimal('-101.5'))
Decimal('-102')
>>> ExtendedContext.to_integral_exact(Decimal('10E+5'))
Decimal('1.0E+6')
>>> ExtendedContext.to_integral_exact(Decimal('7.89E+77'))
Decimal('7.89E+77')
>>> ExtendedContext.to_integral_exact(Decimal('-Inf'))
Decimal('-Infinity')
- to_integral_value(self, a)
- Rounds to an integer.
When the operand has a negative exponent, the result is the same
as using the quantize() operation using the given operand as the
left-hand-operand, 1E+0 as the right-hand-operand, and the precision
of the operand as the precision setting, except that no flags will
be set. The rounding mode is taken from the context.
>>> ExtendedContext.to_integral_value(Decimal('2.1'))
Decimal('2')
>>> ExtendedContext.to_integral_value(Decimal('100'))
Decimal('100')
>>> ExtendedContext.to_integral_value(Decimal('100.0'))
Decimal('100')
>>> ExtendedContext.to_integral_value(Decimal('101.5'))
Decimal('102')
>>> ExtendedContext.to_integral_value(Decimal('-101.5'))
Decimal('-102')
>>> ExtendedContext.to_integral_value(Decimal('10E+5'))
Decimal('1.0E+6')
>>> ExtendedContext.to_integral_value(Decimal('7.89E+77'))
Decimal('7.89E+77')
>>> ExtendedContext.to_integral_value(Decimal('-Inf'))
Decimal('-Infinity')
- to_sci_string(self, a)
- Converts a number to a string, using scientific notation.
The operation is not affected by the context.
Data descriptors defined here:
- __dict__
- dictionary for instance variables (if defined)
- __weakref__
- list of weak references to the object (if defined)
Data and other attributes defined here:
- __hash__ = None
|
class Decimal(__builtin__.object) |
| |
Floating point class for decimal arithmetic.
|
| |
Methods defined here:
- __abs__(self, round=True, context=None)
- Returns the absolute value of self.
If the keyword argument 'round' is false, do not round. The
expression self.__abs__(round=False) is equivalent to
self.copy_abs().
- __add__(self, other, context=None)
- Returns self + other.
-INF + INF (or the reverse) cause InvalidOperation errors.
- __complex__(self)
- __copy__(self)
- __deepcopy__(self, memo)
- __div__ = __truediv__(self, other, context=None)
- __divmod__(self, other, context=None)
- Return (self // other, self % other)
- __eq__(self, other, context=None)
- __float__(self)
- Float representation.
- __floordiv__(self, other, context=None)
- self // other
- __format__(self, specifier, context=None, _localeconv=None)
- Format a Decimal instance according to the given specifier.
The specifier should be a standard format specifier, with the
form described in PEP 3101. Formatting types 'e', 'E', 'f',
'F', 'g', 'G', 'n' and '%' are supported. If the formatting
type is omitted it defaults to 'g' or 'G', depending on the
value of context.capitals.
- __ge__(self, other, context=None)
- __gt__(self, other, context=None)
- __hash__(self)
- x.__hash__() <==> hash(x)
- __int__(self)
- Converts self to an int, truncating if necessary.
- __le__(self, other, context=None)
- __long__(self)
- Converts to a long.
Equivalent to long(int(self))
- __lt__(self, other, context=None)
- __mod__(self, other, context=None)
- self % other
- __mul__(self, other, context=None)
- Return self * other.
(+-) INF * 0 (or its reverse) raise InvalidOperation.
- __ne__(self, other, context=None)
- __neg__(self, context=None)
- Returns a copy with the sign switched.
Rounds, if it has reason.
- __nonzero__(self)
- Return True if self is nonzero; otherwise return False.
NaNs and infinities are considered nonzero.
- __pos__(self, context=None)
- Returns a copy, unless it is a sNaN.
Rounds the number (if more then precision digits)
- __pow__(self, other, modulo=None, context=None)
- Return self ** other [ % modulo].
With two arguments, compute self**other.
With three arguments, compute (self**other) % modulo. For the
three argument form, the following restrictions on the
arguments hold:
- all three arguments must be integral
- other must be nonnegative
- either self or other (or both) must be nonzero
- modulo must be nonzero and must have at most p digits,
where p is the context precision.
If any of these restrictions is violated the InvalidOperation
flag is raised.
The result of pow(self, other, modulo) is identical to the
result that would be obtained by computing (self**other) %
modulo with unbounded precision, but is computed more
efficiently. It is always exact.
- __radd__ = __add__(self, other, context=None)
- __rdiv__ = __rtruediv__(self, other, context=None)
- __rdivmod__(self, other, context=None)
- Swaps self/other and returns __divmod__.
- __reduce__(self)
- # Support for pickling, copy, and deepcopy
- __repr__(self)
- Represents the number as an instance of Decimal.
- __rfloordiv__(self, other, context=None)
- Swaps self/other and returns __floordiv__.
- __rmod__(self, other, context=None)
- Swaps self/other and returns __mod__.
- __rmul__ = __mul__(self, other, context=None)
- __rpow__(self, other, context=None)
- Swaps self/other and returns __pow__.
- __rsub__(self, other, context=None)
- Return other - self
- __rtruediv__(self, other, context=None)
- Swaps self/other and returns __truediv__.
- __str__(self, eng=False, context=None)
- Return string representation of the number in scientific notation.
Captures all of the information in the underlying representation.
- __sub__(self, other, context=None)
- Return self - other
- __truediv__(self, other, context=None)
- Return self / other.
- __trunc__ = __int__(self)
- adjusted(self)
- Return the adjusted exponent of self
- as_tuple(self)
- Represents the number as a triple tuple.
To show the internals exactly as they are.
- canonical(self, context=None)
- Returns the same Decimal object.
As we do not have different encodings for the same number, the
received object already is in its canonical form.
- compare(self, other, context=None)
- Compares one to another.
-1 => a < b
0 => a = b
1 => a > b
NaN => one is NaN
Like __cmp__, but returns Decimal instances.
- compare_signal(self, other, context=None)
- Compares self to the other operand numerically.
It's pretty much like compare(), but all NaNs signal, with signaling
NaNs taking precedence over quiet NaNs.
- compare_total(self, other)
- Compares self to other using the abstract representations.
This is not like the standard compare, which use their numerical
value. Note that a total ordering is defined for all possible abstract
representations.
- compare_total_mag(self, other)
- Compares self to other using abstract repr., ignoring sign.
Like compare_total, but with operand's sign ignored and assumed to be 0.
- conjugate(self)
- copy_abs(self)
- Returns a copy with the sign set to 0.
- copy_negate(self)
- Returns a copy with the sign inverted.
- copy_sign(self, other)
- Returns self with the sign of other.
- exp(self, context=None)
- Returns e ** self.
- fma(self, other, third, context=None)
- Fused multiply-add.
Returns self*other+third with no rounding of the intermediate
product self*other.
self and other are multiplied together, with no rounding of
the result. The third operand is then added to the result,
and a single final rounding is performed.
- is_canonical(self)
- Return True if self is canonical; otherwise return False.
Currently, the encoding of a Decimal instance is always
canonical, so this method returns True for any Decimal.
- is_finite(self)
- Return True if self is finite; otherwise return False.
A Decimal instance is considered finite if it is neither
infinite nor a NaN.
- is_infinite(self)
- Return True if self is infinite; otherwise return False.
- is_nan(self)
- Return True if self is a qNaN or sNaN; otherwise return False.
- is_normal(self, context=None)
- Return True if self is a normal number; otherwise return False.
- is_qnan(self)
- Return True if self is a quiet NaN; otherwise return False.
- is_signed(self)
- Return True if self is negative; otherwise return False.
- is_snan(self)
- Return True if self is a signaling NaN; otherwise return False.
- is_subnormal(self, context=None)
- Return True if self is subnormal; otherwise return False.
- is_zero(self)
- Return True if self is a zero; otherwise return False.
- ln(self, context=None)
- Returns the natural (base e) logarithm of self.
- log10(self, context=None)
- Returns the base 10 logarithm of self.
- logb(self, context=None)
- Returns the exponent of the magnitude of self's MSD.
The result is the integer which is the exponent of the magnitude
of the most significant digit of self (as though it were truncated
to a single digit while maintaining the value of that digit and
without limiting the resulting exponent).
- logical_and(self, other, context=None)
- Applies an 'and' operation between self and other's digits.
- logical_invert(self, context=None)
- Invert all its digits.
- logical_or(self, other, context=None)
- Applies an 'or' operation between self and other's digits.
- logical_xor(self, other, context=None)
- Applies an 'xor' operation between self and other's digits.
- max(self, other, context=None)
- Returns the larger value.
Like max(self, other) except if one is not a number, returns
NaN (and signals if one is sNaN). Also rounds.
- max_mag(self, other, context=None)
- Compares the values numerically with their sign ignored.
- min(self, other, context=None)
- Returns the smaller value.
Like min(self, other) except if one is not a number, returns
NaN (and signals if one is sNaN). Also rounds.
- min_mag(self, other, context=None)
- Compares the values numerically with their sign ignored.
- next_minus(self, context=None)
- Returns the largest representable number smaller than itself.
- next_plus(self, context=None)
- Returns the smallest representable number larger than itself.
- next_toward(self, other, context=None)
- Returns the number closest to self, in the direction towards other.
The result is the closest representable number to self
(excluding self) that is in the direction towards other,
unless both have the same value. If the two operands are
numerically equal, then the result is a copy of self with the
sign set to be the same as the sign of other.
- normalize(self, context=None)
- Normalize- strip trailing 0s, change anything equal to 0 to 0e0
- number_class(self, context=None)
- Returns an indication of the class of self.
The class is one of the following strings:
sNaN
NaN
-Infinity
-Normal
-Subnormal
-Zero
+Zero
+Subnormal
+Normal
+Infinity
- quantize(self, exp, rounding=None, context=None, watchexp=True)
- Quantize self so its exponent is the same as that of exp.
Similar to self._rescale(exp._exp) but with error checking.
- radix(self)
- Just returns 10, as this is Decimal, :)
- remainder_near(self, other, context=None)
- Remainder nearest to 0- abs(remainder-near) <= other/2
- rotate(self, other, context=None)
- Returns a rotated copy of self, value-of-other times.
- same_quantum(self, other)
- Return True if self and other have the same exponent; otherwise
return False.
If either operand is a special value, the following rules are used:
* return True if both operands are infinities
* return True if both operands are NaNs
* otherwise, return False.
- scaleb(self, other, context=None)
- Returns self operand after adding the second value to its exp.
- shift(self, other, context=None)
- Returns a shifted copy of self, value-of-other times.
- sqrt(self, context=None)
- Return the square root of self.
- to_eng_string(self, context=None)
- Convert to engineering-type string.
Engineering notation has an exponent which is a multiple of 3, so there
are up to 3 digits left of the decimal place.
Same rules for when in exponential and when as a value as in __str__.
- to_integral = to_integral_value(self, rounding=None, context=None)
- to_integral_exact(self, rounding=None, context=None)
- Rounds to a nearby integer.
If no rounding mode is specified, take the rounding mode from
the context. This method raises the Rounded and Inexact flags
when appropriate.
See also: to_integral_value, which does exactly the same as
this method except that it doesn't raise Inexact or Rounded.
- to_integral_value(self, rounding=None, context=None)
- Rounds to the nearest integer, without raising inexact, rounded.
Class methods defined here:
- from_float(cls, f) from __builtin__.type
- Converts a float to a decimal number, exactly.
Note that Decimal.from_float(0.1) is not the same as Decimal('0.1').
Since 0.1 is not exactly representable in binary floating point, the
value is stored as the nearest representable value which is
0x1.999999999999ap-4. The exact equivalent of the value in decimal
is 0.1000000000000000055511151231257827021181583404541015625.
>>> Decimal.from_float(0.1)
Decimal('0.1000000000000000055511151231257827021181583404541015625')
>>> Decimal.from_float(float('nan'))
Decimal('NaN')
>>> Decimal.from_float(float('inf'))
Decimal('Infinity')
>>> Decimal.from_float(-float('inf'))
Decimal('-Infinity')
>>> Decimal.from_float(-0.0)
Decimal('-0')
Static methods defined here:
- __new__(cls, value='0', context=None)
- Create a decimal point instance.
>>> Decimal('3.14') # string input
Decimal('3.14')
>>> Decimal((0, (3, 1, 4), -2)) # tuple (sign, digit_tuple, exponent)
Decimal('3.14')
>>> Decimal(314) # int or long
Decimal('314')
>>> Decimal(Decimal(314)) # another decimal instance
Decimal('314')
>>> Decimal(' 3.14 \n') # leading and trailing whitespace okay
Decimal('3.14')
Data descriptors defined here:
- imag
- real
|
class DecimalException(exceptions.ArithmeticError) |
| |
Base exception class.
Used exceptions derive from this.
If an exception derives from another exception besides this (such as
Underflow (Inexact, Rounded, Subnormal) that indicates that it is only
called if the others are present. This isn't actually used for
anything, though.
handle -- Called when context._raise_error is called and the
trap_enabler is not set. First argument is self, second is the
context. More arguments can be given, those being after
the explanation in _raise_error (For example,
context._raise_error(NewError, '(-x)!', self._sign) would
call NewError().handle(context, self._sign).)
To define a new exception, it should be sufficient to have it derive
from DecimalException.
|
| |
- Method resolution order:
- DecimalException
- exceptions.ArithmeticError
- exceptions.StandardError
- exceptions.Exception
- exceptions.BaseException
- __builtin__.object
Methods defined here:
- handle(self, context, *args)
Data descriptors defined here:
- __weakref__
- list of weak references to the object (if defined)
Methods inherited from exceptions.ArithmeticError:
- __init__(...)
- x.__init__(...) initializes x; see help(type(x)) for signature
Data and other attributes inherited from exceptions.ArithmeticError:
- __new__ = <built-in method __new__ of type object>
- T.__new__(S, ...) -> a new object with type S, a subtype of T
Methods inherited from exceptions.BaseException:
- __delattr__(...)
- x.__delattr__('name') <==> del x.name
- __getattribute__(...)
- x.__getattribute__('name') <==> x.name
- __getitem__(...)
- x.__getitem__(y) <==> x[y]
- __getslice__(...)
- x.__getslice__(i, j) <==> x[i:j]
Use of negative indices is not supported.
- __reduce__(...)
- __repr__(...)
- x.__repr__() <==> repr(x)
- __setattr__(...)
- x.__setattr__('name', value) <==> x.name = value
- __setstate__(...)
- __str__(...)
- x.__str__() <==> str(x)
- __unicode__(...)
Data descriptors inherited from exceptions.BaseException:
- __dict__
- args
- message
|
class DivisionByZero(DecimalException, exceptions.ZeroDivisionError) |
| |
Division by 0.
This occurs and signals division-by-zero if division of a finite number
by zero was attempted (during a divide-integer or divide operation, or a
power operation with negative right-hand operand), and the dividend was
not zero.
The result of the operation is [sign,inf], where sign is the exclusive
or of the signs of the operands for divide, or is 1 for an odd power of
-0, for power.
|
| |
- Method resolution order:
- DivisionByZero
- DecimalException
- exceptions.ZeroDivisionError
- exceptions.ArithmeticError
- exceptions.StandardError
- exceptions.Exception
- exceptions.BaseException
- __builtin__.object
Methods defined here:
- handle(self, context, sign, *args)
Data descriptors inherited from DecimalException:
- __weakref__
- list of weak references to the object (if defined)
Methods inherited from exceptions.ZeroDivisionError:
- __init__(...)
- x.__init__(...) initializes x; see help(type(x)) for signature
Data and other attributes inherited from exceptions.ZeroDivisionError:
- __new__ = <built-in method __new__ of type object>
- T.__new__(S, ...) -> a new object with type S, a subtype of T
Methods inherited from exceptions.BaseException:
- __delattr__(...)
- x.__delattr__('name') <==> del x.name
- __getattribute__(...)
- x.__getattribute__('name') <==> x.name
- __getitem__(...)
- x.__getitem__(y) <==> x[y]
- __getslice__(...)
- x.__getslice__(i, j) <==> x[i:j]
Use of negative indices is not supported.
- __reduce__(...)
- __repr__(...)
- x.__repr__() <==> repr(x)
- __setattr__(...)
- x.__setattr__('name', value) <==> x.name = value
- __setstate__(...)
- __str__(...)
- x.__str__() <==> str(x)
- __unicode__(...)
Data descriptors inherited from exceptions.BaseException:
- __dict__
- args
- message
|
class InvalidOperation(DecimalException) |
| |
An invalid operation was performed.
Various bad things cause this:
Something creates a signaling NaN
-INF + INF
0 * (+-)INF
(+-)INF / (+-)INF
x % 0
(+-)INF % x
x._rescale( non-integer )
sqrt(-x) , x > 0
0 ** 0
x ** (non-integer)
x ** (+-)INF
An operand is invalid
The result of the operation after these is a quiet positive NaN,
except when the cause is a signaling NaN, in which case the result is
also a quiet NaN, but with the original sign, and an optional
diagnostic information.
|
| |
- Method resolution order:
- InvalidOperation
- DecimalException
- exceptions.ArithmeticError
- exceptions.StandardError
- exceptions.Exception
- exceptions.BaseException
- __builtin__.object
Methods defined here:
- handle(self, context, *args)
Data descriptors inherited from DecimalException:
- __weakref__
- list of weak references to the object (if defined)
Methods inherited from exceptions.ArithmeticError:
- __init__(...)
- x.__init__(...) initializes x; see help(type(x)) for signature
Data and other attributes inherited from exceptions.ArithmeticError:
- __new__ = <built-in method __new__ of type object>
- T.__new__(S, ...) -> a new object with type S, a subtype of T
Methods inherited from exceptions.BaseException:
- __delattr__(...)
- x.__delattr__('name') <==> del x.name
- __getattribute__(...)
- x.__getattribute__('name') <==> x.name
- __getitem__(...)
- x.__getitem__(y) <==> x[y]
- __getslice__(...)
- x.__getslice__(i, j) <==> x[i:j]
Use of negative indices is not supported.
- __reduce__(...)
- __repr__(...)
- x.__repr__() <==> repr(x)
- __setattr__(...)
- x.__setattr__('name', value) <==> x.name = value
- __setstate__(...)
- __str__(...)
- x.__str__() <==> str(x)
- __unicode__(...)
Data descriptors inherited from exceptions.BaseException:
- __dict__
- args
- message
|
class Overflow(Inexact, Rounded) |
| |
Numerical overflow.
This occurs and signals overflow if the adjusted exponent of a result
(from a conversion or from an operation that is not an attempt to divide
by zero), after rounding, would be greater than the largest value that
can be handled by the implementation (the value Emax).
The result depends on the rounding mode:
For round-half-up and round-half-even (and for round-half-down and
round-up, if implemented), the result of the operation is [sign,inf],
where sign is the sign of the intermediate result. For round-down, the
result is the largest finite number that can be represented in the
current precision, with the sign of the intermediate result. For
round-ceiling, the result is the same as for round-down if the sign of
the intermediate result is 1, or is [0,inf] otherwise. For round-floor,
the result is the same as for round-down if the sign of the intermediate
result is 0, or is [1,inf] otherwise. In all cases, Inexact and Rounded
will also be raised.
|
| |
- Method resolution order:
- Overflow
- Inexact
- Rounded
- DecimalException
- exceptions.ArithmeticError
- exceptions.StandardError
- exceptions.Exception
- exceptions.BaseException
- __builtin__.object
Methods defined here:
- handle(self, context, sign, *args)
Data descriptors inherited from DecimalException:
- __weakref__
- list of weak references to the object (if defined)
Methods inherited from exceptions.ArithmeticError:
- __init__(...)
- x.__init__(...) initializes x; see help(type(x)) for signature
Data and other attributes inherited from exceptions.ArithmeticError:
- __new__ = <built-in method __new__ of type object>
- T.__new__(S, ...) -> a new object with type S, a subtype of T
Methods inherited from exceptions.BaseException:
- __delattr__(...)
- x.__delattr__('name') <==> del x.name
- __getattribute__(...)
- x.__getattribute__('name') <==> x.name
- __getitem__(...)
- x.__getitem__(y) <==> x[y]
- __getslice__(...)
- x.__getslice__(i, j) <==> x[i:j]
Use of negative indices is not supported.
- __reduce__(...)
- __repr__(...)
- x.__repr__() <==> repr(x)
- __setattr__(...)
- x.__setattr__('name', value) <==> x.name = value
- __setstate__(...)
- __str__(...)
- x.__str__() <==> str(x)
- __unicode__(...)
Data descriptors inherited from exceptions.BaseException:
- __dict__
- args
- message
|
class Underflow(Inexact, Rounded, Subnormal) |
| |
Numerical underflow with result rounded to 0.
This occurs and signals underflow if a result is inexact and the
adjusted exponent of the result would be smaller (more negative) than
the smallest value that can be handled by the implementation (the value
Emin). That is, the result is both inexact and subnormal.
The result after an underflow will be a subnormal number rounded, if
necessary, so that its exponent is not less than Etiny. This may result
in 0 with the sign of the intermediate result and an exponent of Etiny.
In all cases, Inexact, Rounded, and Subnormal will also be raised.
|
| |
- Method resolution order:
- Underflow
- Inexact
- Rounded
- Subnormal
- DecimalException
- exceptions.ArithmeticError
- exceptions.StandardError
- exceptions.Exception
- exceptions.BaseException
- __builtin__.object
Methods inherited from DecimalException:
- handle(self, context, *args)
Data descriptors inherited from DecimalException:
- __weakref__
- list of weak references to the object (if defined)
Methods inherited from exceptions.ArithmeticError:
- __init__(...)
- x.__init__(...) initializes x; see help(type(x)) for signature
Data and other attributes inherited from exceptions.ArithmeticError:
- __new__ = <built-in method __new__ of type object>
- T.__new__(S, ...) -> a new object with type S, a subtype of T
Methods inherited from exceptions.BaseException:
- __delattr__(...)
- x.__delattr__('name') <==> del x.name
- __getattribute__(...)
- x.__getattribute__('name') <==> x.name
- __getitem__(...)
- x.__getitem__(y) <==> x[y]
- __getslice__(...)
- x.__getslice__(i, j) <==> x[i:j]
Use of negative indices is not supported.
- __reduce__(...)
- __repr__(...)
- x.__repr__() <==> repr(x)
- __setattr__(...)
- x.__setattr__('name', value) <==> x.name = value
- __setstate__(...)
- __str__(...)
- x.__str__() <==> str(x)
- __unicode__(...)
Data descriptors inherited from exceptions.BaseException:
- __dict__
- args
- message
| |