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""" Machine limits for Float32 and Float64 and (long double) if available...
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__all__ = ['finfo','iinfo']
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from machar import MachAr
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import numerictypes as ntypes
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from numeric import array
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"""fix rank-0 --> rank-1"""
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if a.ndim == 0: a.shape = (1,)
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ntypes.csingle: ntypes.single,
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ntypes.complex_: ntypes.float_,
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ntypes.clongfloat: ntypes.longfloat
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Machine limits for floating point types.
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eps : floating point number of the appropriate type
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The smallest representable number such that ``1.0 + eps != 1.0``.
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epsneg : floating point number of the appropriate type
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The smallest representable number such that ``1.0 - epsneg != 1.0``.
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The number of bits in the exponent portion of the floating point
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The object which calculated these parameters and holds more detailed
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The exponent that yields ``eps``.
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max : floating point number of the appropriate type
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The largest representable number.
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The smallest positive power of the base (2) that causes overflow.
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min : floating point number of the appropriate type
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The smallest representable number, typically ``-max``.
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The most negative power of the base (2) consistent with there being
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no leading 0's in the mantissa.
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The exponent that yields ``epsneg``.
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The number of bits in the exponent including its sign and bias.
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The number of bits in the mantissa.
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The approximate number of decimal digits to which this kind of float
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resolution : floating point number of the appropriate type
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The approximate decimal resolution of this type, i.e.
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tiny : floating point number of the appropriate type
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The smallest-magnitude usable number.
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dtype : floating point type, dtype, or instance
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The kind of floating point data type to get information about.
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MachAr : The implementation of the tests that produce this information.
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iinfo : The equivalent for integer data types.
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For developers of NumPy: do not instantiate this at the module level. The
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initial calculation of these parameters is expensive and negatively impacts
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import times. These objects are cached, so calling ``finfo()`` repeatedly
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inside your functions is not a problem.
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def __new__(cls, dtype):
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dtype = numeric.dtype(dtype)
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# In case a float instance was given
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dtype = numeric.dtype(type(dtype))
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obj = cls._finfo_cache.get(dtype,None)
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newdtype = numeric.obj2sctype(dtype)
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if newdtype is not dtype:
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dtypes.append(newdtype)
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if not issubclass(dtype, numeric.inexact):
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raise ValueError, "data type %r not inexact" % (dtype)
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obj = cls._finfo_cache.get(dtype,None)
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if not issubclass(dtype, numeric.floating):
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newdtype = _convert_to_float[dtype]
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if newdtype is not dtype:
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dtypes.append(newdtype)
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obj = cls._finfo_cache.get(dtype,None)
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obj = object.__new__(cls)._init(dtype)
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cls._finfo_cache[dt] = obj
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def _init(self, dtype):
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self.dtype = numeric.dtype(dtype)
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if dtype is ntypes.double:
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elif dtype is ntypes.single:
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elif dtype is ntypes.longdouble:
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itype = ntypes.longlong
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precname = 'long double'
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raise ValueError, repr(dtype)
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machar = MachAr(lambda v:array([v], dtype),
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lambda v:_frz(v.astype(itype))[0],
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lambda v:array(_frz(v)[0], dtype),
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lambda v: fmt % array(_frz(v)[0], dtype),
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'numpy %s precision floating point number' % precname)
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for word in ['precision', 'iexp',
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'maxexp','minexp','negep',
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setattr(self,word,getattr(machar, word))
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for word in ['tiny','resolution','epsneg']:
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setattr(self,word,getattr(machar, word).squeeze())
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self.max = machar.huge.flat[0]
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self.eps = machar.eps.flat[0]
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self.nexp = machar.iexp
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self.nmant = machar.it
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self._str_tiny = machar._str_xmin.strip()
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self._str_max = machar._str_xmax.strip()
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self._str_epsneg = machar._str_epsneg.strip()
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self._str_eps = machar._str_eps.strip()
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self._str_resolution = machar._str_resolution.strip()
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Machine parameters for %(dtype)s
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---------------------------------------------------------------------
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precision=%(precision)3s resolution= %(_str_resolution)s
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machep=%(machep)6s eps= %(_str_eps)s
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negep =%(negep)6s epsneg= %(_str_epsneg)s
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minexp=%(minexp)6s tiny= %(_str_tiny)s
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maxexp=%(maxexp)6s max= %(_str_max)s
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nexp =%(nexp)6s min= -max
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---------------------------------------------------------------------
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Machine limits for integer types.
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The smallest integer expressible by the type.
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The largest integer expressible by the type.
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type : integer type, dtype, or instance
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The kind of integer data type to get information about.
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finfo : The equivalent for floating point data types.
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>>> ii16 = np.iinfo(np.int16)
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>>> ii32 = np.iinfo(np.int32)
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>>> ii32 = np.iinfo(np.int32(10))
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def __init__(self, int_type):
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self.dtype = numeric.dtype(int_type)
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self.dtype = numeric.dtype(type(int_type))
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self.kind = self.dtype.kind
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self.bits = self.dtype.itemsize * 8
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self.key = "%s%d" % (self.kind, self.bits)
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if not self.kind in 'iu':
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raise ValueError("Invalid integer data type.")
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"""Minimum value of given dtype."""
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val = iinfo._min_vals[self.key]
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val = int(-(1L << (self.bits-1)))
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iinfo._min_vals[self.key] = val
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"""Maximum value of given dtype."""
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val = iinfo._max_vals[self.key]
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val = int((1L << self.bits) - 1)
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val = int((1L << (self.bits-1)) - 1)
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iinfo._max_vals[self.key] = val
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"""String representation."""
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Machine parameters for %(dtype)s
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---------------------------------------------------------------------
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---------------------------------------------------------------------
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''' % {'dtype': self.dtype, 'min': self.min, 'max': self.max}
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if __name__ == '__main__':
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f = finfo(ntypes.single)
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print 'single epsilon:',f.eps
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print 'single tiny:',f.tiny
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f = finfo(ntypes.float)
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print 'float epsilon:',f.eps
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print 'float tiny:',f.tiny
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f = finfo(ntypes.longfloat)
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print 'longfloat epsilon:',f.eps
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print 'longfloat tiny:',f.tiny
added
removed
numpy/core/getlimits.py
