SciPy

numpy.MachAr

class numpy.MachAr(float_conv=<type 'float'>, int_conv=<type 'int'>, float_to_float=<type 'float'>, float_to_str=<function <lambda> at 0x7f63b6221de8>, title='Python floating point number')[source]

Diagnosing machine parameters.

Parameters:

float_conv : function, optional

Function that converts an integer or integer array to a float or float array. Default is float.

int_conv : function, optional

Function that converts a float or float array to an integer or integer array. Default is int.

float_to_float : function, optional

Function that converts a float array to float. Default is float. Note that this does not seem to do anything useful in the current implementation.

float_to_str : function, optional

Function that converts a single float to a string. Default is lambda v:'%24.16e' %v.

title : str, optional

Title that is printed in the string representation of MachAr.

See also

finfo
Machine limits for floating point types.
iinfo
Machine limits for integer types.

References

[R1]Press, Teukolsky, Vetterling and Flannery, “Numerical Recipes in C++,” 2nd ed, Cambridge University Press, 2002, p. 31.

Attributes

ibeta int Radix in which numbers are represented.
it int Number of base-ibeta digits in the floating point mantissa M.
machep int Exponent of the smallest (most negative) power of ibeta that, added to 1.0, gives something different from 1.0
eps float Floating-point number beta**machep (floating point precision)
negep int Exponent of the smallest power of ibeta that, substracted from 1.0, gives something different from 1.0.
epsneg float Floating-point number beta**negep.
iexp int Number of bits in the exponent (including its sign and bias).
minexp int Smallest (most negative) power of ibeta consistent with there being no leading zeros in the mantissa.
xmin float Floating point number beta**minexp (the smallest [in magnitude] usable floating value).
maxexp int Smallest (positive) power of ibeta that causes overflow.
xmax float (1-epsneg) * beta**maxexp (the largest [in magnitude] usable floating value).
irnd int In range(6), information on what kind of rounding is done in addition, and on how underflow is handled.
ngrd int Number of ‘guard digits’ used when truncating the product of two mantissas to fit the representation.
epsilon float Same as eps.
tiny float Same as xmin.
huge float Same as xmax.
precision float - int(-log10(eps))
resolution float - 10**(-precision)

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