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

Diagnosing machine 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

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


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


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, subtracted 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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