numpy.real_if_close#

numpy.real_if_close(a, tol=100)[source]#

If input is complex with all imaginary parts close to zero, return real parts.

Close to zero is defined as tol * (machine epsilon of the type for a).

Parameters:

aarray_like

Input array.

tolfloat

Tolerance in machine epsilons for the complex part of the elements in the array. If the tolerance is <=1, then the absolute tolerance is used.

Returns:

outndarray

If a is real, the type of a is used for the output. If a has complex elements, the returned type is float.

See also

real, imag, angle

Notes

Machine epsilon varies from machine to machine and between data types but Python floats on most platforms have a machine epsilon equal to 2.2204460492503131e-16. You can use np.finfo(float).eps to print out the machine epsilon for floats.

Examples

Try it in your browser!

>>> import numpy as np
>>> np.finfo(float).eps
2.2204460492503131e-16 # may vary

>>> np.real_if_close([2.1 + 4e-14j, 5.2 + 3e-15j], tol=1000)
array([2.1, 5.2])
>>> np.real_if_close([2.1 + 4e-13j, 5.2 + 3e-15j], tol=1000)
array([2.1+4.e-13j, 5.2 + 3e-15j])

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