numpy.frexp()

numpy.frexp(x[, out1, out2]) =

Decompose the elements of x into mantissa and twos exponent.

Returns (mantissa, exponent), where x = mantissa * 2**exponent`. The mantissa is lies in the open interval(-1, 1), while the twos exponent is a signed integer.

Parameters:

Parameters:	x : array_like Array of numbers to be decomposed. out1 : ndarray, optional Output array for the mantissa. Must have the same shape as `x`. out2 : ndarray, optional Output array for the exponent. Must have the same shape as `x`.
Returns:	(mantissa, exponent) : tuple of ndarrays, (float, int) `mantissa` is a float array with values between -1 and 1. `exponent` is an int array which represents the exponent of 2.

x : array_like

Array of numbers to be decomposed.

out1 : ndarray, optional

Output array for the mantissa. Must have the same shape as x.

out2 : ndarray, optional

Output array for the exponent. Must have the same shape as x.

Returns:

(mantissa, exponent) : tuple of ndarrays, (float, int)

mantissa is a float array with values between -1 and 1. exponent is an int array which represents the exponent of 2.

Notes

Complex dtypes are not supported, they will raise a TypeError.

Examples

>>> x = np.arange(9)
>>> y1, y2 = np.frexp(x)
>>> y1
array([ 0.   ,  0.5  ,  0.5  ,  0.75 ,  0.5  ,  0.625,  0.75 ,  0.875,
        0.5  ])
>>> y2
array([0, 1, 2, 2, 3, 3, 3, 3, 4])
>>> y1 * 2**y2
array([ 0.,  1.,  2.,  3.,  4.,  5.,  6.,  7.,  8.])

Links:

https://docs.scipy.org/doc/numpy-1.11.0/reference/generated/numpy.frexp.html

doc_NumPy

2017-01-10 18:14:07

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