numpy.ldexp(x1, x2, /, out=None, *, where=True, casting='same_kind', order='K', dtype=None, subok=True[, signature, extobj]) = <ufunc 'ldexp'>
Returns x1 * 2**x2, element-wise.
The mantissas x1
and twos exponents x2
are used to construct floating point numbers x1 * 2**x2
.
Parameters: |
x1 : array_like Array of multipliers. x2 : array_like, int Array of twos exponents. out : ndarray, None, or tuple of ndarray and None, optional A location into which the result is stored. If provided, it must have a shape that the inputs broadcast to. If not provided or where : array_like, optional Values of True indicate to calculate the ufunc at that position, values of False indicate to leave the value in the output alone. **kwargs For other keyword-only arguments, see the ufunc docs. |
---|---|
Returns: |
y : ndarray or scalar The result of |
Complex dtypes are not supported, they will raise a TypeError.
ldexp
is useful as the inverse of frexp
, if used by itself it is more clear to simply use the expression x1 * 2**x2
.
>>> np.ldexp(5, np.arange(4)) array([ 5., 10., 20., 40.], dtype=float32)
>>> x = np.arange(6) >>> np.ldexp(*np.frexp(x)) array([ 0., 1., 2., 3., 4., 5.])
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https://docs.scipy.org/doc/numpy-1.14.2/reference/generated/numpy.ldexp.html