numpy.ldexp

numpy.ldexp(x1, x2[, out]) = <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, optional

Output array for the result.

Returns:

y : ndarray or scalar

The result of x1 * 2**x2.

See also

frexp

Return (y1, y2) from x = y1 * 2**y2, inverse to ldexp.

Notes

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.

Examples

>>> 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.])