sqrt(x[, out]) = <ufunc 'sqrt'>¶
Return the positive square-root of an array, element-wise.
x : array_like
The values whose square-roots are required.
out : ndarray, optional
Alternate array object in which to put the result; if provided, it must have the same shape as x
y : ndarray
An array of the same shape as x, containing the positive square-root of each element in x. If any element in x is complex, a complex array is returned (and the square-roots of negative reals are calculated). If all of the elements in x are real, so is y, with negative elements returning
nan. If out was provided, y is a reference to it.
- A version which returns complex numbers when given negative reals.
sqrt has–consistent with common convention–as its branch cut the real “interval” [-inf, 0), and is continuous from above on it. A branch cut is a curve in the complex plane across which a given complex function fails to be continuous.
>>> np.sqrt([1,4,9]) array([ 1., 2., 3.])
>>> np.sqrt([4, -1, -3+4J]) array([ 2.+0.j, 0.+1.j, 1.+2.j])
>>> np.sqrt([4, -1, numpy.inf]) array([ 2., NaN, Inf])