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# numpy.sqrt

`numpy.``sqrt`(x[, out])

  Return the positive square-root of an array, element-wise.

  Parameters: | x : array_like The square root of each element in this array is calculated.
  Returns: | y : ndarray An array of the same shape as x, containing the square-root of each element in x. If any element in x is complex, a complex array is returned. If all of the elements of x are real, negative elements return numpy.nan elements.

  See also

  `numpy.lib.scimath.sqrt`
    A version which returns complex numbers when given negative reals.

  Notes

  sqrt has a branch cut `[-inf, 0)` and is continuous from above on it.

  Examples

      >>> 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])

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