(z_r, wavelen)
return sqrt(z_r/pi*wavelen)
Calculate the waist from the rayleigh range of a gaussian beam.

    See Also
    ========

    waist2rayleigh, BeamParameter

    Examples
    ========

    >>> from sympy.physics.gaussopt import rayleigh2waist
    >>> from sympy import symbols
    >>> z_r, wavelen = symbols('z_r wavelen')
    >>> rayleigh2waist(z_r, wavelen)
    sqrt(wavelen*z_r)/sqrt(pi)
Calculate the waist from the rayleigh range of a gaussian beam.
Calculate the waist from the rayleigh range of a gaussian beam .
def rayleigh2waist(z_r, wavelen):
    """Calculate the waist from the rayleigh range of a gaussian beam.

    See Also
    ========

    waist2rayleigh, BeamParameter

    Examples
    ========

    >>> from sympy.physics.gaussopt import rayleigh2waist
    >>> from sympy import symbols
    >>> z_r, wavelen = symbols('z_r wavelen')
    >>> rayleigh2waist(z_r, wavelen)
    sqrt(wavelen*z_r)/sqrt(pi)
    """
    z_r, wavelen = map(sympify, (z_r, wavelen))
    return sqrt(z_r/pi*wavelen)
def rayleigh2waist ( z_r , wavelen ) : z_r , wavelen = map ( sympify , ( z_r , wavelen ) ) return sqrt ( z_r / pi * wavelen )