public static

Returns the angle *theta* from the conversion of rectangular
coordinates (` x`

, ` y`

) to polar
coordinates (r, *theta*).
This method computes the phase *theta* by computing an arc tangent
of ` y/x`

in the range of -*pi* to *pi*. Special
cases:

- If either argument is NaN, then the result is NaN.
- If the first argument is positive zero and the second argument is positive, or the first argument is positive and finite and the second argument is positive infinity, then the result is positive zero.
- If the first argument is negative zero and the second argument is positive, or the first argument is negative and finite and the second argument is positive infinity, then the result is negative zero.
- If the first argument is positive zero and the second argument
is negative, or the first argument is positive and finite and the
second argument is negative infinity, then the result is the
`double`

value closest to*pi*. - If the first argument is negative zero and the second argument
is negative, or the first argument is negative and finite and the
second argument is negative infinity, then the result is the
`double`

value closest to -*pi*. - If the first argument is positive and the second argument is
positive zero or negative zero, or the first argument is positive
infinity and the second argument is finite, then the result is the
`double`

value closest to*pi*/2. - If the first argument is negative and the second argument is
positive zero or negative zero, or the first argument is negative
infinity and the second argument is finite, then the result is the
`double`

value closest to -*pi*/2. - If both arguments are positive infinity, then the result is the
`double`

value closest to*pi*/4. - If the first argument is positive infinity and the second argument
is negative infinity, then the result is the
`double`

value closest to 3**pi*/4. - If the first argument is negative infinity and the second argument
is positive infinity, then the result is the
`double`

value closest to -*pi*/4. - If both arguments are negative infinity, then the result is the
`double`

value closest to -3**pi*/4.

The computed result must be within 2 ulps of the exact result. Results must be semi-monotonic.

`y` | the ordinate coordinate | |

`x` | the abscissa coordinate |

*theta* component of the point
(*r*, *theta*)
in polar coordinates that corresponds to the point
(*x*, *y*) in Cartesian coordinates.

Diagram: Math