def arctan2(x1, x2, *args, **kwargs):
"""
arctan2(x1, x2, /, out=None, *, where=True, casting='same_kind', order='K', dtype=None, subok=True[, signature, extobj])
Element-wise arc tangent of ``x1/x2`` choosing the quadrant correctly.
元素方面的``X1 / x2``正确地选择象限反正切。
The quadrant (i.e., branch) is chosen so that ``arctan2(x1, x2)`` is
the signed angle in radians between the ray ending at the origin and
passing through the point (1,0), and the ray ending at the origin and
passing through the point (`x2`, `x1`). (Note the role reversal: the
"`y`-coordinate" is the first function parameter, the "`x`-coordinate"
is the second.) By IEEE convention, this function is defined for
`x2` = +/-0 and for either or both of `x1` and `x2` = +/-inf (see
Notes for specific values).
选择象限（即分支），以使“ arctan2（x1，x2）”是从原点结束并通过点（1,0）的射线与在结束点的射线之间的弧度的符号角 原点并经过点（`x2`，`x1`）。 （请注意角色反转：“ y”坐标是第一个函数参数，“ x”坐标是第二个函数参数。）按照IEEE惯例，此函数定义为“ x2” = +/- 0 并且对于“ x1”和“ x2”中的一个或两个都= +/- inf（有关具体值，请参见注释）。
This function is not defined for complex-valued arguments; for the
so-called argument of complex values, use `angle`.
没有为复数值参数定义此函数； 对于所谓的复数值参数，请使用“ angle”。
Parameters
----------
x1 : array_like, real-valued
`y`-coordinates.y坐标。
x2 : array_like, real-valued
`x`-coordinates. `x2` must be broadcastable to match the shape of
`x1` or vice versa.
x坐标。 x2必须是可广播的，以匹配x1的形状，反之亦然。
out : ndarray, None, or tuple of ndarray and None, optional
A location into which the result is stored. If provided, it must have
a shape that the inputs broadcast to. If not provided or `None`,
a freshly-allocated array is returned. A tuple (possible only as a
keyword argument) must have length equal to the number of outputs.
结果存储的位置。 如果提供，它必须具有输入广播到的形状。 如果未提供或“无”，则返回一个新分配的数组。 元组（只能作为关键字参数）的长度必须等于输出的数量。
where : array_like, optional
Values of True indicate to calculate the ufunc at that position, values
of False indicate to leave the value in the output alone.
值为True表示要在该位置计算ufunc，值为False表示将值保留在输出中。
**kwargs
For other keyword-only arguments, see the
:ref:`ufunc docs `.
Returns
-------
angle : ndarray
Array of angles in radians, in the range ``[-pi, pi]``.
This is a scalar if both `x1` and `x2` are scalars.
弧度的角度数组，范围为“ [-pi，pi]”。
如果x1和x2均为标量，则为标量。
See Also
--------
arctan, tan, angle
Notes
-----
*arctan2* is identical to the `atan2` function of the underlying
C library. The following special values are defined in the C
standard: [1]_
* arctan2 *与基础C库的`atan2`函数相同。 在C标准中定义了以下特殊值：[1] _
====== ====== ================
`x1` `x2` `arctan2(x1,x2)`
====== ====== ================
+/- 0 +0 +/- 0
+/- 0 -0 +/- pi
> 0 +/-inf +0 / +pi
< 0 +/-inf -0 / -pi
+/-inf +inf +/- (pi/4)
+/-inf -inf +/- (3*pi/4)
====== ====== ================
Note that +0 and -0 are distinct floating point numbers, as are +inf
and -inf.
请注意，+ 0和-0是不同的浮点数，+ inf和-inf也是如此。
References
----------
.. [1] ISO/IEC standard 9899:1999, "Programming language C."
Examples
--------
Consider four points in different quadrants:
考虑不同象限中的四个点
>>> x = np.array([-1, +1, +1, -1])
>>> y = np.array([-1, -1, +1, +1])
>>> np.arctan2(y, x) * 180 / np.pi
array([-135., -45., 45., 135.])
Note the order of the parameters. `arctan2` is defined also when `x2` = 0
and at several other special points, obtaining values in
the range ``[-pi, pi]``:
注意参数的顺序。 当`x2` = 0且在其他几个特殊点时，也定义了`arctan2`，获得的值在[-pi，pi]范围内：
>>> np.arctan2([1., -1.], [0., 0.])
array([ 1.57079633, -1.57079633])
>>> np.arctan2([0., 0., np.inf], [+0., -0., np.inf])
array([ 0. , 3.14159265, 0.78539816])
"""
pass
