megengine.functional.atan2#

atan2(y, x)[source]#

Element-wise \(\arctan(\frac{y}{x})\) function.

Calculates an approximation to the inverse tangent for each element \(x_i\) of the input tensor \(x\) with the respective element \(y_i\) of the input tensor \(y\).

Parameters:

  • y – first input tensor whose elements correspond to the dividend. Should have a numeric data type.

  • x – second input tensor whose elements correspond to the divisor. Must be compatible with x (see Broadcasting mechanism and rules ). Should have a numeric data type.

Returns:

a tensor containing the inverse tangent of each element in \(y/x\).

Special cases

atan2 is identical to the atan2 function of the underlying C library. The following special values are defined in the C standard:

For floating-point operands,

  • if \(y\) is +/-0` and \(x\) is +0, the result is +/-0.

  • if \(y\) is +/-0 and \(x\) is -0, the result is +/-π.

  • if \(y\) is greater than 0 and \(x\) is +/-infinity, the result is +0/+π.

  • if \(y\) is less than 0 and \(x\) is +/-infinity, the result is -0/-π.

  • if \(y\) is +/-infinity`and :math:`x` is ``+infinity, tge result is +/-(π/4).

  • if \(y\) is +/-infinity`and :math:`x` is ``-infinity, tge result is +/-(3π/4).

Note that +0 and -0 are distinct floating point numbers, as are +inf and -inf.

Examples

>>> F.atan2(0, 1)  # equals to atan(0)
Tensor(0.0, device=xpux:0)

Element-wise inverse tangent:

>>> y = Tensor([0, 1, -1])
>>> x = Tensor([1, 1, 1])
>>> F.atan2(y, x)
Tensor([ 0.      0.7854 -0.7854], device=xpux:0)