Detector.surface_normal

Detector.surface_normal(param)

Unit vector perpendicular to the detector surface at param.

The orientation is chosen as follows:

• In 2D, the system (normal, tangent) should be right-handed.

• In 3D, the system (tangent[0], tangent[1], normal) should be right-handed.

Here, tangent is the return value of surface_deriv at param.

Parameters:

paramarray-like or sequence

Parameter value(s) at which to evaluate. If ndim >= 2, a sequence of length ndim must be provided.

Returns:

normalnumpy.ndarray

Unit vector(s) perpendicular to the detector surface at param. If param is a single parameter, an array of shape (space_ndim,) representing a single vector is returned. Otherwise the shape of the returned array is

• param.shape + (space_ndim,) if ndim is 1,

• param.shape[:-1] + (space_ndim,) otherwise.