skrf.mathFunctions.cross_ratio¶
- skrf.mathFunctions.cross_ratio(a, b, c, d)[source]¶
Calculate the cross ratio of a quadruple of distinct points on the real line.
The cross ratio is defined as:
\[r = \frac{ (a-b)(c-d) }{ (a-d)(c-b) }\]- Parameters
a (array-like or number) –
b (array-like or number) –
c (array-like or number) –
d (array-like or number) –
- Returns
r
- Return type
array-like or number
References