bladex.ndinterpolator.RBF.inv_multi_quadratic_biharmonic_spline

static RBF.inv_multi_quadratic_biharmonic_spline(X, r)[source]

It implements the following formula:

\varphi(\| \boldsymbol{x} \|) =
(\| \boldsymbol{x} \|^2 + r^2 )^{-\frac{1}{2}}

Parameters:
  • X (numpy.ndarray) – l2-norm between given inputs of a function and the locations to perform rbf approximation to that function.
  • r (float) – smoothing length, also called the cut-off radius.
Returns:

result: the result of the formula above.

Return type:

float