Function guff_ida::cauchy_inverse_matrix

pub fn cauchy_inverse_matrix<G>(
    field: &G, 
    key: &Vec<G::E>, 
    k: usize
) -> Vec<G::E> where
    G: GaloisField, 

Generate inverse Cauchy matrix using a key

If the “key” used to generate the forward Cauchy matrix is saved, it can be used to calculate the inverse more efficiently than doing full Gaussian elimination.

See:

• https://en.wikipedia.org/wiki/Cauchy_matrix
• https://proofwiki.org/wiki/Inverse_of_Cauchy_Matrix

Note that the inverse is a k*k matrix, so 2*k distinct values must be passed in:

• the fixed y1 .. yk values
• a selection of k x values corresponding to the k rows being combined