Find 8 coeff mentioned [here](https://web.archive.org/web/20150222120106/xenia.media.mit.edu/~cwren/interpolator/).

def _find_coeffs(orig_pts:Points, targ_pts:Points)->Tensor:
    "Find 8 coeff mentioned [here](https://web.archive.org/web/20150222120106/xenia.media.mit.edu/~cwren/interpolator/)."
    matrix = []
    #The equations we'll need to solve.
    for p1, p2 in zip(targ_pts, orig_pts):
        matrix.append([p1[0], p1[1], 1, 0, 0, 0, -p2[0]*p1[0], -p2[0]*p1[1]])
        matrix.append([0, 0, 0, p1[0], p1[1], 1, -p2[1]*p1[0], -p2[1]*p1[1]])

    A = FloatTensor(matrix)
    B = FloatTensor(orig_pts).view(8, 1)
    #The 8 scalars we seek are solution of AX = B
    return _solve_func(B,A)[0][:,0]