Function Vpi

ot/dr.py:373–381

(X, Y, a, b, pi)

        U = U0

    def Vpi(X, Y, a, b, pi):
        # Return the second order matrix of the displacements: sum_ij { (pi)_ij (X_i-Y_j)(X_i-Y_j)^T }.
        A = X.T.dot(pi).dot(Y)
        return (
            X.T.dot(np.diag(a)).dot(X)
            + Y.T.dot(np.diag(np.sum(pi, 0))).dot(Y)
            - A
            - A.T
        )

    err = 1
    iter = 0