The total field of influence calculates the sum of all first order field of influences:
$$F^{total} = \sum_i \sum_j F_{i,j}$$
where
$$F_{i, j} = L_{.j} L_{i.}$$
such that \(L_{.j}\) is the jth column of the Leontief inverse and \(L_{i.}\) is the ith row of the Leontief inverse.