Hello all,

Assume NxN matrix A of complex values. I want to calculate the sum of all elements of its inverse.

The problem is that calculating the inverse is computationally expensive and since I am looking only for the sum of its elements, I thought there might be something smarter to do.

Note: the real part of A is a diagonal matrix while the imaginary is a 2x2 block matrix of symmetric submatrices.

Thank you