A multilevel implementation of the QR compression for method of moments

We present a multilevel version of a previously reported compression technique for the method of moments (Poirier, J.-R. et al., ibid., vol.46, p.1175-6, 1998). This method is based on QR compression of the impedance matrix off-diagonal blocks. The block structure of the matrix is built up to optimize the compression rate. It results from the study that the compression threshold is the unique adjustment parameter, which makes this method very easy to handle. Some results are presented, which stress the improvement in memory storage and computation time obtained through this approach with respect to the mono-level algorithm.