Expression of Concern: FastMag: a 3-D magnetostatic inductance extraction program for structures with permeable materials

In this paper we present a fast and efficient program for extraction of the frequency dependent inductance of structures with permeable materials. The program, FastMag, uses a magnetic surface charge formulation, efficient techniques for evaluating the required integrals, and a preconditioned GMRES (generalized minimal residual algorithm) method to solve the resulting linear system. Results from examples are presented to demonstrate the accuracy and versatility of the FastMag program.