1. sigma(nphase,3) (double complex) Values of the diagonal elements of the conductivity tensor for each phase (conductivity tensor is diagonal only). 1,2,3 = x,y,z, respectively.
2. ex,ey,ez (double precision): Components of applied field, E = (ex, ey, ez).
3. nfreq (integer*4) : Indicates how many frequencies are to be used at which to compute the complex conductivity. The program was originally set up to simulate the experimental probe of impedance spectroscopy, which scans a sample over a number of frequencies of applied electrical signal. In the numerical code, one often desires to scan over a similar set of frequencies. When doing so, the program converges better if the complex voltages from the last computation are used for the initial voltage values for the next frequency computation. When the frequencies are close, like they usually are in a sweep, this works well and save an appreciable amount of computer time. If the frequencies are far apart, there is little benefit to this procedure, and one might as well use a uniform field initial condition at all frequencies.4. ncheck (integer*4) : Subroutine DEMBX_AC will write out the total current and norm of the gradient squared every ncheck gradient steps.