This is a generalization of the function used for MEM in the countrate case. Here we have complex numbers, and the maximization has to be done with respect to real and imaginary parts. The terms that are in common with ordinary MEM are S and the last term:
- S is the entropy, (calculated in the same way).
- the last term is just Chi-squared, with two terms,
one for the real part and one for the imaginary part of the visibility.
The details of this and how Q's maximum is determined may be found in excruciating detail in Andrew Conway's
MEMVIS: Maximum Entropy Method Using Visibilities (October 25, 2000)