Testing Rank of Incomplete Unimodal Matrices

Several statistics-based detectors, based on unimodal matrix models, for determining the number of sources in a field are designed. A new variance-ratio statistic is proposed, and its asymptotic distribution is analyzed. The variance-ratio detector is shown to outperform the alternatives. It is shown that further improvements are achievable via optimally selected rotations. Numerical experiments demonstrate the performance gains of our detection methods over the baseline approach.