“…Examples include scientific computing and numerical optimization [8,13,26], graph partitioning and data clustering [15,22], machine learning and data mining [6,14], as well as integrated circuit modeling, simulation and verifications [11,29,30]. In particular, latest theoretical breakthroughs in spectral graph theory have led to the development of nearly-linear time spectral graph sparsification [8,9,16,25] and coarsening algorithms [18,19,31,33]. These techniques can efficiently produce much smaller graphs that well preserve the key spectral properties of the original graph (e.g., the first few eigenvalues and eigenvectors of the graph Laplacian), which in turn has led to much faster algorithms for solving partial differential equations (PDEs) and linear systems of equations [21,25,32], spectral clustering and graph partitioning [9,15,22,31], and dimensionality reduction and data visualization [33].…”