Department of Computer Science and Engineering, University of California, San Diego, USA. bandeira@ucsd.edu|Department of Computer Science and Engineering, University of California, San Diego, USA. bandeira@ucsd.edu|Department of Computer Science and Engineering, University of California, San Diego, USA. bandeira@ucsd.edu|Department of Computer Science and Engineering, University of California, San Diego, USA. bandeira@ucsd.edu|Department of Computer Science and Engineering, University of California, San Diego, USA. bandeira@ucsd.edu