viernes, 25 de septiembre de 2009

Numerical Evaluation by Models of Load and Spark Timing Effects on the In-Cylinder Heat Transfer of a SI Engine





Fixed point and Bregman iterative methods for matrix rank minimization


Abstract  The linearly constrained matrix rank minimization problem is widely applicable in many fields such as control, signal processing
and system identification. The tightest convex relaxation of this problem is the linearly constrained nuclear norm minimization.
Although the latter can be cast as a semidefinite programming problem, such an approach is computationally expensive to solve
when the matrices are large. In this paper, we propose fixed point and Bregman iterative algorithms for solving the nuclear
norm minimization problem and prove convergence of the first of these algorithms. By using a homotopy approach together with
an approximate singular value decomposition procedure, we get a very fast, robust and powerful algorithm, which we call FPCA
(Fixed Point Continuation with Approximate SVD), that can solve very large matrix rank minimization problems (the code can
be downloaded from
http://www.columbia.edu/~sm2756/FPCA.htm for non-commercial use). Our numerical results on randomly generated and real matrix completion problems demonstrate that
this algorithm is much faster and provides much better recoverability than semidefinite programming solvers such as SDPT3.
For example, our algorithm can recover 1000 × 1000 matrices of rank 50 with a relative error of 10−5 in about 3 min by sampling only 20% of the elements. We know of no other method that achieves as good recoverability. Numerical
experiments on online recommendation, DNA microarray data set and image inpainting problems demonstrate the effectiveness
of our algorithms.


  • Content Type Journal Article
  • Category Full Length Paper
  • DOI 10.1007/s10107-009-0306-5
  • Authors

    • Shiqian Ma, Columbia University Department of Industrial Engineering and Operations Research New York NY 10027 USA
    • Donald Goldfarb, Columbia University Department of Industrial Engineering and Operations Research New York NY 10027 USA
    • Lifeng Chen, Columbia University Department of Industrial Engineering and Operations Research New York NY 10027 USA