Tuomo Valkonen

Acceleration of the PDHGM on strongly convex subspaces

  • Thomas Pock
  • Tuomo Valkonen
    • Categories Applications - Science and Engineering, Convex Optimization, Generalized Convexity/Monoticity Tags , , ,

    We propose several variants of the primal-dual method due to Chambolle and Pock. Without requiring full strong convexity of the objective functions, our methods are accelerated on subspaces with strong convexity. This yields mixed rates, $O(1/N^2)$ with respect to initialisation and $O(1/N)$ with respect to the dual sequence, and the residual part of the primal … Read more

    A method for weighted projections to the positive definite cone

  • Tuomo Valkonen
    • Categories Biomedical Applications, Quadratic Programming, Semi-definite Programming Tags , , , ,

    We study the numerical solution of the problem $\min_{X \ge 0} \|BX-c\|2$, where $X$ is a symmetric square matrix, and $B$ a linear operator, such that $B^*B$ is invertible. With $\rho$ the desired fractional duality gap, we prove $O(\sqrt{m}\log\rho^{-1})$ iteration complexity for a simple primal-dual interior point method directly based on those for linear programs … Read more