20,425 research outputs found
Multi-Agent Distributed Optimization via Inexact Consensus ADMM
Multi-agent distributed consensus optimization problems arise in many signal
processing applications. Recently, the alternating direction method of
multipliers (ADMM) has been used for solving this family of problems. ADMM
based distributed optimization method is shown to have faster convergence rate
compared with classic methods based on consensus subgradient, but can be
computationally expensive, especially for problems with complicated structures
or large dimensions. In this paper, we propose low-complexity algorithms that
can reduce the overall computational cost of consensus ADMM by an order of
magnitude for certain large-scale problems. Central to the proposed algorithms
is the use of an inexact step for each ADMM update, which enables the agents to
perform cheap computation at each iteration. Our convergence analyses show that
the proposed methods converge well under some convexity assumptions. Numerical
results show that the proposed algorithms offer considerably lower
computational complexity than the standard ADMM based distributed optimization
methods.Comment: submitted to IEEE Trans. Signal Processing; Revised April 2014 and
August 201
Asynchronous Distributed ADMM for Large-Scale Optimization- Part I: Algorithm and Convergence Analysis
Aiming at solving large-scale learning problems, this paper studies
distributed optimization methods based on the alternating direction method of
multipliers (ADMM). By formulating the learning problem as a consensus problem,
the ADMM can be used to solve the consensus problem in a fully parallel fashion
over a computer network with a star topology. However, traditional synchronized
computation does not scale well with the problem size, as the speed of the
algorithm is limited by the slowest workers. This is particularly true in a
heterogeneous network where the computing nodes experience different
computation and communication delays. In this paper, we propose an asynchronous
distributed ADMM (AD-AMM) which can effectively improve the time efficiency of
distributed optimization. Our main interest lies in analyzing the convergence
conditions of the AD-ADMM, under the popular partially asynchronous model,
which is defined based on a maximum tolerable delay of the network.
Specifically, by considering general and possibly non-convex cost functions, we
show that the AD-ADMM is guaranteed to converge to the set of
Karush-Kuhn-Tucker (KKT) points as long as the algorithm parameters are chosen
appropriately according to the network delay. We further illustrate that the
asynchrony of the ADMM has to be handled with care, as slightly modifying the
implementation of the AD-ADMM can jeopardize the algorithm convergence, even
under a standard convex setting.Comment: 37 page
Semileptonic Decays of Meson to a P-Wave Charmonium State or
The semileptonic decays of meson to a P-wave charmonium state
or are computed. The results show that the decays
are sizable so they are accessible in Tevatron and in LHC, especially, with the
detectors LHCB and BTeV in the foreseeable future, and of them, the one to the
charmonium state potentially offers us a novel window to see the
unconfirmed particle. In addition, it is pointed out that since the two
charmonium radiative decays have sizable
branching ratios, the cascade decays of the concerned decays and the charmonium
radiative decays may affect the result of the observing the meson through
the semileptonic decays substantially.Comment: 8 pages, 2 figure
- …