In a recent work [3] the authors improved one of the most efficient interior-point approaches for some classes of block-angular problems. This was achieved by adding a quadratic regularization to the logarithmic barrier. This regularized barrier was shown to be self-concordant, thus fitting the general structural optimization interior-point framework. In practice, however, most codes implement ...

Program profiling can help performance prediction and compiler optimization. This paper describes the initial work behind TFP, a new profiling strategy that can gather and verify a range of flow-specific information at runtime. While TFP can collect more refined information than block, edge or path profiling, it is only 5.75% slower than a very fast runtime path-profiling technique. Statistics ...

A digraph D = (V, A) is arc-traceable if for each arc xy in A, xy lies on a directed path containing all the vertices of V , i.e., hamiltonian path. We prove a conjecture of Quintas [7]: if D is arc-traceable, then the condensation of D is a directed path. We show that the converse of this conjecture is false by providing an example of an upset tournament which is not arc-traceable. We then giv...

2.2 Distance between Two Vertices The distance between two vertices u and v is defined as the length of the shortest path connecting them. Remark 1. The number of paths connecting two vertices could be exponential. As shown in the below illustration, there are around 3 ”blocks” to choose from given that there are n vertices in total and each block takes around 3 vertices. The number of paths av...

Multiple-block prediction is emerging as a new and exciting research area. Highly accurate multiple-block predictors are essential for wide instruction fetch mechanisms, that will support future generations of microprocessors. The block-based trace cache is a recent proposal for wide instruction fetch. It aligns and stores instructions at the basic block level instead of at the trace level, thu...

Headphones with feedback Active Noise Control (ANC) have some advantages over feedforward applications [1], but suffer from the risk of instabilities. A block diagram of a typical digital feedback ANC headphone (compare [1], [2]) is shown in Fig. 1. The performance and stability of this system depends on the modelling accuracy of the secondary path (i.e. the transfer function from the loudspeak...

We present a parallel algorithm for computing an equilibrium path in a large-scale economic growth model. We exploit the special block structure of the nonlinear systems of equations common in such models. Our algorithm is based on an iterative method of Gauss-Seidel type with prices of different time periods calculated simultaneously rather than recursively. We have implemented the parallel al...

In this paper we present the convergence analysis of the inexact infeasible path-following (IIPF) interior point algorithm. In this algorithm the preconditioned conjugate gradient method is used to solve the reduced KKT system (the augmented system). The augmented system is preconditioned by using a block triangular matrix. The KKT system is solved approximately. Therefore, it becomes necessary...

A Lagrangian flow network is constructed for the atmospheric blocking of Eastern Europe and Western Russia in summer 2010. We compute the most probable paths followed by fluid particles, which reveal the Omega-block skeleton of the event. A hierarchy of sets of highly probable paths is introduced to describe transport pathways when the most probable path alone is not representative enough. Thes...