PVM (the current version 3.4) as well as many current MPI implementations force application programmers to use active polling (also known as busy waiting) in larger parallel programs. This serious problem is related to thread-unsafety of these communication libraries. While the MPI specification is very careful in this respect, the implementations are not. We present a new mechanism of interrup...

OBJECTIVE To determine the association of prolonged ST segment depression after an exercise test with severity of coronary artery disease. METHODS A cross sectional study of 100 consecutive patients referred to the cardiology laboratory for stress myocardial perfusion imaging (MPI) conducted between April-August 2008. All selected patients were monitored until their ST segment depression was ...

Exascale targeted scientific applications must be prepared for a highly concurrent computing environment where failure will be a regular event during execution. Natural and algorithm-based fault tolerance (ABFT) techniques can often manage failures more efficiently than traditional checkpoint/restart techniques alone. Central to many petascale applications is an MPI standard that lacks support ...

This paper reports the design and implementation of OpenSHMEM over MPI using new one-sided communication features in MPI3, which include not only new functions (e.g. remote atomics) but also a new memory model that is consistent with that of SHMEM. We use a new, non-collective MPI communicator creation routine to allow SHMEM collectives to use their MPI counterparts. Finally, we leverage MPI sh...

OBJECTIVES To study the clinical impact of a very high coronary artery calcium score (CAC >1000) in patients with no known coronary artery disease (CAD) and normal single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI). The secondary aim was to evaluate whether triple vessel disease would support the notion of balanced ischaemia as an underlying mechanism of false...

Two alternative dual-level parallel implementations of the Multiblock Grid Princeton Ocean Model (MGPOM) are compared in this paper. The first one combines the use of two programming paradigms: message passing with the Message Passing Interface (MPI) and shared memory with OpenMP (version called MPI-OpenMP); the second uses only OpenMP (version called OpenMP-Only). MGPOM is a multiblock grid co...

BACKGROUND Subdiaphragmatic activity can produce subdiaphragmatic-related artifacts, which can degrade the quality of myocardial perfusion imaging (MPI). OBJECTIVES We examined the impact of drinking milk, water, and lemon juice on different subdiaphragmatic-related artifacts by using (99m)Tc-sestamibi myocardial single-photon emission computed tomography (SPECT) in order to determine a feasi...

A major challenge in PDE software is the balance between user-level flexibility and performance on heterogeneous hardware. We discuss our ideas on how this challenge can be tackled, exemplarily for the DUNE framework and in particular its linear algebra and solver components. We demonstrate how the former MPI-only implementation is modified to support MPI+[CPU/GPU] threading and vectorisation. ...

In this paper, we present a threads-only implementation of MPI, called TOMPI, that allows eecient development of parallel programs on a workstation. The communication and context-switching overhead is reduced signiicantly compared to existing MPI implementations , by the use of threads and shared memory in place of UNIX processes and often sockets. Results demonstrate the scalability of TOMPI i...