ABSTRACT MPI collective operations provide a standardized interface for performing data movements within a group of processes. The e ciency of collective communication operations depends on the actual algorithm, its implementation, and the speci c communication problem (type of communication, message size, number of processes). Many MPI libraries provide numerous algorithms for speci c collecti...

The Message Passing Interface (MPI) standard provides a powerful mechanism for describing non-contiguous memory locations: derived datatypes. In addition, MPI derived datatypes have a key role in the MPI-2 I/O operations. In principle, MPI derived datatypes allow a user to more efficiently communicate noncontiguous data (for example, strided data) because the MPI implementation can move the dat...

The MPI Standard does not make any performance guarantees, but users expect (and like) MPI implementations to deliver good performance. A common-sense expectation of performance is that an MPI function should perform no worse than a combination of other MPI functions that can implement the same functionality. In this paper, we formulate some performance requirements and conditions that good MPI...

Standard testing and debugging techniques are notoriously ineffective when applied to parallel programs, due to the numerous sources of nondeterminism arising from parallelism. MPI-Spin, an extension of the model checker Spin for verifying and debugging MPI-based parallel programs, overcomes many of the limitations associated with the standard techniques. By exploring all possible executions of...

A large number of MPI implementations are currently available, each of which emphasize different aspects of high-performance computing or are intended to solve a specific research problem. The result is a myriad of incompatible MPI implementations, all of which require separate installation, and the combination of which present significant logistical challenges for end users. Building upon prio...

background: we sought to assess right ventricular (rv) systolic and diastolic functions via tissue doppler imaging (tdi) in order to discriminate right-to-left (bidirectional) from left-to-right intracardiac shunts. methods: a tissue doppler velocity study via doppler echocardiography was performed in 20 patients with left-to-right shunt (without evidence of significant pulmonary hypertension) ...

BACKGROUND The West-Haven Multidimensional Pain Inventory (MPI) can be used to describe behavioural and psychosocial consequences of long-term pain but little is known about how MPI items and MPI subgroups relate to goals that patients find important in rehabilitation. Life satisfaction measured by the LiSat-11 checklist can be defined as an individual's perception of the difference between his...

Fine-Grain MPI (FG-MPI) supports function-level parallelism while staying within the MPI process model. It provides a runtime that is directly integrated into the MPICH2 middleware and uses lightweight coroutines to implement an MPI-aware scheduler. Our key observation is that having multiple MPI processes per OS-process, with a runtime scheduler can be used to simplify MPI programming and achi...