High Performance Fortran Forum. High Performance Fortran Specification. January 1993.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....constructs and semantics of our new language, and give a simple example that contrasts ZPL with other data parallel languages. 1 Introduction A variety of languages have been proposed that generally provide data parallel or array semantics, including C [15] Fortran 90 [1] NESL [4] and HPF [8]. One characteristic of these languages is that data parallelism is the only model provided. This fact introduces a certain pressure to support a wide range of general purpose facilities. Though this has resulted in rich and interesting languages, it has not always served the goals of simplicity, ....

High Performance Fortran Forum. High Performance Fortran Specification. January 1993.

....Since this difference is irreconcilable, except for data parallel languages, we restrict our attention to MIMD parallel machines. We believe that portability across SIMD and MIMD machines can be accomplished by implementing a common data parallel language such as High Performance Fortran [1, 2, 3] on SIMD machines using native machine primitives and on MIMD machines using a system such as Charm. 1 1.1 Requirements of a parallel programming system A general technique for dealing with complexity involves employing a hierarchical structure. In order to identify the appropriate hierarchy to ....

....programming task. If the mechanisms are well matched for the application at hand, and if the programmer is experienced in using them, they work very well. 3. In both of the above approaches, the programmer specifies the decomposition, the mapping, and scheduling. The High Performance Fortran [1, 2] standard is an example of approaches which free the programmer from the task of scheduling. The programmer still specifies the decomposition (via array distribution primitives) and mapping (implicitly, via the owner computes rule, which specifies that a computation is carried out on the ....

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High performance FORTRAN forum. High Performance FORTRAN specification. Technical report, Rice University, Houston, TX.

....work attempts to extend these approaches to work for library level optimizations. Our work is not the first to use annotations to convey information to compilers. For example, DyC [21] uses annotations to guide dynamic compilation, and other annotations, such as HPF s data distribution directives [24], are complex enough that they effectively redefine the language. Still other compilers use hints or pragmas to guide optimizations such as inlining and loop unrolling, and to indicate that certain procedures are pure functions. To our knowledge, none of these hints or pragmas allows information ....

High Performance Fortran Forum. High Performance Fortran Specification. November 1994.

....languages [4, 5, 15] give the programmer no control over data decomposition, leaving these issues to the compiler or hardware. But because the best choice of data decomposition depends on characteristics of the application, compilers can make poor data placement decisions. Many recent languages [6, 22] provide support for data decompositions, but hide communication operations from the programmer and thus do not encourage locality at the algorithmic level. Consequently, there is a reliance on automated means of hiding latency. Unfortunately, these techniques multithreaded hardware, multiple ....

....unified in the ensemble structure, all three components can be reconfigured and scaled in a coherent, concise fashion to provide flexibility and portability. The data partitioning aspect of ensembles is analogous to the data partitioning features supplied in languages such as HPF [22], but since ensembles also incorporate communication and code components, ensembles provide greater control over performance. For instance, the code ensemble may logically have identical procedures in each section, but they may be different, effectively yielding MIMD execution with the ....

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High Performance Fortran Forum. High Performance Fortran Specification. January 1993.

....programmer no control over data decomposition, leaving these issues to the compiler or hardware. But because good data decompositions can depend on characteristics of the application that are difficult to determine statically, compilers can make poor data placement decisions. Many recent languages [6, 22] provide support for data decompositions, but hide communication operations from the programmer and thus do not encourage locality at the algorithmic level. Consequently, there is a reliance on automated means of hiding latency multithreaded hardware, multiple lightweight threads, caches, and ....

....processor is not visible to the programmer, but the programmer can change the partitioning clauses on the data aggregates. SPMD processing is allowed, but there are no special facilities for handling edge effects. Fortran Dialects. Recent languages such as Kali [26] Vienna Fortran [6] and HPF [22] focus on data decomposition as the expression of parallelism. Their data decompositions are similar to the Phase Abstractions notion of data ensembles, but the overall approach is fundamentally different. Phase Abstractions require more effort from the programmer, while this other approach relies ....

High Performance Fortran Forum. High Performance Fortran Specification. November 1994.

....of Parallel Programming Our analysis and transformations are appropriate for shared memory paradigms where accesses to shared data can be parameterized by variables that have different values for different processes. Examples of these variables include induction variables of FORALL loops in HPF [Hig93] and private variables, such as pid in Figure 1, in the fork join model. Our current implementation targets programs that use the latter: coarse grained, explicitly parallel C programs that execute on shared memory multiprocessors. Examples of such programs can be found in the Stanford SPLASH ....

High Performance Fortran Forum. High Performance Fortran Specification. January 1993.

....to show it equivalent to the original Fortran. Tools can assist in this validation [1] and the additional effort is generally repaid in better performance and a cleaner, more easily maintained program. 2 A Brief Introduction to HPF HPF was designed by the High Performance Fortran Forum in 1993 [4]. HPF extends sequential Fortran by adding data decomposition directives that do not change the semantics of the program, but serve as hints to the compiler to improve performance. Thus HPF provides data parallelism by adding data decomposition information to sequential programs. HPF programmers ....

High Performance Fortran Forum. High Performance Fortran Specification. November 1994.

....environment consists in formal tools, whose goal is to help the programmer to have a better understanding of the programming model. For instance, a proof system may offer a privileged simple vision, by using some properties like determinism or compositionality. Although data parallel languages [9], 20] 5] 28] 10] only enable to express a particular subset of problems, they can exploit inherent parallelism by applying the same operation to a set of data distributed on the target computer. In opposition to control parallel languages, where the programmer has to manage multiple ....

....concepts. Following [11] we can remark that data parallel languages come either from SIMD extensions of sequential languages, or from more abstract parallel concepts such as collection oriented languages. From the first category, we can highlight languages like CM Lisp [28] C [5] or HPF [9], which at first often had only regular communication dependent on the machine network topology. Languages coming from the second category are for example 8 1 2 [21] CAML Flight [4] DPML [10] and mostly have an asynchronous execution model which allows execution on any architecture. DP log ....

High Performance Fortran forum. High Performance Fortran specification. CITI/CRPC, Rice University, Houston, January 1993. Version 1.0 Draft.

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