Scientific Programming - Volume 1, issue 1

Authors: BABB II, ROBERT G. | PERROTT, RON H.

Article Type: Other

Citation: Scientific Programming, vol. 1, no. 1, pp. 1-10, 1992

Authors: BISCHOF, CHRISTIAN | CARLE, ALAN | CORLISS, GEORGE | GRIEWANK, ANDREAS | HOVLAND, PAUL

Article Type: Other

Abstract: The numerical methods employed in the solution of many scientific computing problems require the computation of derivatives of a function f R^N →R^m . Both the accuracy and the computational requirements of the derivative computation are usually of critical importance for the robustness and speed of the numerical solution. Automatic Differentiation of FORtran (ADIFOR) is a source transformation tool that accepts Fortran 77 code for the computation of a function and writes portable …Fortran 77 code for the computation of the derivatives. In contrast to previous approaches, ADIFOR views automatic differentiation as a source transformation problem. ADIFOR employs the data analysis capabilities of the ParaScope Parallel Programming Environment, which enable us to handle arbitrary Fortran 77 codes and to exploit the computational context in the computation of derivatives. Experimental results show that ADIFOR can handle real-life codes and that ADIFOR-generated codes are competitive with divided-difference approximations of derivatives. In addition, studies suggest that the source transformation approach to automatic differentiation may improve the time to compute derivatives by orders of magnitude. Show more

Citation: Scientific Programming, vol. 1, no. 1, pp. 11-29, 1992

Authors: CHAPMAN, BARBARA | MEHROTRA, PIYUSH | ZIMA, HANS

Article Type: Research Article

Abstract: Exploiting the full performance potential of distributed memory machines requires a careful distribution of data across the processors. Vienna Fortran is a language extension of Fortran which provides the user with a wide range of facilities for such mapping of data structures. In contrast to current programming practice, programs in Vienna Fortran are written using global data references. Thus, the user has the advantages of a shared memory programming paradigm while explicitly controlling the data distribution. …In this paper, we present the language features of Vienna Fortran for FORTRAN 77, together with examples illustrating the use of these features. Show more

Citation: Scientific Programming, vol. 1, no. 1, pp. 31-50, 1992

Authors: FOSTER, IAN | OLSON, ROBERT | TUECKE, STEVEN

Article Type: Research Article

Abstract: We describe the PCN programming system, focusing on those features designed to improve the productivity of scientists and engineers using parallel supercomputers. These features include a simple notation for the concise specification of concurrent algorithms, the ability to incorporate existing Fortran and C code into parallel applications, facilities for reusing parallel program components, a portable toolkit that allows applications to be developed on a workstation or small parallel computer and run unchanged on …supercomputers, and integrated debugging and performance analysis tools. We survey representative scientific applications and identify problem classes for which PCN has proved particularly useful. Show more

Citation: Scientific Programming, vol. 1, no. 1, pp. 51-66, 1992

Authors: PICANO, SILVIO | BROOKS III, EUGENE D. | HOAG, JOSEPH E.

Article Type: Research Article

Abstract: We present detailed experimental work involving a commercially available large scale shared memory multiple instruction stream-multiple data stream (MIMD) parallel computer having a software controlled cache coherence mechanism. To make effective use of such an architecture, the programmer is responsible for designing the program's structure to match the underlying multiprocessors capabilities. We describe the techniques used to exploit our multiprocessor (the BBN TC2000) on a network simulation program, showing the resulting performance …gains and the associated programming costs. We show that an efficient implementation relies heavily on the user's ability to explicitly manage the memory system. Show more

Citation: Scientific Programming, vol. 1, no. 1, pp. 67-78, 1992

Authors: BROOKS III, EUGENE D. | GORDA, BRENT C. | WARREN, KAREN H.

Article Type: Research Article

Abstract: We describe a parallel extension of the C programming language designed for multiprocessors that provide a facility for sharing memory between processors. The programming model was initially developed on conventional shared memory machines with small processor counts such as the Sequent Balance and Alliant FX/8, but has more recently been used on a scalable massively parallel machine, the BBN TC2000. The programming model is split-join rather than fork-join. Concurrency is exploited to use a fixed number …of processors more efficiently rather than to exploit more processors as in the fork-join model. Team splitting, a mechanism to split the team of processors executing a code into subteams to handle parallel subtasks, is used to provide an efficient mechanism to exploit nested concurrency. We have found the split-join programming model to have an inherent implementation advantage, compared to the fork-join model, when the number of processors in a machine becomes large. Show more

Citation: Scientific Programming, vol. 1, no. 1, pp. 79-89, 1992

Authors: METCALF, MICHAEL

Article Type: Research Article

Abstract: A few weeks before the formal publication of the ISO Fortran 90 Standard, NAG announced the world's first f90 compiler. We have evaluated the compiler by using it to assess the impact of Fortran 90 on the CERN Program Library.

Citation: Scientific Programming, vol. 1, no. 1, pp. 91-95, 1992