Scientific Programming - Volume 11, issue 1

Article Type: Other

Citation: Scientific Programming, vol. 11, no. 1, pp. 1-2, 2003

Authors: Hwang, Yuan-Shin | Saltz, Joel

Article Type: Research Article

Abstract: This paper presents a flow-sensitive algorithm to compute interprocedural definition-use chains of dynamic pointer-linked data structures. The goal is to relate the statements that construct links of dynamic pointer-linked data structures (i.e. definitions) to the statements that might traverse the structures through the links (i.e. uses). Specifically, for each statement S that defines links of pointer-linked data structures, the algorithm finds the set of statements that traverse the links which are defined …by S. This algorithm solves the definition-use chaining problem by performing backward iterative data flow analysis to compute the set of upward exposed uses at each statement. The results of this algorithm can be used to identify parallelism in programs even with cyclic pointer-linked data structures. Show more

Keywords: definition-use chains, pointer-linked data structures, data flow analysis, interprocedural analysis, pointer analysis, dependence analysis

Citation: Scientific Programming, vol. 11, no. 1, pp. 3-37, 2003

Authors: Sheshadri, K. | Fritzson, Peter

Article Type: Research Article

Abstract: A symbolic solver generator to deal with a system of partial differential equations (PDEs) in functions of an arbitrary number of variables is presented; it can also handle arbitrary domains (geometries) of the independent variables. Given a system of PDEs, the solver generates a set of explicit finite-difference methods to any specified order, and a Fourier stability criterion for each method. For a method that is stable, an iteration function is generated symbolically using the PDE …and its initial and boundary conditions. This iteration function is dynamically generated for every PDE problem, and its evaluation provides a solution to the PDE problem. A C++/Fortran 90 code for the iteration function is generated using the MathCode system, which results in a performance gain of the order of a thousand over Mathematica, the language that has been used to code the solver generator. Examples of stability criteria are presented that agree with known criteria; examples that demonstrate the generality of the solver and the speed enhancement of the generated C++ and Fortran 90 codes are also presented. Show more

Citation: Scientific Programming, vol. 11, no. 1, pp. 39-55, 2003

Authors: Lu, Quanming | Getov, Vladimir

Article Type: Research Article

Abstract: Java is receiving increasing attention as the most popular platform for distributed computing. However, programmers are still reluctant to embrace Java as a tool for writing scientific and engineering applications due to its still noticeable performance drawbacks compared with other programming languages such as Fortran or C. In this paper, we present a hybrid Java/Fortran implementation of a parallel particle-in-cell (PIC) algorithm for plasma simulations. In our approach, the time-consuming components of this application …are designed and implemented as Fortran subroutines, while less calculation-intensive components usually involved in building the user interface are written in Java. The two types of software modules have been glued together using the Java native interface (JNI). Our mixed-language PIC code was tested and its performance compared with pure Java and Fortran versions of the same algorithm on a Sun E6500 SMP system and a Linux cluster of Pentium~III machines. Show more

Keywords: Java, mixed-language programming, PIC simulation codes, Fortran, high performance computing

Citation: Scientific Programming, vol. 11, no. 1, pp. 57-66, 2003

Authors: Schonfelder, J.L.

Article Type: Research Article

Abstract: This paper describes the design and development of a software package supporting variable precision arithmetic as a semantic extension to the Fortran 95 language. The working precision of the arithmetic supported by this package can be dynamically and arbitrarily varied. The facility exploits the data-abstraction capabilities of Fortran 95 and allows the operations to be used elementally with array operands as well as with scalars. The number system is defined in such a way as to be closed under …all of the basic operations of normal arithmetic; no program-terminating numerical exceptions can occur. Precision loss situations like underflow and overflow are handled by defining special value representations that preserve as much of the numeric information as is practical and the operation semantics are defined so that these exceptional values propagate as appropriate to reflect this loss of information. The number system uses an essentially conventional variable precision floating-point representation. When operations can be performed exactly within the currently-set working precision limit, the excess trailing zero digits are not stored, nor do they take part in future operations. This is both economical in storage and improves efficiency. Show more

Citation: Scientific Programming, vol. 11, no. 1, pp. 67-76, 2003

Article Type: Other

Citation: Scientific Programming, vol. 11, no. 1, pp. 77-78, 2003