A Program Visualization System That Supports the Program Understanding Process.

The goal of this research is to provide a graphical system that supports the program understanding process by representing the program\u27s control flow, the code and the identifiers local to a specific point within the program. By having more information local to the point of interest, the programmer can maintain continuity in developing program understanding. The programmer can see loops, procedure calls, and other structures with respect to their execution order and can view them in the environment or the context in which they will execute. The Peec system supplies a graphical representation of the program\u27s control flow in which the control structures are represented as tiers. The tiers are arranged in a three-dimensional space representing the program\u27s operational flow. The body of the procedure or function is nested within the reference tier so that the programmer views the routine local to its reference point. Also, a list of live identifiers is displayable for the current tier element. The advantage is that the routine\u27s text and the identifier list are local to the area of study and the programmer does not have to look elsewhere for the program text and the identifier definition. The programmer can maintain a continuity in developing program understanding using information local to the point of interest. The Peec system consists of the Peec compiler which transforms a Pascal program into tier and identifier information, and the Peec environment for modeling the program\u27s operational flow image. The Peec environment provides the programmer many interactive capabilities. These capabilities consist of browsing the flow model, displaying text, displaying identifiers and transforming the three-dimensional flow model into appropriate views. These features are aimed at assisting the programmer in the processing of developing program understanding

Reachability and Termination Analysis of Concurrent Quantum Programs

We introduce a Markov chain model of concurrent quantum programs. This model is a quantum generalization of Hart, Sharir and Pnueli's probabilistic concurrent programs. Some characterizations of the reachable space, uniformly repeatedly reachable space and termination of a concurrent quantum program are derived by the analysis of their mathematical structures. Based on these characterizations, algorithms for computing the reachable space and uniformly repeatedly reachable space and for deciding the termination are given.Comment: Accepted by Concur'12. Comments are welcom

SoC Software Components Diagnosis Technology

A novel approach to evaluation of hardware and software testability, represented in the form of register transfer graph, is proposed. Instances of making of software graph models for their subsequent testing and diagnosis are shown.Comment: 4 page

CLPGUI: a generic graphical user interface for constraint logic programming over finite domains

CLPGUI is a graphical user interface for visualizing and interacting with constraint logic programs over finite domains. In CLPGUI, the user can control the execution of a CLP program through several views of constraints, of finite domain variables and of the search tree. CLPGUI is intended to be used both for teaching purposes, and for debugging and improving complex programs of realworld scale. It is based on a client-server architecture for connecting the CLP process to a Java-based GUI process. Communication by message passing provides an open architecture which facilitates the reuse of graphical components and the porting to different constraint programming systems. Arbitrary constraints and goals can be posted incrementally from the GUI. We propose several dynamic 2D and 3D visualizations of the search tree and of the evolution of finite domain variables. We argue that the 3D representation of search trees proposed in this paper provides the most appropriate visualization of large search trees. We describe the current implementation of the annotations and of the interactive execution model in GNU-Prolog, and report some evaluation results.Comment: 16 pages; Alexandre Tessier, editor; WLPE 2002, http://xxx.lanl.gov/abs/cs.SE/020705

SKIRT: hybrid parallelization of radiative transfer simulations

We describe the design, implementation and performance of the new hybrid parallelization scheme in our Monte Carlo radiative transfer code SKIRT, which has been used extensively for modeling the continuum radiation of dusty astrophysical systems including late-type galaxies and dusty tori. The hybrid scheme combines distributed memory parallelization, using the standard Message Passing Interface (MPI) to communicate between processes, and shared memory parallelization, providing multiple execution threads within each process to avoid duplication of data structures. The synchronization between multiple threads is accomplished through atomic operations without high-level locking (also called lock-free programming). This improves the scaling behavior of the code and substantially simplifies the implementation of the hybrid scheme. The result is an extremely flexible solution that adjusts to the number of available nodes, processors and memory, and consequently performs well on a wide variety of computing architectures.Comment: 21 pages, 20 figure