Programming Models and Tools

For efficient execution, a parallel algorithm must possess the following attributes, which must be expressed in the programming language  

Tolerance of latency and low bandwidth for references to remote memory locations 

A scalable algorithm is one that will execute with acceptable efficiency on large numbers of processors. One way to assess this attribute is through construction of a model for the execution of the code that combines costs from all parts of the algorithm. The result is a function such as 

Here the execution time (T) of the program is described as a function of the number of processors ( ), the problem size (N), the memory size (M), the latency and transmission time of remote memory references (fO,tl), and other relevant parameters. We understand already that T can be a nonlinear function of the problem size and sensitive to the algorithm [e.g., conventional self-consistent field (SCF),29 T(N) = 0 N ) + 0 N ) vs. pseudospectral SCF, T(N) = 0 N ) + 0(N3)], and similarly the dependence on P can be complex. As discussed earlier, one measure of the efficiency of parallel execution may then be derived as follows  

Kumar and Singh suggested that a more useful function for analysis of seal-ability is the isoefficiency function 

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The choice of memory access methods, which is determined by the programming model and tools, is subject to great variation. This topic is discussed in a later section that deals with models and tools. Typical memory access... 

Many other models and tools were presented as well for maintenance HF treatment. Examples include INDICATE, a program launched by the AustraUan Transport Safety Bureau (ATSB 1999) in the late 1990 s. which was preceded by a number of proactive tools (Reason 1996) which were intended to monitor organizational latent conditions that may give rise to safety failures. Also developed were the... 

Process owners require more comprehensive levels of training to fully understand their role and responsibilities within the program. Process owner training should teach key concepts and tools that owners will need to evaluate and support their processes. This training can be done in a phased approach to support the elevation and advancement of a process within the organization s chosen maturity model. 

Since its introduction in 1971, SPICE (Simulation Program with Integrated Circuit Emphasis) has become the most popular analog simulation tool in use today. In the last 15 years, we have seen explosive growth in the use of SPICE, with the addition of Berkeley SPICE 3 enhancements, and support for C code model and mixed-mode simulation using XSPICE (Cox et al. 1992, Kielkowski 1994).We have also seen many new companies emerge as developers of SPICE-based simulation tools, most of which are currently available for the PC platform. 

In 1983, SPICE 2G.6 was released and remained the industry standard for many years. Motivated by the increased use of UNIX workstations and superior programming tools, SPICE 2 was converted into the C programming language and released as SPICE 3. Although SPICE 3 is not entirely backward compatible with SPICE 2, the new features far outweigh this drawback. SPICE 3 has a technical advantage of being readily modified because it is written in C. SPICE 3 also offers more and improved device models and analysis functions. 

As a result of the observed limitations inherent in all indices (but the nevertheless high value placed on them as predictive tools), researchers have continued over the years to devise various charts, models, and computer programs as aids or replacements for them. These include the Kunz Model, Burroughs NTU Model, Captain BAISPEC Program, and Cooling Tower Carbonate Equilibrium (CTCE) Model. 

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