Serial machines

The use of concurrence or parallelism in chemistry applications is not new. In the 1980s chemistry applications evolved to take advantage of multiple vector registers on vector supercomputers and attached processors by restructuring the software to utilize matrix—vector and matrix—matrix operations. In fact, once the software had been adapted to vector supercomputers, many applications ran faster on serial machines because of improved use of these machines memory hierarchies. The use of asynchronous disk operations (overlapped computation and disk reads or writes) and a few loosely coupled computers and workstations are other concurrency optimizations that were used before the development of current MPP technology. The challenge of the... 

The optimal choice of preconditioner will ultimately depend on the computer architecture, in as much as some are more readily vectorizable or parallelizable. For example, the initial incomplete Cholesky decomposition methods work well on serial machines, but the forward and backward substitutions are not vectorizable. Simpler decompositions, such as diagonal scaling, run faster on machines like the Cray YMP. More complicated, vectorizable variations of the incomplete Cholesky decompositions have been developed (see, e.g., ref. 24) and are currently under investigation for their applicability to problems in biomolecular electrostatics. Studies of multigridding techniques are also very exciting. 

What has changed with the advent of the parallel computer is the ratio between the performance of a good and bad computer program. This factor is not likely to exceed a factor of two on a serial machine, whereas factors of ten or more are not uncommon on parallel machines."... 

While the D C method makes it possible to carry out semiempirical MO calculations on macromolecules, these computations are still quite expensive. Even with the fastest serial machines available, it is not trivial to do anything beyond single-point calculations on systems that contain several thousand atoms However, when one considers multi-processor machines, the situation is altogether different. The vast majority of the computational work done in a D C calculation is at the subsystem level, with only a limited number of communication operations across the subsystems. This makes the D C algorithm a prime candidate for parallelization. 

The Fourier sum, involving the three dimensional FFT, does not currently run efficiently on more than perhaps eight processors in a network-of-workstations environment. On a more tightly coupled machine such as the Cray T3D/T3E, we obtain reasonable efficiency on 16 processors, as shown in Fig. 5. Our initial production implementation was targeted for a small workstation cluster, so we only parallelized the real-space part, relegating the Fourier component to serial evaluation on the master processor. By Amdahl s principle, the 16% of the work attributable to the serially computed Fourier sum limits our potential speedup on 8 processors to 6.25, a number we are able to approach quite closely. 

Nole In both the above case.s. which are almost similar, so far as the sw itching heats of the stator or the rotor are concertied, the overcurrent protection (noted at serial no. 4) is redundant, as its time constant is much higher (of the order of several minutes) compared to the temperature rise, particularly of the rotor, which is linear and much more rapid under such conditions. Therefore, such protection saves the machine from excessive thermal stresses. 

This kind of simulation requires massive computer power, and much of it is done on so-called supercomputers . This is a reason why much recent research of this kind has been done at Los Alamos. In a survey of research in the American national laboratories, the then director of the Los Alamos laboratory, Siegfried Hecker (1990) explains that the laboratory has worked closely with all supercomputer vendors over the years, typically receiving the serial No. I machine for each successive model . He goes on to exemplify the kinds of problems in materials science that these extremely powerful machines can handle. 

Schnitt, m. cut cutting, incision section intersection slice die edge (of a book) (surgical) operation crop, -band, n. (Micros.) serial section, ribbon, schnlttbearbeltbar, a. machinable. Schnitt-brenner, m. slit burner, batswing burner, -dicke, /, thickness of a slice or section. 

Nameplate data Each machine-train component has a vendor s nameplate permanently attached to its housing. The EIS should include all nameplate data, including the serial number that uniquely identifies a machine or component. 

Knowing the serial number allows detailed information on a machine or component to be obtained. This is possible because machinery manufacturers must maintain records for their products. These records, which are usually identified by serial number, contain complete design and performance data for that specific unit. For example, it is possible to obtain a performance curve or complete bill of materials for each pump found in a plant. 

Margolus (margfiOb] generalizes Feynman s formalism - which applies to strictly serial computation - to describe deterministic parallel quantum computation in one dimension. Each row in Margolus model is a tape of a Turing Machine, and adjacent Turing Machines can communicate when their tapes arc located at the same coordinate. Extension of the formalism to more than one dimension remains an open problem. 

For common preclinical laboratory specimens such as mouse and rat, it is possible to image the skeletal features associated with different developmental stages of serial end-point harvested specimens (Fig. 1). Additionally, with the use of radio-opaque contrast agents, it is possible to image capture the soft tissue features of these specimens (Fig. 2). The combined imaging can be used to illustrate various anatomical features of interest within the same specimen (Fig. 3). This imaging technique therefore has an added potential of conferring multi-modality to an individual micro-CT machine. 

Autoclave. (ABC 009) serial no. (provide number) autoclave is utilized for sterilization of solution buffer vessels, filters, filter housings, closures, filling machine dosing system, and support equipment. The unit has a chamber size of (width x length x height) mm and (provide volume) liter capacity with dual interlocking doors. 

In all communication with us concerning any of our separators please always state the type and serial number of the machine. The type denomination is stamped on the name plate and the serial number on the name plate, the bowl, and the upper rim of the bowl casing in frame. 

The dilution and mechanical agitation can be done by hand or by a machine. Manual preparation cannot be uniform in strength every time a vial is shaken. Machine is needed for the preparation of higher potencies like CM (diluted one hundred thousand times) and MM (diluted one million times). Hahnemann followed the duodecimal system, which was in vogue in his time, in choosing the potency numbers as 6, 12, 24 etc. Higher potencies like 200, 1M, CM, introduced later are based on the metric or decimal system in units. Besides decimal and centesimal series, based on serial dilution of 1 10 and 1 100, respectively, there exists the millesimal series which is based on the serial dilution of 1 1000 and is denoted with the suffix m (Cook, 1988). 

The Sony SDP-1000 [Sony, 1989] was an interesting multiprocessor designed around a serial crossbar interconnect. The controlling machine itself can be divided into three sections ... 

The DSP processing section is shown in figure 5.20. Basically, the 24 serial inputs and 24 serial outputs of the DSPs are connected to a custom crossbar chip. Also included are 8 serial inputs from the outside world and 8 more serial outputs to the outside world which are the final output of the machine. 

The crossbar interconnect is under the control of the microprocessor. The DSPs are programmed remotely, via the microprocessor by the processor s serial port (see section 5.13). The processors all run lock-step and are sample synchronous. Note that only four processors have external memory (and only 64K). This severely limits the reverberation time but in fairness, this machine was not designed for effects processing. Also note that coefficient conversion from real time inputs must take place in the host processor and then be converted into serial form and placed in the specific DSP. 

Just like people, not all machines are created equal. Recognize that identical machine models, including auxiliary equipment, built and delivered with consecutive serial numbers to the same site can perform so differently as to make some products completely unacceptable by the customer even when they were installed properly. 

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