Floating point data

Notice how the lab value variable has been rounded to an arbitrary precision to the ninth decimal place. This gets around the floating-point comparison problem, while at the same time it avoids rounding the lab value variable to a precision where meaningful data are lost. 

Data management in RS/1 is based on two-dimensional tables. Each cell of a table can contain data representing fixed or floating point numbers, dates, times, or free text. Cells in a particular column are not all constrained to the same type it is possible, for example, to include a note about some missing data in a column of numerical results. A user can work with many hundreds of tables. Tables are based on disk files, accessed through a kind of paging scheme, so there is no limit on table size. Some users work with tables containing hundreds of columns and tens of thousands of rows. 

Data transfers, in floating point engineering units or in status states, are requested by the expert system. Thus the distributed system does not transmit all measurements and alarms on a fixed scan basis, but rather the process data are accessed as required for inference. In a sense, the expert system is acting like an expert operator, who focuses attention or scans the process operation selectively, using expertise to determine specific areas of attention. 

The Zoran 38000 has an internal data path of 20 bits as well as a 20 bit address bus. The two accumulators have 48 bits. It can perform a Dolby AC-3 [Vernon, 1995] five channel decoder in real time, although the memory space is also limited to one Megaword. It has a small (16 instruction) loop buffer as well as a single instruction repeat. The instruction set has support for block floating point as well as providing simultaneous add and subtract for FFT butterfly computation. 

The best-known uses of computers in chemistry rely on floating point computation. Numerical quantum chemistry, chemometrics and the collection and evaluation of experimental data, e.g. in X-ray crystallography, modern spectroscopy (advanced NMR, MS, IR) and chemical dynamics are major areas where floating point computation is indispensable. 

Both types of calculations can require very large data arrays - to more than 10 floating point numbers, and future arrays may be even 1 to 2 order of magnitude larger. 

As we have seen on the CRAY the ability to gather data together is essential. Memory speed must be commensurate with floating point speed. When nearest neighbor tables are used fast scatter operations are also needed. The two essential random memory operations needed are ... 

The second possibility for improving microcomputer floating point performance lies with the North Star Hardware Floating Point Board (3). This device executes floating point, add, subtract, multiply and divide with up to twelve decimal digits of precision. One byte of data is reserved for the exponent and the other six for the mantissa of each floating point number. 

The problem of floating point format differences was the most pressing one and was solved in the following way. All data arrays to be operated upon by the MVP-9500 are converted to the... 

It has been the author s experience that most chemical computations, structural or otherwise, which involve a significant amount of floating point arithmetic are reducible to vector format. The exercise is usually worthwhile as in most cases the chemist is using the same program over and over again with different data sets. 

FDDI Fiber distributed data interface an optical fiber based interconnect. FLOPS Floating point operations per second. 

You can enter numbers in E format but they will automatically be converted to floating point. You can t enter numbers as percentages the percent symbol has another meaning in VBA (see "VBA Data Formats" later in this chapter). 

The Variant data type is the default data type in VBA. Like Excel itself, the Variant data type handles and interconverts between many different kinds of data integer, floating point, string, etc. The Variant data type automatically chooses the most compact representation. But if your procedure deals with only one kind of data, it will be more efficient and usually faster to declare the variables as, for example. Integer. 

You can also specify the data type of the return value. If none is specified, the Variant data type will be returned. In the example of the preceding section, MolWt returns a floating-point result. The Variant data type is satisfactory ... 

Pentium The Pentium represents the evolution of the 80486 family of microprocessors and adds several notable features, including 8K instruction code and data caches, built-in floating-point processor and memory management unit, as well as a superscalar design and dual pipelining that allow the Pentium to execute more than one instruction per clock cycle. 

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