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Models of Data Structures in the Main MemoryComputerized data processing based on DL coding may be realized by the method of processing with a fixed number Fig.3.1. Illustration of a calculation process with a fixed value In this algorithm of processing, the operands in each arithmetic operation are limited by the value When defining - a very large - in the case of a small A situation may occur when It follows from the mentioned above, that the problem of obtaining an acceptable accuracy of calculation using the method of processing based on DL arithmetic with a fixed It is important to develop a model of calculation which would allow finding an optimal number of significant digits in DL structures for problem solving with a necessary accuracy. Another variant of computerized data processing based on using DL structures is the method of processing with an adaptive value of the number Q of significant digits in DL data [1-2]. In this method of processing, there are no limitations on Q. In data processing that value of Qad is used this is equal to the maximal value of Q among all the DL structures at the beginning of solving a given problem. The given value does not limit the bit length of the result and is used as an initial in the method of accuracy-based adaptation. The process of calculation and the involved DL data with an adaptive value Qad of the number of significant digits, are shown schematically in Fig. 3.2. Fig.3.2. Illustration of a calculation process with an adapted value Qad. Fig.3.2 shows that Qad may vary during data processing. This method of processing, as well as previous variant, enhances the capabilities of a computer as far as the accuracy indices are concerned. Besides, both mantissa normalization procedure and results rounding procedure are eliminated here. The range of DL data is limited not by the method of processing, but only by the length of binary words which represent the values of DL code digits in the computer environment during data storage, transportation, and processing. The length of the working field of DL data is adjusted, in an adaptive manner, to the precision of the computational problem being solved. If the number of bits in the result À of a certain computing operation exceeds Qad (the value of The range of DL data is also adaptive by precision as the variation boundaries of the values The adaptive method of processing is limited by the used memory and time recourse. The greater the value Qad becomes, the larger volume of memory is necessary to represent DL data, and more time will be used for processing. So, this variant of computer processing based on DL data representation also does not give an unambiguous solution of the problem of assuring an acceptable accuracy. A computational model should be developed that would save time and memory spent on data processing with the minimal loss in the accuracy of the results of DL operations.
Date: 2015-12-24; view: 886
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