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Multiple precision floating‐point computation in FORTRAN
Author(s) -
Verma S. B.,
Sharan Maithili
Publication year - 1980
Publication title -
software: practice and experience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 70
eISSN - 1097-024X
pISSN - 0038-0644
DOI - 10.1002/spe.4380100302
Subject(s) - fortran , computer science , decimal , calculator , computation , flexibility (engineering) , rounding , floating point , point (geometry) , word (group theory) , arithmetic , algorithm , programming language , mathematics , statistics , geometry , operating system
Abstract By splitting the mantissa of a multiple precision number into BLOCKS of constant width, it has been shown that the precision of a computer can be increased to a degree as high as we please by merely developing a FORTRAN program that can force the computer to perform all arithmetical executions up to any desired number of significant decimal places. Some of the salient features of such a programming are summarized as follows: 1 It reduces inherent errors arising due to approximate nature of representing in some finite number of digits a number that cannot ordinarily be represented exactly in the number of digits available with the particular installation being used. 2 The working of the computer proceeds just as if it were a decimal computer. Naturally we should expect better results even for the same number of digits as the computer normally takes. 3 It takes due care of very low/high numbers occurring in intermediate calculations as one word space is being provided to store the exponent itself. 4 Being problem oriented in nature, the FORTRAN language is most commonly understood by a large section of programmers. It is mainly for this reason that although it requires comparatively more time and space, one can save one's own valuable time in learning complicated assembly languages which differ from computer to computer. 5 It can be easily extended to complex numbers.Here we shall be mainly concerned with the implementation aspect of the program. As regards the variability of the precision, enough flexibility is given to control the precision by changing the size of the number designate arrays.