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Integer Representation of Decimal Numbers for Exact Computations



Javier Bernal, Christoph J. Witzgall


A scheme is presented and software is documented for representing as integers input decimal numbers that have been stored in a computer as double precision floating point numbers and for carrying out multiplications, additions and subtractions based on these numbers in an exact manner. The input decimal numbers must not have more than nine digits to the left of the decimal point. The decimal fractions of their floating point representations are all first rounded off at a prespecified location, a location no more than nine digits away from the decimal point. The number of digits to the left of the decimal point for each input number besides not being allowed to exceed nine must then be such that the total number of digits from the leftmost digit of the number to the location where round-off is to occur does not exceed fourteen.
Journal of Research (NIST JRES) - Research
Report Number


computational geometry, Delaunay triangulation, exact integer arithmetic, power diagram, regular triangulation, robustness, Veronoi diagram


Bernal, J. and Witzgall, C. (2006), Integer Representation of Decimal Numbers for Exact Computations, Journal of Research (NIST JRES), National Institute of Standards and Technology, Gaithersburg, MD, [online], (Accessed February 22, 2024)
Created March 30, 2006, Updated March 1, 2021