A SET OF ADA PACKAGES FOR HIGH-PRECISION CALCULATIONS

The packages described here are designed to perform efficient high-acc uracy calculations in cases where there can be serious loss of signifi cance due to rounding errors. Numbers are represented by a value part with a variable number of digits in the mantissa and an error estimate which is updated throughout the calculation and which gives a range o f possible values for the result of the calculation. For economy and s peed, intermediate results are truncated so that the least-significant digits correspond to values only a few orders of magnitude smaller th an the error estimate. Type definitions and the standard arithmetic op erations, together with conversions to and from integers, are provided in one package. The mathematical constants pi and Euler's gamma are i ncorporated to a maximum precision of 320 digits in a package that als o contains all of the standard elementary functions. Separate packages contain input and output procedures and conversion to and from floati ng-point types.