Premium
Techniques for the compression of sequences of integer numbers and real numbers with fixed absolute precision
Author(s) -
Stradella Omar G.,
Corongiu Giorgina,
Clementi Enrico
Publication year - 1993
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.540140607
Subject(s) - fortran , unpacking , subroutine , integer (computer science) , basis (linear algebra) , computer science , space (punctuation) , mathematics , algorithm , arithmetic , geometry , programming language , philosophy , linguistics , operating system
Algorithms to reduce the space needed to store information either in memory or magnetic media are presented. These algorithms were designed to pack and unpack two common kinds of data types: sequences of sets of integers that change in a regular fashion and real numbers of fixed absolute precision. One typical application of these techniques is in the storage of electron repulsion integrals in ab initio calculations, where the indices of the basis functions are a good example of data of the first type and the integrals of the second type. In this case, savings in storage space of 50% or more can be obtained with reasonable accuracies in the energies. FORTRAN subroutines are presented for packing/unpacking indices and integrals both in the IBM and IEEE 754 64‐bit floating point formats. © 1993 John Wiley & Sons, Inc.