Abstract: A method for executing calculation of the Hartree-Fock method in a molecular orbital method by a distributed memory parallel computing system includes the steps of: using a computer cluster made up of a plurality of computers; dividing a density matrix into multiple density submatrixes and distributing them to the individual computers and storing therein; and executing calculation processes such as two-electron integration or the like relating to density submatrixes in each computer while sequentially transferring the multiple density submatrixes between the multiple computers.

Abstract: A parallel computing method by using a parallel computer having a plurality of processors is provided, wherein when a 2-electron integration is transformed from an atomic-orbital base (rs|tu) to a molecular-orbital base (ab|cd), indexes r and s of an atomic orbital to be calculated are designated for the plurality of processors and each of the plurality of processors performs processing for all combinations of designated indexes R and S, and indexes t and u of the atomic orbital to be calculated. Subsequently, the grain sizes are equalized, many commodity processors can be connected with high performance, and the cost of a high-speed operation computer reduces. Further, the computer can obtain a large main-memory area, as a whole, through the use of inexpensive local memories.

Abstract: A molecular simulation method for dividing a molecule or a part of molecule to be simulated into a QM space and an MM apace and applying an ab initio molecular orbital method to the QM space and a method based on an empirical potential to the MM space to perform molecular simulation includes the steps of: retrieving structure data on the molecule or part of molecule to be simulated from a storage unit, and dividing the structure data into the QM space and the MM space; and replacing a part of a total energy expression in the ab initio molecular orbital method concerning the QM space with an empirical potential.

Abstract: A method for executing calculation of the Hartree-Fock method in a molecular orbital method by a distributed memory parallel computing system includes the steps of: using a computer cluster made up of a plurality of computers; dividing a density matrix into multiple density submatrixes and distributing them to the individual computers and storing therein; and executing calculation processes such as twoelectron integration or the like relating to density submatrixes in each computer while sequentially transferring the multiple density submatrixes between the multiple computers.

Abstract: A parallel computing method by using a parallel computer having a plurality of processors is provided, wherein when a 2-electron integration is transformed from an atomic-orbital base (rs|tu) to a molecular-orbital base (ab|cd), indexes r and s of an atomic orbital to be calculated are designated for the plurality of processors and each of the plurality of processors performs processing for all combinations of designated indexes R and S, and indexes t and u of the atomic orbital to be calculated. Subsequently, the grain sizes are equalized, many commodity processors can be connected with high performance, and the cost of a high-speed operation computer reduces. Further, the computer can obtain a large main-memory area, as a whole, through the use of inexpensive local memories.