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523. AMPAC:Version for IBM Mainframe Computers
(Version 1.0)
Modified by Lee L. Lynn, Thomas H. Pierce and Charles H. Reynolds, Computer Applications Research, Rohm and Haas Company, Spring House, Pennsylvania 19477, after the Dewar Research Group, Department of Chemistry, The University of Texas, Austin, Texas 78712 and J.J.P. Stewart, Seiler Research Labs, U.S. Air Force Academy, Colorado Springs, Colorado 80840 AMPAC (QCPE 506) is a general-purpose semiempirical quantum package which encompasses the MINDO/31, MNDO2 and AM13 Hamiltonians. We have converted this program directly to run on IBM mainframe computers under either the MVS or VM operating system. In addition to the source code, sample JCL is provided for compiling, linking and running AMPAC under MVS. Since AMPAC uses numerous variables before they are explicitly assigned a value, they must all be zero at the beginning of the calculation. Under VM, this can be accomplished by simply loading the program with the "/CLEAR" option. Unfortunately, there is no such option under MVS, but it is possible to clear the memory by using the linkage editor parameter "SCTR". An example of the use of the "SCTR" parameter is included in the sample JCL for compiling AMPAC under MVS. There are two changes which will be necessary to use this version of AMPAC at most sites: 1. Subroutine SECOND has been modified to return the correct CPU time at our installation. This code will most likely not work at other installations and will need to be modified accordingly. 2. We have added a checkpoint restart routine so calculations can be preserved during system outages. This is also a site-specific routine and may be replaced or simply removed. (We have COMMENTED out the two lines in ITER which invoke check-point restart). There are two additional subroutines in this version of AMPAC which do not appear in the original program. The first, subroutine INTGEO, periodically dumps the updated geometry to a file during calculations when a normal geometry optimization is being performed. The second, subroutine THPOUT, writes a file which is compatiblewith ourin-housemolecular graphics/modeling system, MOLY4. This routine has been left in because we anticipate releasing a version of MOLY for general use in the near future. If either of these capabilities are unwanted, they can easily be removed by deleting the CALL statements in subroutines FLEPO and WRITE. We have implemented this program on IBM 4381, 3084 and 3090 computers and have no reason to believe it would not run on any other IBM mainframes under either MVS or VM. __________ References: 1. R. C. Bingham, M.J.S. Dewar, D. H. Lo, J. Am. Chem. Soc., 97, 1285, 1294, 1302, 1307 (1975). 2. M.J.S. Dewar and W. Thiel, J. Am. Chem. Soc., 99, 4899, 4907 (1977). 3. M.J.S. Dewar, E. G. Zoebisch, E. F. Healy, J.J.P. Stewart, J. Am. Chem. Soc., 107, 3902 (1985). 4. T. M. Dyott, A. J. Stuper, G. S. Zander, J. Chem. Inf. Comput. Sci., 20, 28 (1980). __________ FORTRAN (IBM VMS) Lines of Code: 16,000 NOTE:This system is delivered as 10 separate files on its own magnetic tape. |