FORTRAN coding

In order to balance public domain science with a high quality commercial software product it has been necessary for us to reimplement almost every aspect of computational chemistry embodied in HyperChem. All HyperChem source code is written in C or C-t-t, specified, designed, and implemented by Hyper-Chem s developers. We have stood on the scientific shoulders of giants, but we have not used their FORTRAN code Thus, although we have had access to MOPAC and other public domain codes for testing and other purposes, HyperChem computes MINDO, MNDO, and AMI wave functions, for example, with HyperChem code, not MOPAC code. We have made the effort to implement modern chemical science in a modern software-engineered product. 

Seeing the success of the UNAMAP BBS, EPA s Office of Air Quality Planning and Standards started a BBS for information on regulatory models in June 1989. This has expanded to a BBS called TTN, Technology Transfer Network. This BBS, in Durham, NC, is reached on (919) 541-5742 and the system operator on (919) 541-5384. A part of this BBS called SCRAM, Support Center for Regulatory Air Models, contains model FORTRAN codes, model executable codes for use on personal computers, meteorological data, and in some cases model user s guides. Much of the information is downloaded in "packed" form, and software to unpack the files must also be downloaded from the bulletin board. 

EQRISK, a FORTRAN code developed by McGuire, 1976. It is available from the National " ormation Service for Earthquake Engineering, University of California, Berkeley. 

A NSS has a computational implementation we have called a GNDL [1,4]. The Fortran code of the algorithm implementing a GNDL can be found described in Program 1 below. The GNDL algorithm constitutes the link between the mathematical notation of the NSS and the computer codification of this operator. 

Bakstad, P., and K. O. Solberg, 1968, RAMONAI A Fortran Code for Transient Analyses of Boiling Water Reactors and Boiling Loops, KR-135, U.K. Atomic Energy Research Establishment, Harwell, England. (3)... 

The latter variable eliminates a finite range [42] of convergence of series both of X at 2 i e, because of a pole due to intemuclear coulombic repulsion as / 0, and of y at V2 Re, for a similar phenomenon as oo. Expressions for Fy in terms of coefficients cj in the latter series are available in a large consistent collection in Fortran coding [43] up to Cio such expressions, readily calculated, through symbolic computation with efficient procedures [44], first in terms of coefficients and thence converted to bj or Cj as required, are further converted to Fortran or C code for numerical applications. 

Application of Helfand s theory has been limited due to the necessity for numerical analysis (although FORTRAN code to facilitate calculations is provided by Helfand and Wasserman (1982) ).This problem was circumvented with the introduction of the seminal analytical SSL theory by Semenov (1985). 

In Figure 6.14 we show a good match between a plot of Equation (6.28) (solid line) and the tabulated values (crosses). Equations (6.27) and (6.28) have then been included in our Fortran code in order to investigate the influence of radiation on the temperature distributions. 

A FORTRAN code has been writen to perform the successive symbolic differenciations of the J functions (12) for any combinntion of atomic states. The / integrals (11) are then evaluated by numerical calculations. This code was inserted in the scattering program developed by the group [7, 8] and tested on the H-H+ benchmark system we obtained results in excellent agreement with those computed in a full Slater Type Orbital treatment, but with a typical factor 10 gain in CPU time. 

And finally, appendices provide a user s guide for the FREZCHEM model and tables of model parameters. Version 9.2 of this model includes the precipitation-dissolution of chloride, nitrate, sulfate, and bicarbonate-carbonate salts of calcium, magnesium, sodium, potassium, and ferrous iron. This version also contains strong acid chemistries (hydrochloric, nitric, and sulfuric), gas hydrate chemistries (carbon dioxide and methane), and tem-perature/pressure dependencies. Electronic copies of the FORTRAN code are available from the senior author (giles.marion dri.edu). 

Program listings and FORTRAN codes for various version of the FREZCHEM model (versions 5.2 to 9.2) are available from the senior author (giles.marion dri.edu http //frezchem.dri.edu). In this appendix, we first describe the data input then we examine four output files that deal with (1) seawater freezing, (2) strong acids, (3) gas hydrates, and (4) a pressure application. But before discussing these examples, there are some limitations that the user needs to be aware of. 

The approximations discussed here are based on FORTRAN code that communicates with the Gaussian 03 [36] suite of programs and the Kohn-ShamDFT program deMon2k [55], These programs have been used for a large number of molecules. The mean absolute deviations presented in the tables illustrate the reliability of these techniques. 

Some chemical process systems may have a single steady state (single solution to a process model) under some design or operation conditions and multiple solutions under other design conditions. There are automatic techniques to vary a parameter of a system model to determine when these solutions branch from a single solution to multiple solutions. The FORTRAN code AUTO is perhaps the most widely used code for this. 

Few new scientific programming projects choose FORTRAN over more transportable and structured C language, but as a result of the millions of lines of existing FORTRAN code, many current projects retain large pieces of FORTRAN. 

Isukapalli S, Roy Z, Georgopoulos PG (2000) Efficient sensitivity/uncertainty analysis using the combined stochastic response surface method (SRSM) and automatic differentiation for FORTRAN code (ADIFOR) Application to environmental and biological systems. Risk Analysis, 20 591-602. 

In addition to handling the conventional vapor/liquid process operations, the ASPEN library of process models includes solids handling and separation units, a set of generalized reactors, improved flash and distillation unit models and process models from the FLOWTRAN simulator. The user can also include his or her own model or key elements of a model, such as the reaction kinetics, in FORTRAN code. 

The ASPEN system is on schedule for a working version to be completed October, 1979. The program system will be comprised of about 150,000 lines of FORTRAN code and data for physical... 

FORTRAN codes of some of the integrals are as large as 300 kilobytes. VEGAS [2] is the only effective method currently available to integrate such huge integrals. 

A subroutine in FORTRAN code is written below for the Thomas algorithm. 

The algorithm is based on the calculation of a row of X in vector sequences. The FORTRAN code in Figure 6 gives a picture of the procedure, but must be coded in CAL, with all vectors labeled Vx being directly replaced by V registers - their dimension is always... 

This integration method can be optimized for the ASC in two steps. The first is to construct the code so that vectorization over each set of equations occurs. Here the main problem is the decision process associated with the application of the "stiff" or "normal" formulas to each equation. If these formulas are implemented in the usual fashion with an IF test in the appropriate DO Loops the smooth flow of contiguous data from core through the CPU will be inhibited and scalar code will result. Optimization of this process can be accomplished by calculating both formulas and applying a multiplicative factor 0 or 1. The following example of Fortran code illustrates this technique. 

FORTRAN code, optimized for the CRAY, which performs the pairwise sum of eq. (1). 

The question of special purpose routines for structural chemistry will be discussed later and attention will now be directed to the construction of the library. It would have been possible to write a small number of strategic routines in Z80A/MVP-9500 assembly language and the remainder of the library in FORTRAN code which made use of the assembler level nucleus. 

Fortran Code for Matrix Multiplication using VPLIB... 

In most intstances however merely being able to arrange the calculation as a series of vector operations, without worrying over the "unit address increment" requirement, makes extremely good if not maximal use of AFPP, VP or AP. As an illustration of this point Table XIII shows "normal" FORTRAN code for a pivotal condensation matrix inverter (the author is unfortunately by now anonymous) and Table XIV shows the vectorized version for the MVP-9500 at about two thirds completion. The VPLIB version is completely (as far as the author can manage at leastl) vectorized and written in assembler. Most of the vectorization is fairly obvious and only the reduction loops contain any obscurity. In order to maintain peak vector efficiency the MVP-9500 reduction loop does a little more work than is strictly necessary an alternative would ruin the vector flow. It is left as an exercise to the determined reader to unravel the full correspondence between Tables XIII and XIV. 

Scalar Fortran Coding of Gauss-Jordan Matrix Inverter... 

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