REPORT--Evaluation of the efficiency of several matrix solving programs.


               UNITED STATES DEPARTMENT OF THE INTERIOR
                           GEOLOGICAL SURVEY
                        RESTON, VIRGINIA  22092

                                                August 25, 1976

GROUND WATER BRANCH TECHNICAL MEMORANDUM NO. 76.13-T

Subject:  REPORT--Evaluation of the efficiency of several matrix
                  solving programs.

Enclosed for your information is a technical memorandum by Messrs.
Richard Wells, James Mercer, and Charles Faust, of the
Northeastern Region, giving the results of an evaluation and
comparison of execution time for several computer programs used to
solve systems of linear equations having a banded nonsymmetric
coefficient matrix.  Such systems of equations arise in numerical
models for transport processes in ground-water systems, a subject
of growing interest and importance in WRD districts.

Although the work was concerned primarily with modeling
applications to ground-water problems, we expect that these
results will be of interest to modelers in other disciplines.
Listings of the solution techniques are included in the
memorandum.

On the basis of evaluation, the authors make recommendations
regarding which programs, among those considered that require the
least amount of execution times, depending on the nature of the
problem.  We would appreciate being advised of any comparable
types of evaluations by district personnel of the performance--in
terms of run time and/or accuracy--of other computer programs that
solve banded nonsymmetric matrices.



                              (s) C. A. Appel
                              For, Chief, Ground Water Branch
                              Water Resources Division

Enclosure

WRD Distribution:  A, B, S, FOL