Release of Open-File Report 95-288, "Direct Solution Package Based on Alternating Diagonal Ordering for the U.S. Geological Survey Modular Finite-Difference Ground-Water Flow Model," by A.W. Harbaugh

To: "File WRD Archive, , Reston, VA "
Subject: OGW Tech MM 95.06 (needs to be put in Mosaic)
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Date: Wed, 10 Apr 1996 13:38:12 -0400
From: "Velvie E Stockdale, Office Automation Assistant, Reston, VA "




In Reply Refer To:                               July 12, 1995
Mail Stop 411


OFFICE OF GROUND WATER TECHNICAL MEMORANDUM NO. 95.06

Subject:  Release of Open-File Report 95-288, "Direct Solution 
          Package Based on Alternating Diagonal Ordering for the 
          U.S. Geological Survey Modular Finite-Difference 
          Ground-Water Flow Model," by A.W. Harbaugh

The subject report describes the addition of a direct solver to 
the MODFLOW ground-water flow model.  For most problems, this new 
solver requires more memory and computer time than the iterative 
solvers; however, it is frequently competitive with iterative 
solvers for small, linear problems.  It may also be useful in 
situations where the iterative solvers have difficulty 
converging.

A version of MODFLOW has been created that incorporates the new 
solver along with most of the other published MODFLOW additions.  
The Hydrologic Analysis Support Section (HASS) is handling 
distribution of this program within the Water Resources Division.  
To obtain the program for use on Data General computers, connect 
to hassrvares.er.usgs.gov/ by anonymous ftp.  Change the current 
directory to pub/GW, and retrieve files modflow.tar.Z and 
readme.modflow.  The readme file contains instructions for 
compiling and installing the program.  Note that unlike the 
previous distribution of MODFLOW, this distribution includes the 
complete source code.  If there are problems retrieving or 
installing the program, contact HASS by electronic mail (wrdapp) 
or by telephone (Steve Regan, 703 648-5896).

Additional copies of OFR 95-288 are available from the Office of 
Ground Water.



                        /s/ William M. Alley
                        Chief, Office
                        of Ground Water

Attachment

Distribution:   A, B, PO, and S (memo only)
                        FO (memo and report)