International Ground Water Modeling Center (IGWMC)             SIM_ADJUST(1)

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NAME
     SIM_ADJUST -- A Computer Code that Adjusts Simulated Equivalents for 
                   Observations

ABSTRACT
     
     This report documents the Sim_Adjust computer code. Sim_Adjust surmounts 
     an obstacle that is sometimes encountered when using universal analysis 
     computer code such as UCODE_2005 (Poeter and others, 2005), PEST (Doherty, 
     2004), and OSTRICH (Matott, 2005; Fredrick,et al., 2006). These codes read 
     simulated equivalents from a list in a file produced by a process model 
     such as MODFLOW that represents a system of interest. At times values 
     needed by the universal code are missing or assigned default values 
     because the process model could not produce a useful solution. Sim_Adjust 
     can be used to (1) read a file produced by a process model that contains 
     simulated equivalents to observations in space or tab delimited columns of 
     data that include a column of simulated values and a column of related 
     observation names; (2) identify observations that have been omitted or 
     assigned a default value by the process model, and (3) define alternate 
     simulated values or defaults. The user may provide a constant replacement 
     value, or may indicate that an alternative simulated value from the 
     process model should be used. The user may also provide a sequence of 
     alternatives. Indeed, a long chain of alternative values can be specified. 
     For example, the heads from a series of cells may be specified to provide 
     a simulated value for comparison with an observation in a cell that may 
     become dry.
     
     Sim_Adjust reads an input file specifying the file name containing the 
     simulated equivalents, its layout, and default values, followed by 
     instructions defining the substitution procedure in the event that a 
     simulated equivalent is missing or assigned a default by the process model.  
     It then determines which simulated equivalents are missing or assigned a 
     default in a file produced by a process model, and creates a similar file 
     containing all simulated equivalents with their appropriate alternative 
     values.
     
     Sim_Adjust is constructed using modules from the JUPITER API, and is 
     intended for use on any computer operating system. Sim_Adjust consists 
     of algorithms programmed in Fortran90, which efficiently performs 
     numerical calculations.


HISTORY

     SIM_ADJUST Version 1.000 3/27/2008 - Initial release.


DATA REQUIREMENTS
     In order to use SIM_ADJUST, the process model needs to be constructed and
     the main SIM_ADJUST input file needs to be created. Input data are read
     from files.


SYSTEM REQUIREMENTS
     SIM_ADJUST is written primarily in Fortran 90. The code has been used on
     UNIX-based computers and personal computers running various forms of the
     Microsoft Windows operating system.


CONTACTS

    Eileen Poeter
    International Ground Water Modeling Center and the Colorado School of Mines
    Golden, Colorado 80401
    USA

    epoeter@mines.edu

    Mary C. Hill
    U.S. Geological Survey
    National Research Program
    3215 Marine St
    Boulder, CO 80302
    USA

    mchill@usgs.gov