General GAMSCHK Information – Bruce McCarl
Source: https://agecoresearch.tamu.edu/mccarl/gams-related-information/general-gamschk-information/ Parent: https://agecoresearch.tamu.edu/mccarl/
What are the basic functions of GAMSCHK?\ \ How is GAMSCHK used in a GAMS program?\ \ How do I obtain GAMSCHK?\ \ How can I get a copy of the latest writeup?\
What are the basic functions of GAMSCHK?
- Display the structure of user selected equations and/or variables
- List the characteristics of selected groups of variables and equations
- List the characteristics of equation and variable blocks
- Examine a GAMS model to see whether any variables and equations contain specification errors
- Generate a schematic of the structure of the variable and equation blocks
- Examine the number of coeficients in the intersections of variable and equation blocks
- Look at the scaling characteristics of the variable and equation blocks
- Form a schematic for model components depicting the location of coefficients by sign and magnitude
- Reconstruct the reduced cost of variables after a model solution
- Reconstruct the activity within equations after a model solution
- Find variables or equations which could be causing unbounded or infeasible models
\ Top of Document\ \ How is GAMSCHK used in a GAMS program? \ There are two elements to the use of GAMSCHK
- Modification of the GAMS program
- In the GAMS program you must make GAMSCHK the chosen solver by entering a line like\ option lp=gamschk;\ The rest of the program is like any other GAMS model
- Creation of the gck file
- In addition GAMSCHK requires that the user indicate which procedures are to be employed. This is specified through the use of the *.GCK file where the * refers to the filename from the GAMS execution instruction. Thus if you are solving a model called trnsport you use a file called trnsport.gck.
Top of Document\ \ \ How do I obtain GAMSCHK?
GAMSCHK is a standard part of all GAMS releases.\ If you do not have a copy you need to update your system.\ \ Top of Document\ \ How can I get a copy of the latest writeup?
GAMSCHK is a standard part of all GAMS releases. The GAMSCHK manual is included in the Solver Manual Book\ Also a current version can be gotten from GAMSCHK Documentation\ \ Top of Document