Introduction to GAMS IDE
Bruce A. McCarl
&
Dhazn Gillig
Department of Agricultural Economics
Texas A&M University
Download GAMS
You can download the current GAMS distribution by going to
Then
1. Fill out the form
Download GAMS
2. After that user id and the
password will automatically
be e-mailed to you within a
few minutes.
3. Then, follow the instruction
!
Netscape Communicator
Users
!
Internet Explorer Users
!
FTP Users
Download GAMS
Example for FTP Users: Connect to GAMS ftp server ftp.gams.com.
with any ftp client. If you are asked for a password enter: insep34
Download GAMS
Example for FTP Users:
Then download setup.exe or all splitted files in the subdirectory
split if you have a slow or unstable connection. Detailed
Using GAMS IDE to Run GAMS
" Steps to using GAMS IDE
1. Install GAMS and IDE
2. Start the IDE
3. Create and open files
4. House keeping
5. Run GAMS
7. Navigate around outputs
GAMS IDE
- Install from CD
1. Install GAMS and the IDE on your computer
The IDE is automatically installed when GAMS is
installed. To install do the following steps
a. load the GAMS CD into your machine
b. start the installation using the
Windows Explorer and go into the
systems subdirectory called win
then double click on setup.exe
GAMS IDE - Install from GAMS download
1. Install GAMS and the IDE on your computer
The IDE is automatically installed when GAMS is
installed. To install do the following steps
a. go to the directory where you save your setup.exe
b. start the installation by double
click on setup.exe
GAMS IDE – Installation Process
GAMS IDE – Installation Process
c. supply the location for a
license (on your floppy or in
your directory)
GAMS IDE – Installation Process
GAMS IDE
- Create an icon
d. right click on gamside.exe in the GAMS system directory,
choose “create shortcut” and drag the shortcut to your
desktop
GAMS IDE
- Start IDE
2. Start the IDE using it’s icon
a. open your explorer and create a new
sub-directory where you want to save
all your works
b. double click the IDE icon on your desktop
c. create a directory for your work by opening the File
menu and select Project and New project
GAMS IDE
- Start IDE
d. define project name by typing a name for the project in
the “File name” area. All files (programs and output files)
associated with this project will be saved here.
GAMS IDE
- Start IDE
The IDE uses a “Project” file for two purposes.
: to determine where all saved files are placed and where GAMS
looks for files when executing
: to save file names and program options
program
output
log
GAMS IDE
- Cautions on PROJECT
Things always work best when the
project file points to the directory where
the files you want to work on are stored.
This involves contrasting the path of the
project and the files. Here, there is no
problem since the project and the
program file are the same directory.
GAMS IDE
- Cautions on PROJECT
Here, GAMS will look at a file called
tasanadata.dat in
c:\tasana\641class\program\ivan\ and will not
find this file since this file is located in
c:\tasana\641class\program\tasana\.
GAMS IDE
- Open files
3. Open existing files
a. from the model library
Note library is sortable by name, area, type, contributor, and description by
clicking on the heading.
GAMS IDE
b. from your directory
- Open your files
GAMS IDE
- Create a file
4. Create new files
a.
open existing files and with save as dialogue change it’s name
GAMS IDE
- Create a file
b. open the FILE menu and use the NEW option.
You will then get a file called untitled with an empty
screen that you can create (type) your own program.
When finished, save your program using the file SAVE or SAVEAS
dialogue
GAMS IDE
- Improving the display
5. Do a little housekeeping
: The IDE windows are not set up initially as well as they could be.
: To fix this use options dialog under File to alter their characteristics
GAMS IDE
- Improving the display
The Output tab is used to set the output page width and length, date
and time format. Set page length to 99999 or 0 and the page width
range between 72-255.
GAMS IDE
- Improving the display
The Editor tab is used to set font type and size, tabs, and page
margin. Change font size if desired.
GAMS IDE
- Improving the display
The Color tab is used to control color on a program. Alter it if you
wish.
GAMS IDE
- Improving the display
The Execute tab is used to locate the GAMS executable file and set
up the log process window. Check Update Process Window.
GAMS IDE
– Making GAMSIDE Automatically open
The File Extension tab tells the file names that GAMS automatically
is opened for.
To set up first select defaults then add in gck, bas and gdx files.
*.gms program file
*.gpr project file
*.lst
output
*.log log file
GAMS IDE
- Selecting solvers
Solver tab is used to select a solver to solve a problem.
X = current
selection
. = available
selection
- = not available
NLP using MINOS
LP using CPLEX
MCP using PATH
GAMS IDE
License tab
- Alter the license file location
is used to give an alternative license file. Click
locate where the license file is.
to
GAMS IDE
- Run GAMS
6. Run GAMSIDE: clicking the run button or pressing F9
As GAMS is running, the process
window giving a log of steps will appear.
GAMS IDE
- Run GAMS
Note: to get this window, use
Then drag the process window to the far right
GAMS IDE
- GAMS log
6. Run GAMSIDE (con’t)
=>
=>
=>
=>
=>
check if your file is ok
(36) indicate line it is on
execute your file
set up the problem
size of the problem
(23) indicate line SOLVE is on
=> start solver and gives a
name for which solver is
used
=> GAMS restarts
=> GAMS stops without errors
GAMS IDE
- Navigation with IDE
6. Run GAMSIDE (con’t)
!
double click on lines in the process window to access output
!
positioning of your access is determined by the color of the line
•
blue lines => open *.LST file and jump to line in *.LST file
•
black lines => open *.LST file and jump to a location of previous
blue line
•
red lines
=> jump to *.gms file (program) where error occurs
GAMS IDE
- Navigation with IDE
Double clicking on red lines
=> cursor will jump to *.gms file
(program) where error occurs
Note: always concentrate on fixing the first error and ignore the others
since the next errors may be a result of the previous error.
Double clicking on black lines
=> cursor will jump to *.lst file (output)
where error occurs
GAMS IDE
- Equation list
7. Navigate around output
: look for first ---- to find equation listing in *.LST file
: look for the word ‘solution’ or ---- to find solution
Useful Tools –
Open file
Save file
Search text => finds the first occurrence in the current file
Search text => finds the next occurrence in the current file
Search text => finds all occurrences in the directory where
the project is located
Click on a red line to open a file
and on a black line to open a file
and indexes to the particular line
Useful Tools –
parentheses match up
Useful Tools – Column Block
Useful Tools (con’t)
ALT+SHIFT moving column blocks of text
The copy, cut, and paste can be done with the Edit menus as in normal
windows.
GAMS Documentation
"
GAMS documentations are accessible through the HELP menu
GAMS Documentation
GAMS Documentation
"
GAMS documentations are accessible through the HELP menu
GAMS Documentation
"
GAMS documentations are accessible through the HELP menu
Hands On
(handson1.gms, handson2.gms )
Learning Objectives:
1. Acquire basic ability to use IDE
2. Learn how to find and fix errors
3. Learn how to find and interpret GAMS solutions
Suggest things to do
1. Create a project in your directory and called “handson”
2. Do your housekeeping by setting up your options as you like
3. Open and run handson2.gms and navigate through *.LST file
4. Please find and fix those errors
5. Open handson1.gms (your program)
6. Run handson1.gms, then navigate through *.LST file, and find
optimal solutions, shadow prices, and reduced costs along
with their interpretations.
References
McCarl, B. A. Basic GAMS class.
(http://agecon.tamu.edu/faculty/mccarl/mccarl.htm).