Run ampl with python script

[Alberto Reuters]

Hello,

Nowadays I'm executing ampl manually and then in its environment I
type include myfile.run;. I need run my model through python script.
Does anybody know how can I send the command "include" into ampl,
after start it with python?

Thank you.

[Paul]

What about having the Python script write a temporary file that looks like

model mymodel.mod;
data mydata.dat;
include myotherfile.txt;
solve;

or something along those lines, then call AMPL with that temporary file as argument?  Or pipe the equivalent to AMPL through stdin?

Paul

[Robert Fourer]

The command "ampl myfile.run" initiates AMPL, includes the file myfile.run,
and then terminates after all commands in myfile.run have been executed. So
one way to run your model from Python is to use Python's os module or
subprocess module to execute "ampl myfile.run". To get results back from
AMPL you will need to place some commands in myfile.run that write one or
more files for your Python script to read.

If you have several AMPL input files as Paul suggests, you can get AMPL to
read them one at a time by running a command like "ampl mymodel.mod
mydata.dat myotherfile.txt".

Bob Fourer
4...@ampl.com

[renji...@gmail.com]

Hello 

I try to run ampl with python. I try the following command 

os.system('ampl mymodel.mod mydata.dat myotherfile.run' )

myotherfile.run is the ampl command script.

However, I get the error information like

mydata.dat, line 1 (offset 6):

    max_nodenumber is already defined

context:  param  >>> max_nodenumber: <<< =6;

As I want to change dat file at each running, what can I do? 

Many thanks

Best,

Jing Ren

在 2011年6月30日星期四UTC+8上午3时59分35秒，AMPL Optimization写道：

[victor.z...@gmail.com]

Hello Jing,

Make sure that mydata.dat starts with the data command that switches AMPL to the data mode:

  data;

  param max_nodenumber ...

Otherwise AMPL tries to interpret the file as a model file causing the "already defined" error.

  

HTH,

Victor

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[任婧]

Hi Victor

Thank you so much. 

Best,

Jing

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