CODEWITHSUNDEEP
ampl
Anakhand
Anakhand

Reputation: 2998

Temporary variable in AMPL

Is there a way in AMPL to declare and use temporary variables? What I mean by that is the "regular" variables used in programming (instead of model variables), especially in the .run file, such as saving a string for repeated use in the .run file:

some_file = sprintf(foo%u.txt, 3);  # Temporary variable
print "Hello World" > some_file;
print "Hello again" > some_file;

Upvotes: 1

Views: 265

Answers (1)

G_B
G_B

Reputation: 1573

If it's not variable within the optimisation that you're going to solve, then it's a parameter. You can change the parameter value with let, like so:

reset;
param blah symbolic;
let blah := "hello world";
print blah;
let blah := "this parameter has changed";
print blah;

Parameters in AMPL are number by default; string params need to be explicitly declared as symbolic.

Note that I've declared the param in a separate statement from the first assignment. If I were to assign a value in the declaration, like param blah symbolic := "hello world";, then it would fail when I try to change the value.

Upvotes: 1

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