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;
ampl
asked Dec 31 '18 at 18:52
AnakhandAnakhand
309110
add a comment |
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;
ampl
asked Dec 31 '18 at 18:52
AnakhandAnakhand
309110
add a comment |
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;
ampl
asked Dec 31 '18 at 18:52
AnakhandAnakhand
309110
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;
ampl
ampl
asked Dec 31 '18 at 18:52
AnakhandAnakhand
309110
asked Dec 31 '18 at 18:52
AnakhandAnakhand
309110
asked Dec 31 '18 at 18:52
AnakhandAnakhand
309110
asked Dec 31 '18 at 18:52
AnakhandAnakhand
309110
asked Dec 31 '18 at 18:52
AnakhandAnakhand
309110
309110
add a comment |
add a comment |
1 Answer
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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.
answered Dec 31 '18 at 21:53
Geoffrey BrentGeoffrey Brent
93789
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
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.
answered Dec 31 '18 at 21:53
Geoffrey BrentGeoffrey Brent
93789
add a comment |
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.
answered Dec 31 '18 at 21:53
Geoffrey BrentGeoffrey Brent
93789
add a comment |
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.
answered Dec 31 '18 at 21:53
Geoffrey BrentGeoffrey Brent
93789
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.
answered Dec 31 '18 at 21:53
Geoffrey BrentGeoffrey Brent
93789
answered Dec 31 '18 at 21:53
Geoffrey BrentGeoffrey Brent
93789
answered Dec 31 '18 at 21:53
Geoffrey BrentGeoffrey Brent
93789
answered Dec 31 '18 at 21:53
Geoffrey BrentGeoffrey Brent
93789
93789
add a comment |
add a comment |
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