[AMPL 24908] AMPL shows me this: Could not find "".

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1

Hello, I´m trying to model a problem in AMPL with Baron;

But when I run the model, this is the result

BARON 23.3.11 (2023.03.11):

Could not find “”.

Could not find “”.

0 iterations, optimal within tolerances.

Objective 0

Any idea why this is happen?

Here is the code of the problem

set pol; #Objetos

set ver =1…4; #Vertices

param I:=3;

set vert{2…I} within ver;

param area {pol}>=0;

variables

var r >=0;

var X {k in pol, j in ver};

var Y {k in pol, j in ver};

var A {k in pol, l in pol};

var B {l in pol, k in pol};

var Vx {k in pol, j in ver};

var Vy {k in pol, j in ver};

minimize obj: r;

#Objeto

s.t. Rad{k in pol, j in ver}: X[k,j]^2+Y[k,j]<=r^2;

s.t. la1{k in pol, j in 2…I}: ((X[k,j-1]-X[k,j])(Y[k,j-1]-Y[k,j]))+((X[k,j]-X[k,j+1])(Y[k,j]-Y[k,j+1]))=0;

s.t. la2{k in pol}: ((X[k,4]-X[k,3])(Y[k,4]-Y[k,3]))+((X[k,1]-X[k,4])(Y[k,1]-Y[k,4]))=0;

s.t. are{k in pol}:((X[k,4]-X[k,3])^2 + (Y[k,2]-Y[k,1])^2) * ((X[k,3]-X[k,2]^2) + (Y[k,3]-Y[k,2])^2)==area[k]**2;

Greetings

2

Given only the information that you have provided, I have not been able to exactly reproduce your error messages. To get more help, you’ll need to provide also the data for the model.

If you set any options for BARON, then also include the option string or listing that you used.

3

Here’s all files from the model

ModG.mod (1.04 KB)

ModG.dat (120 Bytes)

ModG.run (119 Bytes)

4

Sorry, here’s all the data, I added more code but same error

ModG.mod (1.04 KB)

ModG.dat (120 Bytes)

ModG.run (102 Bytes)

5

I am not seeing any error messages when I execute ModG.run on my computer:

ampl: include ModG.run;
BARON 23.3.11 (2023.03.11): 0 iterations, optimal within tolerances.
Objective 0

ampl: display _varname, _var;
:    _varname       _var       :=
1    r             0
2    'X[1,1]'      0
3    'X[1,2]'      1
4    'X[1,3]'      1.1727
5    'X[1,4]'      1.4175
6    'X[2,1]'      2.1032
7    'X[2,2]'     -1.16572
8    'X[2,3]'      2.18376
9    'X[2,4]'     -2.22046
10   'Y[1,1]'     -3.80619
11   'Y[1,2]'     -2.99452
12   'Y[1,3]'     -7.69438
13   'Y[1,4]'     -4.37879
14   'Y[2,1]'     -5.17345
15   'Y[2,2]'     -5.17345
16   'Y[2,3]'     -5.17345
17   'Y[2,4]'     -5.17345
18   'A[1,1]'      3.36632
19   'A[1,2]'      4.71849
20   'A[2,1]'      6.79761
21   'A[2,2]'      6.27885
22   'B[1,1]'     -4.77927
23   'B[1,2]'     -7.51784
24   'B[2,1]'    -10.3926
25   'B[2,2]'     -7.58207
26   'Vx[1,1]'    -0.984735
27   'Vx[1,2]'    -0.982566
28   'Vx[2,1]'    -0.555897
29   'Vx[2,2]'    -0.614571
30   'Vy[1,1]'     0.174063
31   'Vy[1,2]'    -0.185912
32   'Vy[2,1]'    -0.831251
33   'Vy[2,2]'    -0.788861
;

I did find a similar message, when incorrectly setting a local solver for BARON to use:

ampl: option baron_options 'lsolver=';
ampl: solve;
BARON 23.3.11 (2023.03.11): lsolver=
Cannot find ""; ignoring lsolver.
BARON 23.3.11 (2023.03.11): 0 iterations, optimal within tolerances.
Objective 0

Here are some things you might check:

  • Are you trying to use a subsolver or an options file, which perhaps BARON cannot find?
  • I ran my tests on Windows. Are you using a different operating system? Maybe the “Could not find” messages only appear on a certain platform.
  • When you run BARON, after the “Could not find” messages, it reports “0 iterations, optimal within tolerances. Objective 0” – just like on my computer. If you execute “display _varname, _var;” after solving, do you see the same results that I have shown above?
6

The option of display _ varname, _var works.
Thanks alot!
Happy Holidays!

7

Good! For other ways to use the “display” command, see Chapter 12 Display Commands in the AMPL book.