[AMPL 18371] Sensitivity Analysis with infeasibility test

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[AMPL 18371] Sensitivity Analysis with infeasibility test

Edwin Okoronkwo
Hello,

I am trying to run the AMPL program in other to do the sensitivity analysis with infeasibility test as described on page 284 of Chapter 14 in the AMPL book but I cannot get it to work. Please see below error that I am getting. Please note that I am not able to enter data interactively. The data has to be entered in the file prior to running the program. Please find attached copy of the files and kindly advise.

Best regards,

Edwin




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diet.mod (566 bytes) Download Attachment
diet.run (734 bytes) Download Attachment
diet2.dat (808 bytes) Download Attachment
dietCommand.run (60 bytes) Download Attachment
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Re: [AMPL 18372] Sensitivity Analysis with infeasibility test

AMPL mailing list
In diet.run you define N as an indexed parameter:

param N {NUTR} symbolic in NUTR;

So in your read statement, it is a syntax error to refer to N without a subscript [ . . . ]. Probably you want to instead define

param N symbolic in NUTR;

--
Robert Fourer
[hidden email]
{#HS:800750866-38392#}
On Wed, Mar 13, 2019 at 12:28 PM UTC, Ampl Modeling Language <[hidden email]> wrote:
Hello,

I am trying to run the AMPL program in other to do the sensitivity analysis with infeasibility test as described on page 284 of Chapter 14 in the AMPL book but I cannot get it to work. Please see below error that I am getting. Please note that I am not able to enter data interactively. The data has to be entered in the file prior to running the program. Please find attached copy of the files and kindly advise.

Best regards,

Edwin

image.png



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Re: [AMPL 18374] Sensitivity Analysis with infeasibility test

Edwin Okoronkwo
Dear Dr Robert,

Thanks for response. I have removed the indexing. I have the same script in my run file as in Fig 14.1 of page 284. Please find attached. However, when I try to run it, the program does not work. It just keep spinning endlessly until I manually interrupt it. Please kindly advise.

Best regards,

Edwin


Regards,



On Wed, Mar 13, 2019 at 4:17 PM AMPL Google Group <[hidden email]> wrote:
In diet.run you define N as an indexed parameter:

param N {NUTR} symbolic in NUTR;

So in your read statement, it is a syntax error to refer to N without a subscript [ . . . ]. Probably you want to instead define

param N symbolic in NUTR;

--
Robert Fourer
[hidden email]
{#HS:800750866-38392#}
On Wed, Mar 13, 2019 at 12:28 PM UTC, Ampl Modeling Language <[hidden email]> wrote:
Hello,

I am trying to run the AMPL program in other to do the sensitivity analysis with infeasibility test as described on page 284 of Chapter 14 in the AMPL book but I cannot get it to work. Please see below error that I am getting. Please note that I am not able to enter data interactively. The data has to be entered in the file prior to running the program. Please find attached copy of the files and kindly advise.

Best regards,

Edwin

image.png



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Re: [AMPL 18378] Sensitivity Analysis with infeasibility test

AMPL mailing list
You need to do a little debugging here. As a start, you could comment out "option solver_msg 0;" so that you see what is happening in the solver, and you could add "print i;" at the beginning of your for-loop so that you can see why i is not falling to a negative value and terminating the loop. That might immediately suggestion the cause of the problem; but if necessary, for more information you could add this as the last statement in the for-loop:

display N_MAX, N_obj, N_dual;

--
Robert Fourer
[hidden email]
{#HS:800750866-38392#}
On Wed, Mar 13, 2019 at 6:00 PM UTC, Ampl Modeling Language <[hidden email]> wrote:
Dear Dr Robert,

Thanks for response. I have removed the indexing. I have the same script in my run file as in Fig 14.1 of page 284. Please find attached. However, when I try to run it, the program does not work. It just keep spinning endlessly until I manually interrupt it. Please kindly advise.

Best regards,

Edwin


Regards,



On Wed, Mar 13, 2019 at 3:16 PM UTC, AMPL Google Group <[hidden email]> wrote:
In diet.run you define N as an indexed parameter:

param N {NUTR} symbolic in NUTR;

So in your read statement, it is a syntax error to refer to N without a subscript [ . . . ]. Probably you want to instead define

param N symbolic in NUTR;

--
Robert Fourer
[hidden email]


On Wed, Mar 13, 2019 at 12:28 PM UTC, Ampl Modeling Language <[hidden email]> wrote:
Hello,

I am trying to run the AMPL program in other to do the sensitivity analysis with infeasibility test as described on page 284 of Chapter 14 in the AMPL book but I cannot get it to work. Please see below error that I am getting. Please note that I am not able to enter data interactively. The data has to be entered in the file prior to running the program. Please find attached copy of the files and kindly advise.

Best regards,

Edwin

image.png



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