[Ipopt] Getting 'has no member' error for added member function to get primal variables out of C++ ipopt object

[Stefan Vigerske]

Hi,

because mynlp is a pointer to TNLP, which doesn't have a getvalue() 
function.
Try either something like ((NS071_NLP*)GetRawPtr(mynlp))->getvalue() or
let mynlp be a pointer to a NS071_NLP:
   SmartPtr<NS071_NLP> mynlp = new HS071_NLP();

Stefan

On 08/29/2017 04:06 PM, Alexander Martinez-Marchese wrote:
> Hi,
> 
>      I would like to optimize a problem in C++ for different problem settings inside a loop. For that I need to get the primal variables outside of the NS071_NLP object (I kept the same name used in the C++ example). I attached a Rosenbrock problem example using the C++ ipopt interface showing the issue.
> 
> In the C++ example there is a parent (base) class TNLP and all its functions are instantiated in the NS071_NLP using virtual functions.
> 
> I didn't find any functions in TNLP that give you the optimized values. Are there any? So what I tried for a test was to add a function to NS071_NLP called getvalue() {return thevalue;} that gets the first value of the optimized variables (x[]) and added a variable in the NS071_NLP class called double thevalue.
> 
> Then when the finalize_solution(* x, etc) from TNLP is called, the x[] goes into it and I added the line:
> thevalue = x[0];
> 
> After the problem is optimized I try calling mynlp->getvalue() where mynlp is a smart pointer to an NS071_NLP object and I get:
> 
> ipoptexample.cpp: In function ‘int main(int, char**)’:
> ipoptexample.cpp:202:21: error: ‘class Ipopt::TNLP’ has no member named ‘getvalue’; did you mean ‘eval_f’?
>     thevalue = mynlp->getvalue();
>                       ^~~~~~~~
> 
> Why doesn't this work? As a last resort I could go and change TNLP and add the function there but I should be able to add functions to the child class.
> 
> 
> Thank you,
> Alex
> 
> 
> 
> 
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