[Ipopt] A small bug

[Stefan Vigerske]

Hi,

I cannot reproduce this issue.
If all variables are fixed, the code should not even get to the place 
you show in your stacktrace.
In DefaultIterateInitializer::SetInitialIterates(), the call to
IpData().InitializeDataStructures() just at the beginning (line 194) 
should throw an exception, so that it doesn't get to line 278 
(iterates->z_L_NonConst()->ElementWiseDivide(*IpCq().trial_slack_x_L())).

The exception is thrown by IpTNLPAdapter.cpp:684,

         if (status == SUCCESS) {
           jnlst_->Printf(J_WARNING, J_INITIALIZATION,
                          "All variables are fixed and constraint 
violation %e\n   is below tolerance %e. Declaring success.\n", max_viol, 
tol_);

and catched again in IpIpoptApplication.cpp:1048 (end of 
IpoptApplication::call_optimize()).

Can you specify more which Ipopt version you are using and which interface?

Stefan

On 11/08/2013 08:48 AM, darknesswind wrote:
> When I run the solver on a problem with all fixed variables, I found the DenseVector "ip_data_->curr()->z_L()" is uninitialized in function IpoptCalculatedQuantities::trial_slack_x_L.It may cause a crash in release version because of access violation.
>
> The problem is:
> y = x1 * x2
> subject to:
> x1 * x2 = 0
> x1 = 0
> x2 = 0
>
> Here is the call stack:        The dense_x->homogeneous_ equal to false but the dense_x->values_ is null.
>
>> 	ipopt.dll!Ipopt::DenseVector::ElementWiseDivideImpl(const Ipopt::Vector & x)  Line 240	C++
>   	ipopt.dll!Ipopt::Vector::ElementWiseDivide(const Ipopt::Vector & x)  Line 602 + 0x13 bytes	C++
>   	ipopt.dll!Ipopt::IpoptCalculatedQuantities::CalculateSafeSlack(Ipopt::SmartPtr<Ipopt::Vector> & slack, const Ipopt::SmartPtr<Ipopt::Vector const > & bound, const Ipopt::SmartPtr<Ipopt::Vector const > & curr_point, const Ipopt::SmartPtr<Ipopt::Vector const > & multiplier)  Line 481	C++
>   	ipopt.dll!Ipopt::IpoptCalculatedQuantities::trial_slack_x_L()  Line 365 + 0x5b bytes	C++
>   	ipopt.dll!Ipopt::DefaultIterateInitializer::SetInitialIterates()  Line 278 + 0x16 bytes	C++
>   	ipopt.dll!Ipopt::IpoptAlgorithm::InitializeIterates()  Line 545 + 0x26 bytes	C++
>   	ipopt.dll!Ipopt::IpoptAlgorithm::Optimize(bool isResto)  Line 274	C++
>   	ipopt.dll!Ipopt::IpoptApplication::call_optimize()  Line 860 + 0xd bytes	C++
>   	ipopt.dll!Ipopt::IpoptApplication::OptimizeNLP(const Ipopt::SmartPtr<Ipopt::NLP> & nlp, Ipopt::SmartPtr<Ipopt::AlgorithmBuilder> & alg_builder)  Line 754 + 0x8 bytes	C++
>   	ipopt.dll!Ipopt::IpoptApplication::OptimizeNLP(const Ipopt::SmartPtr<Ipopt::NLP> & nlp)  Line 717 + 0x17 bytes	C++
>   	ipopt.dll!Ipopt::IpoptApplication::OptimizeTNLP(const Ipopt::SmartPtr<Ipopt::TNLP> & tnlp)  Line 696 + 0x16 bytes	C++
>
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