[Ipopt] Null pointer crash

Andreas Waechter andreasw at watson.ibm.com
Tue Feb 2 11:28:28 EST 2010

Hi Kelly,

Have you been able to fix this in the meantime?  I have not seen this 
problem before, and since it is at the heart of the code, it would 
surprise me if you found a bug there.

However, if you can still reproduce this error, I suggest you first check 
your code with a memory checker to make sure there is no issues with 
writing into invalid memory or using unintialized values.  If you can't 
find anything with this, please let us know what options you are using. 
Also, have a look at the output file for a print_level at least 7 and see 
if you see something strange before the error occurs (e.g., did your code 
return false when evaluating any of the problem functions or 



On Mon, 18 Jan 2010, Plett, Kelly wrote:

> Hi all,
> We have been using Ipopt with good success to optimize various black-box
> process models, so thanks to all who have contributed to the project.
> However...
> Recently I have been running into an increasing number of crashes in
> IpoptCalculatedQuantities::curr_d_minus_s() on a null s pointer.  When I
> bump up COIN_IPOPT_CHECKLEVEL to 3, I observe SmartPtr assertions
> starting in IpoptCalculatedQuantities::trial_slack_x_L() because
> ip_data_->trial()->x() is null.  This occurs in AcceptTrialPoint on the
> max_correction = correct_bound_multiplier(...) line with the following
> call stack:
> 	ipopt.dll!_wassert(const wchar_t * expr=0x0f594ea4, const
> wchar_t * filename=0x0f594e40, unsigned int lineno=433)  Line 384
> C
> 	ipopt.dll!Ipopt::SmartPtr<Ipopt::Vector const >::operator*()
> Line 433 + 0x1c bytes	C++
> 	ipopt.dll!Ipopt::IpoptCalculatedQuantities::trial_slack_x_L()
> Line 357 + 0x8 bytes	C++
> 	ipopt.dll!Ipopt::IpoptCalculatedQuantities::trial_compl_x_L()
> Line 1823 + 0xc bytes	C++
>> 	ipopt.dll!Ipopt::IpoptAlgorithm::AcceptTrialPoint()  Line 658 +
> 0x1d bytes	C++
> 	ipopt.dll!Ipopt::IpoptAlgorithm::Optimize(bool isResto=false)
> Line 367	C++
> Being new to the internals of Ipopt, under what conditions will the
> trial x vector be null?  Is there anything specific I should look for in
> the diagnostics that might help me identify the root cause?  Any
> guidance would be greatly appreciated!
> The case in which I am currently observing this behaviour is tiny (one
> variable, one inequality), but I have seen it in larger ones as well.  I
> can reproduce in both Ipopt 3.6.0 and 3.8.1.
> Thanks in advance,
> Kelly
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