[Ipopt-tickets] [Ipopt] #83: Compiler error in IpTripletToCSRConverter.cpp using MinGW g++ 4.3.0

[Ipopt]

#83: Compiler error in IpTripletToCSRConverter.cpp using MinGW g++ 4.3.0
------------------------------+---------------------------------------------
Reporter:  guest              |       Owner:  ipopt-team
    Type:  defect             |      Status:  new       
Priority:  normal             |   Component:  Ipopt     
 Version:  3.5 (C++ Version)  |    Severity:  normal    
Keywords:                     |  
------------------------------+---------------------------------------------
 When compiling IpTripletToCSRConverter.cpp in the
 Algorithm/LinearSolvers directory, I get the following error message:


 {{{
 IpTripletToCSRConverter.cpp:63:   instantiated from here
 IpTripletToCSRConverter.hpp:105: error: 'void
 Ipopt::TripletToCSRConverter::TripletEntry::operator=(const
 Ipopt::TripletToCSRConverter::TripletEntry&)' is private
 }}}

 -----

 This is the failing code line in IpTripletToCSRConverter.cpp:


 {{{
     std::list<TripletEntry> entry_list(nonzeros);
 }}}

 The TripletEntry assignment operator is declared private in
 IpTripletToCSRConverter.hpp. I notice in the code there is a public
 dummy copy constructor for the inner class TripletEntry, and I assume
 that this copy constructor is defined to make the TripletEntry list
 construction possible. But it seems like the std::list implementation in
 GCC 4.3.0 uses the assignment operator, hence the compilation failure.
 (I have not verified this, but it seems plausible to me.)

 From what I can tell, the TripletEntry class is local to the
 TripletToCSRConverter class, and the data members in TripletEntry are
 simple integers (typedef int Index). Then, would it not be OK to let the
 compiler implicitly define both the copy constructor and the assignment
 operator? That is, remove the definition "TripletEntry(const
 TripletEntry&)" and the declaration "void operator=(const
 TripletEntry&)" from the TripletEntry class? With these modifications,
 the code compiles flawlessly, and the optimizer seems to run as
 intended.

 / Anders Gustafsson (anders dot 9ustafsson at gmail dot com)

-- 
Ticket URL: <https://projects.coin-or.org/Ipopt/ticket/83>
Ipopt <http://projects.coin-or.org/Ipopt>
Interior-point optimizer for nonlinear programs.