[Ipopt-tickets] [Ipopt] #234: Bad idea of "std::list<TripletEntry>.sort" in "IpTripletToCSRConverter"

[Ipopt]

#234: Bad idea of "std::list<TripletEntry>.sort" in "IpTripletToCSRConverter"
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  Reporter:  galago       |      Owner:  ipopt-team
      Type:  enhancement  |     Status:  new
  Priority:  high         |  Component:  Ipopt
   Version:  3.11         |   Severity:  normal
Resolution:               |   Keywords:  CSRConverter
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Changes (by stefan):

 * severity:  critical => normal


Comment:

 Thank you for your analysis.
 I agree that the sort function of a list may not be as efficient as for an
 randomly accessible container.

 However, I would prefer to avoid larger changes to the code, so all I
 committed for now was to replace std::list by std::vector (r2487). This
 should give you a similar speedup as by your changes. The sorting
 algorithm will do more copying, as it will copy complete triplets instead
 of single integers. On the other hand, I could avoid the extra arrays
 idx_sort, ia_sorted, ja_sorted, and ia_tri.

 r2488 removes the implementation of the copy constructor and assignment
 operator for the !TripletEntry class, so the defaults are used. Maybe that
 makes this a bit faster (?).

 Maybe you can rerun your analysis with these changes.

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Ticket URL: <https://projects.coin-or.org/Ipopt/ticket/234#comment:2>
Ipopt <http://projects.coin-or.org/Ipopt>
Interior-point optimizer for nonlinear programs.