[Ipopt] dead loop problem in Fortran version

余堰山 yuysh0802 at mail.iap.ac.cn
Wed Apr 28 05:51:02 EDT 2010

Hi all,

I am encountering a problem when i use ipot(fortran version). The solver succeeds with some initial guess values,but couldn't stop with some other initial values, even IMAXCPUSEC been set to 300. I think there is a dead loop somewhere, the subroutine CHECK_STOP checking the cpu time missed the bug. Where should I add check_stop to find the dead loop? Any suggestion would be appreciated!

Some basic information about my optimization is as follows:

      parameter  (N = 2041, M = 1)
      parameter  (NLB = 1, NUB = 1)
      real*8 DAT(1)
      integer IDAT(1)
      external EV_F, EV_C, EV_G, EV_A

      data ILB    /   2041  /
      data BNDS_L /  0.0d0 /
      data IUB    /   2041 /
      data BNDS_U / 1.0d0 /     

      NARGS = 1
      ARGS(1) = 1.d-8
      CARGS(1) = 'dtol'
      DAT(1) = 1.d0
      fillinfact = 10.d0

The constraints are: x(1)^2+x(2)^2+.....+x(2040)^2+x(2041)=1, 0<x(2041)<1. Note that x(2041) is a slave variable.

The parameters in PARAMS.DAT are set as follows:
dtoL , 1d-8   
imerit 4  
iquasi 6
iprint 10
imaxiter 50
ifile 1 

Best regards

         Yu Yanshan

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