[Ipopt-tickets] [Ipopt] #205: Error evaluating constraint 2: can't evaluate pow'(0, 0.6).

[Ipopt]

#205: Error evaluating constraint 2: can't evaluate pow'(0,0.6).
---------------------+------------------------
Reporter:  design@…  |      Owner:  ipopt-team
    Type:  defect    |     Status:  new
Priority:  normal    |  Component:  Ipopt
 Version:  3.10      |   Severity:  normal
Keywords:            |
---------------------+------------------------
 I have try to solve the problem
 {{{
 g3 0 1 0        # problem st_e41
 5 2 1 1 1
 2 0
 0 0
 4 0 0
 0 0 0 0
 0 0 0 0 0
 9 1
 0 0
 0 0 0 0 0
 C0
 o0
 o2
 o2
 v2
 o5
 o1
 n1
 v0
 n2
 o5
 o1
 n1
 v3
 n2
 o2
 o1
 n1
 v2
 o5
 o1
 n1
 o2
 v1
 o1
 n1
 o2
 o1
 n1
 v0
 o1
 n1
 v3
 n2
 C1
 o0
 o0
 o0
 o2
 n-200
 o5
 v0
 n0.6
 o2
 n-200
 o5
 v1
 n0.6
 o2
 n-200
 o5
 v2
 n0.6
 o2
 n-300
 o5
 v3
 n0.6
 O0 0
 n0
 r
 1 0.1
 4 0
 b # variables ranges
 0 0.5 1
 0 0.5 1
 0 0.5 1
 0 0.5 1
 0 593.778559847802 900.000000000001
 k4
 2
 4
 6
 8
 J0 4
 0 0
 1 0
 2 0
 3 0
 J1 5
 0 0
 1 0
 2 0
 3 0
 4 1
 G0 1
 4 1
 }}}

 And I have follow output
 {{{
 ******************************************************************************
 This program contains Ipopt, a library for large-scale nonlinear
 optimization.
  Ipopt is released as open source code under the Eclipse Public License
 (EPL).
          For more information visit http://projects.coin-or.org/Ipopt
 ******************************************************************************

 NOTE: You are using Ipopt by default with the MUMPS linear solver.
       Other linear solvers might be more efficient (see Ipopt
 documentation).


 This is Ipopt version 3.10.1, running with linear solver mumps.

 Number of nonzeros in equality constraint Jacobian...:        5
 Number of nonzeros in inequality constraint Jacobian.:        4
 Number of nonzeros in Lagrangian Hessian.............:       10

 Error evaluating constraint 2: can't evaluate pow'(0,0.6).
 }}}

 It seems IPOPT try to evaluate derivation in zero even low range of
 variable is strongly positive... If degree is less then 1 then I have this
 error [[BR]]


 IPOPT Ipopt 3.8.1 has no this problem.

-- 
Ticket URL: <https://projects.coin-or.org/ticket/205>
Ipopt <http://projects.coin-or.org/Ipopt>
Interior-point optimizer for nonlinear programs.