The IPOPT derivative checker doesn't pass on the pendulun_swing_up.py example.

[moorepants]

No description provided.

[moorepants]

The derivatives check out for the pendulum id example (vyasarayani2011.py):

(inverted-pendulum-id)moorepants@moorepants-2170p:examples(ipopt-options)$ python vyasarayani2011.py

******************************************************************************
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
******************************************************************************

This is Ipopt version 3.11, running with linear solver ma57.

Starting derivative checker for first derivatives.


No errors detected by derivative checker.

Number of nonzeros in equality constraint Jacobian...:     4990
Number of nonzeros in inequality constraint Jacobian.:        0
Number of nonzeros in Lagrangian Hessian.............:        0

Total number of variables............................:     1001
                     variables with only lower bounds:        0
                variables with lower and upper bounds:        0
                     variables with only upper bounds:        0
Total number of equality constraints.................:      998
Total number of inequality constraints...............:        0
        inequality constraints with only lower bounds:        0
   inequality constraints with lower and upper bounds:        0
        inequality constraints with only upper bounds:        0

iter    objective    inf_pr   inf_du lg(mu)  ||d||  lg(rg) alpha_du alpha_pr  ls
   0  0.0000000e+00 4.14e+01 0.00e+00   0.0 0.00e+00    -  0.00e+00 0.00e+00   0
   1  1.1903185e-02 2.17e-01 1.94e+00 -11.0 1.94e+00    -  1.00e+00 1.00e+00h  1
   2  1.1728822e-02 1.47e-04 1.17e-04 -11.0 2.63e-02    -  1.00e+00 1.00e+00h  1
   3  1.1702217e-02 6.12e-05 8.14e-05 -11.0 1.90e-02    -  1.00e+00 1.00e+00h  1
   4  1.1698152e-02 1.96e-05 6.38e-05 -11.0 1.07e-02    -  1.00e+00 1.00e+00h  1
   5  1.1698096e-02 4.73e-09 1.12e-05 -11.0 1.65e-04    -  1.00e+00 1.00e+00h  1
   6  1.1694455e-02 4.56e-06 4.76e-05 -11.0 4.81e-03    -  1.00e+00 1.00e+00h  1
   7  1.1691997e-02 4.88e-07 3.06e-05 -11.0 1.89e-03    -  1.00e+00 1.00e+00h  1
   8  1.1690086e-02 9.13e-06 9.97e-06 -11.0 5.45e-03    -  1.00e+00 1.00e+00h  1
   9  1.1690088e-02 4.76e-09 3.45e-10 -11.0 1.64e-04    -  1.00e+00 1.00e+00h  1

Number of Iterations....: 9

                                   (scaled)                 (unscaled)
Objective...............:   1.1690088168634035e-02    1.1690088168634035e-02
Dual infeasibility......:   3.4527869365724717e-10    3.4527869365724717e-10
Constraint violation....:   4.7640047462493840e-09    4.7640047462493840e-09
Complementarity.........:   0.0000000000000000e+00    0.0000000000000000e+00
Overall NLP error.......:   4.7640047462493840e-09    4.7640047462493840e-09


Number of objective function evaluations             = 10
Number of objective gradient evaluations             = 10
Number of equality constraint evaluations            = 10
Number of inequality constraint evaluations          = 0
Number of equality constraint Jacobian evaluations   = 10
Number of inequality constraint Jacobian evaluations = 0
Number of Lagrangian Hessian evaluations             = 0
Total CPU secs in IPOPT (w/o function evaluations)   =      3.744
Total CPU secs in NLP function evaluations           =      0.005

EXIT: Optimal Solution Found.
=====================================
Known value of p = 10.0
Identified value of p = 9.96710465642
=====================================

Notice that didn't converge.