# [Coin-ipopt] Problems using Ipopt

Karsten Theissen tbb at math.uni-muenster.de
Thu Apr 15 05:02:37 EDT 2004

```Hallo Ipopt-Team especially Andreas,

as we discussed in Dresden I tried to install Ipopt (first in a 32 Bit
version) and it seemed to be succesfull, because AMPL accepted
ipoptAMPL as a solver an starts to solve the problem. But even for very easy
problems i get a

"Regularization parameter getting too large (a): 1.0E24"

error. Maybe there was an error in the compilation ??

Ciao Karsten

P.S.: Is it too impolite to write the problems in german?? It would make it
much easier???
P.P.S.: Here I send the complete output from AMPL:

ipopt 2.2.0:
******************************************************************************
This program contains IPOPT, a program for large-scale nonlinear optimization.
IPOPT is released as open source under the Common Public License (CPL).
******************************************************************************

Number of variables           :      400
of which are fixed         :        0
Number of constraints         :      299
Number of lower bounds        :       99
Number of upper bounds        :        0
Number of nonzeros in Jacobian:     1092
Number of nonzeros in Hessian :      200
get_scale: No scaling of constraints necessary

ITER     ERR        MU       ||C||     ||D||     ALFA(X)  #LS        F
#cor
0 0.998D+00d 0.100D+00 0.990D+00 0.000D+00 0.000D+00   0  0.30197000D+00
0
0 0.998D+00d 0.200D-01 0.990D+00 0.000D+00 0.000D+00   0  0.30197000D+00
0
Regularization parameter getting too large (a): 1.0E24
1 0.998D+00d 0.990D+00 0.990D+00 0.000D+00 0.000D+00-  0
0.30197000D+00193
Regularization parameter getting too large (a): 1.0E24
solve_barrier: get_step_full returns IERR =  10
mainloop: Error: solve_barrier ends with IERR =  10

Number of iterations taken .............                      1
Final value of objective function is.... 0.3019700000000001D+00

Errors at final point                      (scaled)       (unscaled)
Final maximal constraint violation is... 0.990000D+00    0.990000D+00
Final value for dual infeasibility is... 0.997998D+00    0.997998D+00
Final value of complementarity error is. 0.100000D-01    0.100000D-01

The objective function was evaluated      1 times.
The constraints were evaluated            1 times.

EXIT: Linear system becomes too ill-conditioned

CPU seconds spent in IPOPT and function evaluations =         40.3300

ipopt 2.2.0: Exit code 10. Check IPOPT output for details.

real     1:51.4
user       40.3
sys      1:10.5

```