GAMS — The Solver Manuals - Available Software

82 COIN-OR
linear_solver pardiso
pardiso_library /my/path/to/the/pardisolib/mypardisolib.so
tells Ipopt to use the linear solver PARDISO from the library mypardisolib.so under the specified path.
PARDISO is available as compiled shared library for several platforms at http://www.pardiso-project.org.
Note that it is your responsibility to ensure that you are entitled to download and use this package!
5.4 Output
This section describes the standard Ipopt console output. The output is designed to provide a quick summary of
each iteration as Ipopt solves the problem.
Before Ipopt starts to solve the problem, it displays the problem statistics (number of nonzero-elements in the
matrices, number of variables, etc.). Note that if you have fixed variables (both upper and lower bounds are equal),
Ipopt may remove these variables from the problem internally and not include them in the problem statistics.
Following the problem statistics, Ipopt will begin to solve the problem and you will see output resembling the
following,
iter objective inf_pr inf_du lg(mu) ||d|| lg(rg) alpha_du alpha_pr ls
0 1.6109693e+01 1.12e+01 5.28e-01 0.0 0.00e+00 - 0.00e+00 0.00e+00 0
1 1.8029749e+01 9.90e-01 6.62e+01 0.1 2.05e+00 - 2.14e-01 1.00e+00f 1
2 1.8719906e+01 1.25e-02 9.04e+00 -2.2 5.94e-02 2.0 8.04e-01 1.00e+00h 1
and the columns of output are defined as
iter The current iteration count. This includes regular iterations and iterations while in restoration phase. If
the algorithm is in the restoration phase, the letter r’ will be appended to the iteration number.
objective The unscaled objective value at the current point. During the restoration phase, this value remains
the unscaled objective value for the original problem.
inf pr The scaled primal infeasibility at the current point. During the restoration phase, this value is the primal
infeasibility of the original problem at the current point.
inf du The scaled dual infeasibility at the current point. During the restoration phase, this is the value of the
dual infeasibility for the restoration phase problem.
lg(mu) log 10 of the value of the barrier parameter mu.
‖d‖ The infinity norm (max) of the primal step (for the original variables x and the internal slack variables s).
During the restoration phase, this value includes the values of additional variables, p and n.
lg(rg) log 10 of the value of the regularization term for the Hessian of the Lagrangian in the augmented system.
alpha du The stepsize for the dual variables.
alpha pr The stepsize for the primal variables.
ls The number of backtracking line search steps.
When the algorithm terminates, IPOPT will output a message to the screen based on the return status of the
call to Optimize. The following is a list of the possible output messages to the console, and a brief description.
Optimal Solution Found.
This message indicates that IPOPT found a (locally) optimal point within the desired tolerances.