I am using SCIP solver (with AMPL executable file) in PYOMO for an optimization problem. Unfortunately the output file in .sol format doesn't contain the iterations data. The information available in the solution file is shown below.
SCIP version 6.0.0 [precision: 8 byte] [memory: block] [mode: optimized] [LP solver: SoPlex 4.0.0] [GitHash: 77d3bc8]
Copyright (C) 2002-2018 Konrad-Zuse-Zentrum fuer Informationstechnik Berlin (ZIB)
External codes:
SoPlex 4.0.0 Linear Programming Solver developed at Zuse Institute Berlin (soplex.zib.de) [GitHash: 82cab95]
CppAD 20180000.0 Algorithmic Differentiation of C++ algorithms developed by B. Bell (www.coin-or.org/CppAD)
Ipopt 3.12.12 Interior Point Optimizer developed by A. Waechter et.al. (www.coin-or.org/Ipopt)
ASL AMPL Solver Library developed by D. Gay (www.netlib.com/ampl)
RNING: unknown parameter <output_file>
number of parameters = 2428
non-default parameter settings:
read problem <C:\Users\Wilson\AppData\Local\Temp\tmp1sfv6ovn.pyomo.nl>
============
original problem has 5 variables (0 bin, 0 int, 0 impl, 5 cont) and 3 constraints
solution violates original bounds of variable <_svar[1]> [1,3] solution value <0>
all 1 solutions given by solution candidate storage are infeasible
presolving:
(round 1, fast) 0 del vars, 0 del conss, 0 add conss, 5 chg bounds, 0 chg sides, 0 chg coeffs, 0 upgd conss, 0 impls, 0 clqs
(round 2, fast) 0 del vars, 0 del conss, 2 add conss, 5 chg bounds, 0 chg sides, 0 chg coeffs, 0 upgd conss, 0 impls, 0 clqs
(round 3, fast) 0 del vars, 0 del conss, 2 add conss, 5 chg bounds, 0 chg sides, 0 chg coeffs, 4 upgd conss, 0 impls, 0 clqs
(round 4, fast) 1 del vars, 1 del conss, 2 add conss, 9 chg bounds, 0 chg sides, 0 chg coeffs, 4 upgd conss, 0 impls, 0 clqs
presolving (5 rounds: 5 fast, 1 medium, 1 exhaustive):
1 deleted vars, 1 deleted constraints, 2 added constraints, 9 tightened bounds, 0 added holes, 0 changed sides, 0 changed coefficients
0 implications, 0 cliques
presolved problem has 6 variables (0 bin, 0 int, 0 impl, 6 cont) and 4 constraints
1 constraints of type <abspower>
3 constraints of type <quadratic>
Presolving Time: 0.00
time | node | left |LP iter|LP it/n| mem |mdpt |frac |vars |cons |cols |rows |cuts |confs|strbr| dualbound | primalbound | gap
* 0.0s| 1 | 0 | 9 | - | 587k| 0 | - | 6 | 4 | 6 | 13 | 0 | 0 | 0 | 2.000000e+00 | 2.000000e+00 | 0.00%
0.0s| 1 | 0 | 9 | - | 587k| 0 | - | 6 | 4 | 6 | 13 | 0 | 0 | 0 | 2.000000e+00 | 2.000000e+00 | 0.00%
SCIP Status : problem is solved [optimal solution found]
Solving Time (sec) : 0.01
Solving Nodes : 1
Primal Bound : +1.99999999998750e+00 (1 solutions)
Dual Bound : +1.99999999998750e+00
Gap : 0.00 %
optimal solution found
However this output does not contain iterations data. An example of iteration data using IPOPT solver is shown below.
iter objective inf_pr inf_du lg(mu) ||d|| lg(rg) alpha_du alpha_pr ls
0 2.5371030e+001 1.20e+002 1.11e+001 -1.0 0.00e+000 - 0.00e+000 0.00e+000 0
1 2.5059090e+001 1.09e+002 1.36e+001 -1.0 1.38e+002 - 9.86e-001 9.10e-002h 1
2 2.5312561e+001 9.68e-003 4.92e-001 -1.0 1.11e+002 - 1.00e+000 1.00e+000h 1
3 2.5056729e+001 1.15e-002 4.98e-002 -1.7 2.90e+000 - 1.00e+000 1.00e+000f 1
4 2.5006568e+001 5.10e-004 2.25e-003 -2.5 7.21e-001 - 1.00e+000 1.00e+000h 1
The output displayed above is only a part of the solution file.
Is there any way that I can get this kind of data with SCIP solver? Please let me know if someone has an idea. Thanks.
from Possibility to obtain iterations data in SCIP .sol file
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