[Coin-symphony] warmstarting

Goehring lutz.goehring at uni-hohenheim.de
Mon Feb 19 13:14:21 EST 2007


Hi everyone,

I am solving a MILP keeping the warm start manipulationg the objective
function and solving from warm start. This used to wrok fine. But now
the objective value does not change any more. 

Has the warmstarting routine changed?

Parameters are set as the following:

    setSymParam(OsiSymKeepWarmStart,true);
    setSymParam(OsiSymDoReducedCostFixing,false);

Here is the output of my program:
------------------------------------

mipSolver->getObjCoefficients()[3]-3.06
mipSolver->getObjCoefficients()[14]4
Solving...

****************************************************
* Now processing NODE 0 LEVEL 0 (from TM)
****************************************************

Diving set to 2



**** Starting iteration 1 ****

The LP value is: 17527.748 [0,89]

Now displaying the relaxed solution ...
Receiving/creating cuts...

Cuts in the local pool: 2

Number of cuts added to the problem: 2

In iteration 1, before calling branch()
... 2 violated cuts were added
Continue with this node. 2 cuts added alltogether in iteration 1



**** Starting iteration 2 ****

The LP value is: 17527.748 [0,2]

Now displaying the relaxed solution ...
Row effectiveness: rownum: 104 ineff: 0 deletable: 0

Receiving/creating cuts...

Cuts in the local pool: 0


In iteration 2, before calling branch()
... no cuts were added.
Now displaying final relaxed solution...

[17464.416, 0,1]  [17527.748, 0,4]
Decided to dive...
*************************************************
* Now processing NODE 2 LEVEL 1
*************************************************



**** Starting iteration 3 ****

The LP value is: 17527.748 [0,0]


****** Found Better Feasible Solution !
****** Cost: 17527.748238

fathoming node (no more cols to check)

++++++++++++++++++++++++++++++++++++++++++++++++++
+ TM: Pruning NODE 1 LEVEL 1 instead of sending it.
++++++++++++++++++++++++++++++++++++++++++++++++++

****************************************************
* Optimal Solution Found                           *
* Now displaying stats and best solution found...  *
****************************************************

======================= CP Timing ===========================
  Cut Pool                  0.000
====================== LP/CG Timing =========================
  LP Solution Time          0.011
  Variable Fixing           0.000
  Pricing                   0.000
  Strong Branching          0.004
  Separation                0.014
  Total User Time              0.029
  Total Wallclock Time         0.031

====================== Statistics =========================
Number of created nodes :       3
Number of analyzed nodes:       2
Depth of tree:                  1
Size of the tree:               3
Number of Chains:               1
Number of Diving Halts:         0
Number of cuts in cut pool:     0
Upper Bound in Root:            17527.748

Solution Found: Node 2, Level 1
Solution Cost: 17527.748
+++++++++++++++++++++++++++++++++++++++++++++++++++
User indices and values of nonzeros in the solution
+++++++++++++++++++++++++++++++++++++++++++++++++++
      4    728.390
      9    110.100
     10      3.000
     11      8.601
     14    380.222
     27     20.000
     28     20.000
     29     20.000
     30     20.000
     31     20.000
     32     20.000
     33     20.000
     34     20.000
     35     20.000
     36     20.000
     37     20.000
     38     20.000
     45      0.826
     46     34.598
     47     20.000
     48     20.000
     49     38.616
     50     53.519
     51    139.000
     52    139.000
     53    139.000
     54    108.625
     55    129.666
     56     58.584
     57     30.097
     58    600.000
     59      3.000
     83     10.000
     84      1.000
    159      0.277
    183      0.469
    205      0.357
    210      0.669
    214      0.248
    225      2.411
    231      1.266
    232      1.075
    233   2507.884
    234   1130.479
    235   1505.256
    236    456.777
    237   1505.256
    238  14792.563

solution.getObjCoefficients()[3]-3.06
solution.getObjCoefficients()[14]4
ObjValue with SYMPHONY: 17527.748238
mipSolver->getObjCoefficients()[3]-1.2
mipSolver->getObjCoefficients()[14]-8
Solving...


****************************************************
* Optimal Solution Found                           *
* Now displaying stats and best solution found...  *
****************************************************

======================= CP Timing ===========================
  Cut Pool                  0.000
====================== LP/CG Timing =========================
  LP Solution Time          0.000
  Variable Fixing           0.000
  Pricing                   0.000
  Strong Branching          0.000
  Separation                0.000
  Total User Time              0.000
  Total Wallclock Time         0.000

====================== Statistics =========================
Number of created nodes :       3
Number of analyzed nodes:       2
Depth of tree:                  1
Size of the tree:               3
Number of Chains:               1
Number of Diving Halts:         0
Number of cuts in cut pool:     0
Upper Bound in Root:            17527.748

Solution Found: Node 2, Level 1
Solution Cost: 17527.748
+++++++++++++++++++++++++++++++++++++++++++++++++++
User indices and values of nonzeros in the solution
+++++++++++++++++++++++++++++++++++++++++++++++++++
      4    728.390
      9    110.100
     10      3.000
     11      8.601
     14    380.222
     27     20.000
     28     20.000
     29     20.000
     30     20.000
     31     20.000
     32     20.000
     33     20.000
     34     20.000
     35     20.000
     36     20.000
     37     20.000
     38     20.000
     45      0.826
     46     34.598
     47     20.000
     48     20.000
     49     38.616
     50     53.519
     51    139.000
     52    139.000
     53    139.000
     54    108.625
     55    129.666
     56     58.584
     57     30.097
     58    600.000
     59      3.000
     83     10.000
     84      1.000
    159      0.277
    183      0.469
    205      0.357
    210      0.669
    214      0.248
    225      2.411
    231      1.266
    232      1.075
    233   2507.884
    234   1130.479
    235   1505.256
    236    456.777
    237   1505.256
    238  14792.563

solution.getObjCoefficients()[3]-1.2
solution.getObjCoefficients()[14]-8
ObjValue with SYMPHONY: 17527.748238
----------------------------------

Thanks,

Lutz


-- 
Lutz Göhring
Scientific Assistant

with Prof. Thomas Berger

Professur (i.V.) für Ökonomik der Landnutzung in den Tropen und Subtropen
(Professorship (p.p.) for Land Use Economics in the Tropics and
Subtropics)
Institute for Agricultural Economics and Social Sciences in the Tropics
and Subtropics, 
University of Hohenheim, Stuttgart

e-mail: lutz.goehring at uni-hohenheim.de
Tel.: +49-711-459-23615
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