[SCIP] Fwd: pricing in problem variables

[Gerald Gamrath]

Hi James,

sorry for the late reply. Your explanation with the cuts sounds 
reasonable and could well cause this behavior, but is not the reason 
here, since the cuts are only added a bit later.
I also needed to have a look in the code to find the cause, but in the 
end, it's quite simple: SCIP does not print a display line after each 
pricing round, but only if nrounds % 100 == 1 (and after the pricing 
round is finished, after cutting, etc.). So, the second line you see is 
after a few more pricing rounds and you end up at 30.000 variables at 
that point even if only 2000 are added each round.

Best,
Gerald

Am 15.05.2017 um 11:55 schrieb James Cussens:
> Hi folks,
>
> Regarding my question below. I suspect now that the reason I end up 
> with so many new columns is that the relevant variables are in the 
> cuts I am adding. Does that make sense?
>
> James
>
>
> ---------- Forwarded message ----------
> From: *James Cussens* <james.cussens at york.ac.uk 
> <mailto:james.cussens at york.ac.uk>>
> Date: 12 May 2017 at 15:13
> Subject: pricing in problem variables
> To: scip at zib.de <mailto:scip at zib.de>
>
>
> I am experimenting with setting my problem variables to be non-initial 
> and having them 'priced-in'. See  below for an example of what is 
> going on.
>
> The line where we get 2000 cols makes sense, since this is the 
> (default) value of pricing/maxvarsroot = 2000. However on the next 
> iteration we end up with ~30k columns.
> I don't see why we don't just end up with 4000. Can anyone illuminate me?
>
> Note that since I have also marked my variables as 'removable' most of 
> them get (perhaps temporarily) removed a little later on.
>
> James
>
> .....
> 1 constraints of type <dagcluster>
> Presolving Time: 14.87
>
>  time | node  | left  |LP iter| mem |depth|mdpt |frac |cons |cols 
> |rows |cuts |pool |confs|strbr|  dualbound   | primalbound  |  gap
>  16.6s|     1 |     0 |     2 | 249M|   0 |   0 |   - |1275 |2000 | 
>  23 |   0 |   0 |   0 |   0 | 0.000000e+00 |      --      |  Inf
>  16.7s|     1 |     0 |    23 | 250M|   0 |   0 |   0 |1275 |  30k| 
>  23 |   0 |   0 |   0 |   0 |-6.120109e+04 |      --      |  Inf
> k16.8s|     1 |     0 |    23 | 250M|   0 |   0 |   0 |1275 |  30k| 
>  23 |   0 |   0 |   0 |   0 |-6.120109e+04 |-8.017084e+04 |  31.00%
>  17.1s|     1 |     0 |   210 | 261M|   0 |   0 |   0 |1275 |  30k| 
> 149 | 126 |   8 |   0 |   0 |-6.120109e+04 |-8.017084e+04 |  31.00%
>  17.2s|     1 |     0 |   210 | 261M|   0 |   0 |   0 |1275 |  30k| 
> 149 | 126 |   8 |   0 |   0 |-6.396899e+04 |-8.017084e+04 |  25.33%
>  18.1s|     1 |     0 |   444 | 288M|   0 |   0 |  58 |1275 |  30k| 
> 288 | 265 |   9 |   0 |   0 |-6.396899e+04 |-8.017084e+04 |  25.33%
>  18.3s|     1 |     0 |   463 | 288M|   0 |   0 |  55 |1275 |  30k| 
> 288 | 265 |   9 |   0 |   0 |-6.566947e+04 |-8.017084e+04 |  22.08%
> k18.4s|     1 |     0 |   463 | 288M|   0 |   0 |  55 |1275 |  30k| 
> 288 | 265 |   9 |   0 |   0 |-6.566947e+04 |-7.959231e+04 |  21.20%
>  19.9s|     1 |     0 |  1144 | 299M|   0 |   0 | 136 |1275 |  30k| 
> 366 | 343 |  10 |   0 |   0 |-6.566947e+04 |-7.959231e+04 |  21.20%
>  20.4s|     1 |     0 |  1211 | 299M|   0 |   0 | 152 |1275 |  30k| 
> 366 | 343 |  10 |   0 |   0 |-6.640382e+04 |-7.959231e+04 |  19.86%
>  22.1s|     1 |     0 |  1782 | 301M|   0 |   0 | 207 |1275 |  30k| 
> 442 | 419 |  11 |   0 |   0 |-6.640382e+04 |-7.959231e+04 |  19.86%
>  22.7s|     1 |     0 |  1851 | 301M|   0 |   0 | 221 |1275 |  30k| 
> 442 | 419 |  11 |   0 |   0 |-6.643694e+04 |-7.959231e+04 |  19.80%
> k22.8s|     1 |     0 |  1851 | 301M|   0 |   0 | 221 |1275 |  30k| 
> 442 | 419 |  11 |   0 |   0 |-6.643694e+04 |-7.919237e+04 |  19.20%
>  24.3s|     1 |     0 |  2116 | 416M|   0 |   0 | 197 |1275 | 525 | 
> 416 | 469 |  38 |   0 |   0 |-6.643694e+04 |-7.919237e+04 |  19.20%
> ....
>
>
> -- 
> James Cussens
> Dept of Computer Science &
> York Centre for Complex Systems Analysis
> Room 326, The Hub, Deramore Lane            Tel +44 (0)1904 325371 
> <tel:+44%201904%20325371>
> University of York    Fax +44 (0)1904 500159 <tel:+44%201904%20500159>
> York YO10 5GE, UK http://www.cs.york.ac.uk/~jc 
> <http://www.cs.york.ac.uk/%7Ejc>
> http://www.york.ac.uk/docs/disclaimer/email.htm 
> <http://www.york.ac.uk/docs/disclaimer/email.htm>
>
>
>
> -- 
> James Cussens
> Dept of Computer Science &
> York Centre for Complex Systems Analysis
> Room 326, The Hub, Deramore Lane            Tel    +44 (0)1904 325371
> University of York                                        Fax  +44 
> (0)1904 500159
> York YO10 5GE, UK http://www.cs.york.ac.uk/~jc 
> <http://www.cs.york.ac.uk/%7Ejc>
> http://www.york.ac.uk/docs/disclaimer/email.htm
>
>
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