[SCIP] set/vbc/dispsols

[Gotzes, Uwe Dr.]

Hi,

I have a very simple problem and tried to tell scip to apply plain lp-based branch and bound to it.

I have set vbc/dispsols = TRUE to visualize the nodes where solutions are found.

This option results in the two lines 00:00:00.00 P 6 14 and 00:00:00.00 P 5 14 in the vbc-file. (P int int Number of the node, number of the nodes colour.)

I have two questions:
1. Is it possible to figure out the value of the solution found in the respective node from the vbc-file?
2. What is the meaning of the minus sign in the "frac"-column of node 2?


Scip output is:

 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 |     0 |     - | 166k|   0 |   - |   2 |   3 |   2 |   0 |   0 |   0 |   0 |      --      |      --      |    Inf
(node 1) LP relaxation is unbounded (LP 0)
  0.0s|     1 |     0 |     2 |     - | 167k|   0 |   - |   2 |   3 |   2 |   2 |   2 |   0 |   0 |      --      |      --      |    Inf
(node 1) LP relaxation is unbounded (LP 1)
  0.0s|     1 |     0 |     3 |     - | 168k|   0 |   1 |   2 |   3 |   2 |   2 |   3 |   0 |   0 |8.428571e+000 |      --      |    Inf
  0.0s|     1 |     2 |     3 |     - | 168k|   0 |   1 |   2 |   3 |   2 |   2 |   3 |   0 |   0 |8.428571e+000 |      --      |    Inf
  0.0s|     2 |     1 |     3 |   0.0 | 169k|   1 |   - |   2 |   3 |   2 |   2 |   3 |   0 |   0 |8.000000e+000 |      --      |    Inf
  0.0s|     3 |     2 |     5 |   1.0 | 169k|   1 |   1 |   2 |   3 |   2 |   2 |   3 |   0 |   0 |7.500000e+000 |      --      |    Inf
  0.0s|     4 |     3 |     6 |   1.0 | 170k|   2 |   1 |   2 |   3 |   2 |   2 |   3 |   0 |   0 |7.000000e+000 |      --      |    Inf
* 0.0s|     5 |     2 |     7 |   1.0 | 170k|   3 |   - |   2 |   3 |   2 |   2 |   3 |   0 |   0 |7.000000e+000 |4.000000e+000 |  75.00%
* 0.0s|     6 |     0 |     8 |   1.0 | 170k|   3 |   - |   2 |   3 |   2 |   2 |   3 |   0 |   0 |7.000000e+000 |7.000000e+000 |   0.00%

The content of the generated vbc-file:

#TYPE: COMPLETE TREE
#TIME: SET
#BOUNDS: SET
#INFORMATION: STANDARD
#NODE_NUMBER: NONE
00:00:00.00 N 0 1 3
00:00:00.00 I 1 \inode:\t1\idepth:\t0\nvar:\t-\nbound:\t-100000000000000000000.000000
00:00:00.00 P 1 11
00:00:00.00 N 1 2 3
00:00:00.00 I 2 \inode:\t2\idepth:\t1\nvar:\t-\nbound:\t-8.428571
00:00:00.00 I 2 \inode:\t2\idepth:\t1\nvar:\tt_x1 [-0,1e+020] <= 2.000000\nbound:\t-8.000000
00:00:00.00 N 1 3 3
00:00:00.00 I 3 \inode:\t3\idepth:\t1\nvar:\t-\nbound:\t-8.428571
00:00:00.00 I 3 \inode:\t3\idepth:\t1\nvar:\tt_x1 [-0,1e+020] >= 3.000000\nbound:\t-8.428571
00:00:00.00 I 1 \inode:\t1\idepth:\t0\nvar:\t-\nbound:\t-8.428571\nnr:\t1
00:00:00.00 P 1 2
00:00:00.00 I 3 \inode:\t3\idepth:\t1\nvar:\tt_x1 [3,1e+020] >= 3.000000\nbound:\t100000000000000000000.000000\nnr:\t2
00:00:00.00 P 3 2
00:00:00.00 I 3 \inode:\t3\idepth:\t1\nvar:\tt_x1 [3,1e+020] >= 3.000000\nbound:\t100000000000000000000.000000\nnr:\t2
00:00:00.00 P 3 4
00:00:00.00 N 2 4 3
00:00:00.00 I 4 \inode:\t4\idepth:\t2\nvar:\t-\nbound:\t-7.500000
00:00:00.00 I 4 \inode:\t4\idepth:\t2\nvar:\tt_x2 [-0,3] <= 0.000000\nbound:\t-7.500000
00:00:00.00 N 2 5 3
00:00:00.00 I 5 \inode:\t5\idepth:\t2\nvar:\t-\nbound:\t-7.500000
00:00:00.00 I 5 \inode:\t5\idepth:\t2\nvar:\tt_x2 [-0,3] >= 1.000000\nbound:\t-7.000000
00:00:00.00 I 2 \inode:\t2\idepth:\t1\nvar:\tt_x1 [-0,2] <= 2.000000\nbound:\t-7.500000\nnr:\t3
00:00:00.00 P 2 2
00:00:00.00 N 4 6 3
00:00:00.00 I 6 \inode:\t6\idepth:\t3\nvar:\t-\nbound:\t-6.000000
00:00:00.00 I 6 \inode:\t6\idepth:\t3\nvar:\tt_x1 [-0,2] <= 1.000000\nbound:\t-4.000000
00:00:00.00 N 4 7 3
00:00:00.00 I 7 \inode:\t7\idepth:\t3\nvar:\t-\nbound:\t-6.000000
00:00:00.00 I 7 \inode:\t7\idepth:\t3\nvar:\tt_x1 [-0,2] >= 2.000000\nbound:\t-6.000000
00:00:00.00 I 4 \inode:\t4\idepth:\t2\nvar:\tt_x2 [-0,0] <= 0.000000\nbound:\t-6.000000\nnr:\t4
00:00:00.00 P 4 2
00:00:00.00 I 6 \inode:\t6\idepth:\t3\nvar:\tt_x1 [-0,1] <= 1.000000\nbound:\t-4.000000\nnr:\t5
00:00:00.00 P 6 2
00:00:00.00 P 6 14
00:00:00.00 U -4.000000
00:00:00.00 I 5 \inode:\t5\idepth:\t2\nvar:\tt_x2 [1,3] >= 1.000000\nbound:\t-7.000000\nnr:\t6
00:00:00.00 P 5 2
00:00:00.00 P 5 14
00:00:00.00 I 7 \inode:\t7\idepth:\t3\nvar:\tt_x1 [-0,2] >= 2.000000\nbound:\t-6.000000\nnr:\t6
00:00:00.00 P 7 4
00:00:00.00 U -7.000000

Thanks,
Uwe