[Coin-discuss] Node and Cuts

[Heesu Hwang]

Hello,
I am doing branch-and-price-and-cut, and have two questions.

1. I found that BCP branches down branch first, i.e., x=0.
Is there some relatively easy way to select nodes without using strong
branching?

2. The cuts in down branch is different from those in the up branch. An
inequality cut in down branch becomes an equality cut with a slack
variable in up branch. I am afraid these different cuts make unexpected
result. Does anyone have an idea, how I can keep the same cuts?

For example,
A cut in down branch (x=0)
 c31: 9784726.5339 x2 + 9922037.7619 x3 + 3847452.3252 x4 + 5263118.2828
x5
      + 11332623.448 x6 + 9913642.4516 x7 + 5827514.227 x8 +
11099349.071 x9
      + 7427321.2224 x10 + 3580677.5903 x11 + 3636841.7827 x12
      + 11099349.071 x13 + 9913642.4516 x14 + 15272200.224 x15
      + 4407884.7749 x16 + 3847452.3252 x17 + 9922037.7619 x18
      + 16410240.607 x19 + 2696808.7201 x20 + 10942723.352 x21
      + 8120324.1628 x22 + 16410240.607 x23 + 621987.44862 x24
      + 621987.44862 x25 + 3783651.6151 x26 + 2081646.6981 x27
      + 10000365.379 x28 + 3783651.6151 x29 + 2081646.6981 x30
      + 8517588.3529 x31 + 18648320.904 x32 + 5373995.8791 x33
      + 2029385.5081 x34 + 6769872.1998 x35 + 3847452.3252 x36
      + 6769872.1998 x37 + 5096501.0323 x38 + 3580677.5903 x39
      + 2029385.5081 x40 + 621987.44862 x41 + 5827514.227 x42
      + 16410240.607 x43 + 5373995.8791 x44 + 9922037.7619 x45
      + 5827514.227 x46 + 16410240.607 x47 + 10000365.379 x48
      + 3580677.5903 x49 + 16410240.607 x50 + 10942723.352 x51
      + 11099349.071 x52 <= 74721766.068

is changed to another cut in up branch (x=1)
 c31: 9784726.5339 x2 + 9922037.7619 x3 + 3847452.3252 x4 + 5263118.2828
x5
      + 11332623.448 x6 + 9913642.4516 x7 + 5827514.227 x8 +
11099349.071 x9
      + 7427321.2224 x10 + 3580677.5903 x11 + 3636841.7827 x12
      + 11099349.071 x13 + 9913642.4516 x14 + 15272200.224 x15
      + 4407884.7749 x16 + 3847452.3252 x17 + 9922037.7619 x18
      + 16410240.607 x19 + 2696808.7201 x20 + 10942723.352 x21
      + 8120324.1628 x22 + 16410240.607 x23 + 621987.44862 x24
      + 621987.44862 x25 + 3783651.6151 x26 + 2081646.6981 x27
      + 10000365.379 x28 + 3783651.6151 x29 + 2081646.6981 x30
      + 8517588.3529 x31 + 18648320.904 x32 + 5373995.8791 x33
      + 2029385.5081 x34 + 6769872.1998 x35 + 3847452.3252 x36
      + 6769872.1998 x37 + 5096501.0323 x38 + 3580677.5903 x39
      + 2029385.5081 x40 + 621987.44862 x41 + 5827514.227 x42
      + 16410240.607 x43 + 5373995.8791 x44 + 9922037.7619 x45
      + 5827514.227 x46 + 16410240.607 x47 + 10000365.379 x48
      + 3580677.5903 x49 + 16410240.607 x50 + 10942723.352 x51
      + 11099349.071 x52 - Rgc31  = -1e+20

Regards,

Heesu.