[SCIP] MIP Pre-solver

[Serge Kruk]

Hello all,

I am trying to write a pre-solver for MIP. I want to confirm the following
(or fix my misunderstanding):
Consider a set simple linear constraints $\sum_i a_{ij} x_j \le b_i$

1. Say that I want to change the coefficients $a_ij$ of a row (to scale,
for example).

I have not seen a simple way to just change the coefficient. Must I delete
the constraint and create a scaled constraint?

2. Say I want to change the variable of a column.  Replacing $x_j$ by $z_j$
and creating another constraint relating the two.

Again, I have not seen a simple way to do this except deleting all
constraints and re-creating all of them.

I trust that I am wrong and someone can enlighten me.

Cheers
Serge





      Serge G. Kruk Ph.D.
      Associate Professor     kruk at oakland.edu
      Department of Mathematics and Statistics <http://www.oakland.edu/math>
      Oakland University <http://www.oakland.edu>,
      Rochester, MI.  48309
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