GAMS — The Solver Manuals - Available Software

COIN-OR 107
warm start init point: Warm-start for initial point
Indicates whether this optimization should use a warm start initialization, where values of primal and dual
variables are given (e.g., from a previous optimization of a related problem.) The default value for this string
option is ”no”.
Possible values:
• no: do not use the warm start initialization
• yes: use the warm start initialization
warm start mult bound push: same as mult bound push for the regular initializer.
The valid range for this real option is 0 < warm start mult bound push < +inf and its default value is 0.001.
warm start mult init max: Maximum initial value for the equality multipliers.
The valid range for this real option is −inf < warm start mult init max < +inf and its default value is 1·10 +06 .
warm start same structure: Indicates whether a problem with a structure identical to the previous one is
to be solved.
If ”yes” is chosen, then the algorithm assumes that an NLP is now to be solved, whose structure is identical to
one that already was considered (with the same NLP object). The default value for this string option is ”no”.
Possible values:
• no: Assume this is a new problem.
• yes: Assume this is problem has known structure
warm start slack bound frac: same as slack bound frac for the regular initializer.
The valid range for this real option is 0 < warm start slack bound frac ≤ 0.5 and its default value is 0.001.
warm start slack bound push: same as slack bound push for the regular initializer.
The valid range for this real option is 0 < warm start slack bound push < +inf and its default value is 0.001.
6 CoinScip
GAMS/CoinScip brings the MIP solver from the Constrained Integer Programming framework SCIP to the broad
audience of academic GAMS users.
The code is developed at the Konrad-Zuse-Zentrum für Informationstechnik Berlin (ZIB) and has been written
primarily by T. Achterberg. It is distributed under the ZIB Academic License.
For more information we refer to
• the SCIP web site http://scip.zib.de and
• the Ph.D. thesis “Constraint Integer Programming” by Tobias Achterberg, Berlin 2007.
GAMS/CoinScip uses the COIN-OR linear solver CLP from J.J. Forrest as LP solver, see Section 3.
6.1 Model requirements
SCIP supports continuous, binary, and integer variables, but no special ordered sets, semi-continuous or semiinteger
variables (see chapter 17.1 of the GAMS User’s Guide). Branching priorities are supported.