The Cold Start option controls the linear solver that is used by the branch-and-bound solver at each node of the solution tree when a previous solution is not present to use as a "warm start". The Warm Start option, duscussed above, determines the solver to use when a previous solution does exist.

If you pull down the drop-down box for Cold Start, you’ll find the following:

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The available options are:

LINGO Decides – LINGO chooses the most appropriate solver at each node.
Barrier – LINGO uses the barrier method, assuming you have purchased a license for the barrier solver. Otherwise the dual solver will be used.
Primal  – LINGO uses the primal solver exclusively.
Dual – LINGO uses the dual solver exclusively.

In general, LINGO Decides will yield the best results. However, experimentation with the other options may be fruitful.