Initializing help system before first use

# CRASH

Description | Simplex: This determines the type of crash used when the algorithm begins. During the crash procedure, an initial basis is determined which is as close to feasibility and triangularity as possible. A good choice at this stage will significantly reduce the number of iterations required to find an optimal solution. The possible values increase proportionally to their time-consumption.
Type | Integer
Topic areas | LP, Simplex, Bit-vector
Values |
For the primal simplex algorithm the following choices are available:
0 | Turns off all crash procedures.
1 | For singletons only (one pass).
2 | For singletons only (multi pass).
3 | Multiple passes through the matrix considering slacks.
4 | Multiple (≤ 10) passes through the matrix but only doing slacks at the very end.
>10 | As for value 4 but performing at most n - 10 passes, where n is the specified control value.
For the dual simplex algorithm, the crash control is interpreted as a bit-vector (see Section Bit-vector controls) for adjusting the behavior of the procedure:
Bit | Meaning
0 | Perform standard crash.
1 | Perform additional numerical checks during crash.
2 | Extend the set of column candidates for crash.
3 | Extend the set of row candidates for crash.
4 | Force crash, i.e., consider all suitable columns/rows as candidates for crash.
Default value | 2
Affects routines | XPRSlpoptimize ( LPOPTIMIZE), XPRSmipoptimize ( MIPOPTIMIZE).
Category | Control

Parent Topic Control Parameters

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