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
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.
n>10 
As for value 4 but performing at most n - 10 passes.
Values
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
Note
For the primal simplex algorithm the following choices are available:
Note
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:
Affects routines
XPRSlpoptimize ( LPOPTIMIZE), XPRSmipoptimize ( MIPOPTIMIZE).
Category
Control

Parent Topic Control Parameters

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