APMonitor

Global Options | Local Options

 Type: Integer, Input/Output
 Default Value: 0
 Description: Cold start model
              0=warm start
              1=cold start
              2=decompose problem

COLDSTART is an initialization mode for an application. It is by default at 0 (no initialization) but can be set to higher levels (1 or 2) to handle cases where initialization of the problem is a key enabler for a successful solution or to reset an application after a failed solution or a period of inactivity. The initialization values are typically taken from a prior solution as stored in t0 files on the server. When COLDSTART>=1, the t0 files are ignored and the initialization values are taken from the APM file, the DBS file, and the CSV file in that order. A value of 1 indicates that all FV, MV, and CV STATUS values are turned off (0) temporarily to reduce the number of degrees of freedom and achieve a feasible, yet suboptimal solution. A value of 2 is a more aggressive initialization where the degrees of freedom are turned off and the sparsity of the problem is analyzed to create a sequence of lower block triangular segments. These segments are solved sequentially and an error is reported if a particular block is infeasible. Therefore, COLDSTART=2 is one method to help identify equations or variables bounds that may be causing an infeasible solution. Once the application is successfully solved with COLDSTART>=1, the value of COLDSTART is automatically reset to 0 for the next solution.

See also AUTO_COLD, BAD_CYCLES, STATUS