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FlexPDE can perform automated parameter studies through use of the STAGE facility.  In this mode, FlexPDE will run the problem a number of times, with differing parameters in each run.  Each STAGE begins with the solution and mesh of the previous STAGE as initial conditions.

HISTORY plots can be used to show the variation of scalar values as the STAGES proceed.

Note: The STAGE facility can only be used on steady-state problems. It cannot be used with time dependent problems.

 

The STAGES Selector

In the SELECT section, the statement
 

STAGES = number
 

specifies that the problem will be run number times.  A parameter named STAGE is defined, which takes on the sequence count of the staged run.  Other definitions may use this value to vary parameter values, as for example:
 

Voltage = 100*stage

 

STAGED Definitions

A parameter definition may also take the form:
 

param = STAGED ( value_1, value_2, ... value_n )
 

In this case, the parameter param takes on value_1 in stage 1, value_2 in stage 2, etc.

If STAGED parameters are defined, the STAGES selector is optional.  If the STAGES selector is not defined, the length of the STAGED list will be used as the number of stages.  If the STAGES selector is defined, it overrides the length of the STAGED list. Commas are optional.

 

See the example "Samples | Usage | Stages.pde".

 

STAGED Definitions by incrementation

Any value in the STAGED form above may be replaced by the incrementation form
 

value_i BY increment TO value_j
 

 

STAGED Geometry

If the geometric domain definition contains references to staged quantities, then the solution and mesh will not be retained, but the mesh will be regenerated for the new geometry.  History plots can still be displayed for staged geometries.

 

See the example "Samples | Usage | Staged_Geometry.pde".

 

FlexPDE attempts to detect stage dependence in the geometrical domain definition and automatically regenerate the mesh.  If for any reason these dependencies are undetected, the global selector STAGEGRID can be used to force grid staging.

 

Note: Scripts with staged geometry will reparse the script file and regenerate any CONST values.