Problem Descriptor Structure

 Top  Previous  Next

Problem descriptors organize a problem by breaking it into sections of related items. 

 

Each section is headed by a proper name followed by one or more statements which define the problem. 

 

The permitted section names are:

 

TITLE

- defines the problem title

SELECT

- sets various options and controls

COORDINATES

- defines the coordinate system

VARIABLES

- names the problem variables

DEFINITIONS

- defines ancillary quantities and parameters

INTIAL VALUES

- sets initial values of variables

EQUATIONS

- defines the partial differential equation system

CONSTRAINTS

- defines optional integral constraints

EXTRUSION

- extends the domain to three dimensions

BOUNDARIES

- describes the 2D or projected 3D domain

RESOLVE

- optionally supplements mesh control

FRONT

- optionally supplements mesh control for advancing fronts

TIME

- defines the time domain

MONITORS

- selects interim graphic display

PLOTS

- selects final graphic display

HISTORIES

- selects time-summary displays

END

- identifies the end of the descriptor

 

The number of sections used in a particular problem descriptor can vary, subject only to the requirement that all files must contain a Boundaries section and an End section.

 

While some flexibility exists in the placement of  these sections, it is suggested that the user adhere to the ordering described above. 

 

DEFINITIONS and SELECT can appear more than once. 

 

Because descriptors are dynamically processed from top to bottom, they cannot contain forward references. Definitions may refer to variables and other defined names, provided these variables and names have been defined in a preceding section or previously in the same section.