VDF

VDF (Various Data File) Format

VDF is a data file format to define some problem data in simple form, e.g., boundary conditions defined by constants or regular algebraic expressions. The structure of the file shows all data types that can be defined through this kind of files. FDF may seem to be too complicated for a large set of problems indeed.
The main principle here is that any information in the file is contained in a line and is defined by a keyword following the rules :

The first line must contain at the first columns the string #VDATA!
All other lines contain keywords and other parameters separated by any number of spaces following FFI rules. The following lines must contain sequences of one keyword and one (or more) parameter :

Sequence

Information

Select prescription of (Dirichlet) boundary conditions

Source

Select prescription of a source (or body force or any volume right-hand side)

Force

Select prescription of a body force (or source or any volume right-hand side)

Flux

Select prescription of a flux (or traction or any surface right-hand side)

Traction

Select prescription of a traction (or flux or any surface right-hand side)

Initial

Select prescription of initial solution (for a time dependent problem or for an iteration process)

DOF

Define a degree of freedom label to prescribe. By default, this value is set to 1

Code

Define the code for which the prescription is active (This is used only when one of the keywords BC, Flux or Traction is active. By default, this value is set to 1

Value

<regex>

Define value to prescribe. This value is given by a regular expression as defined by the package fparser. Note here that a regular expression defines a function f(x,y,z,t) given by any algebraic expression using standard rules. If a regular expression must contain blank spaces then the expression must by quoted by "

EOF

End of File. Anything beyond this keyword will be ignored.

Here is an example of a VDF file :


   #VDATA!
   BC   Code 1   DOF 1   (x+y)*exp(t)
   Source   DOF 2   "sin(x) + cos(y)"
   EOF