[Wien] Wien2k Introduction

[Malik]

Hi all,
I have to present some application porting work in a symposium, In my 
work i have used Wien2k as the experiment application and have used 
Wien2k Workflow for porting on the Grid. although i know how to run a 
complete Wien2k workflow but i dont know what the application does actually.

Can someone please give a small introduction about the application, i 
have already checked the Wien2k.at but it was not of much help because i 
am not a student of this field.

Here is what i want:
1.    A small Introduction to Wien2k
2.    What is a case?
3.    What factors decide the complexity of the calculations performed 
by the application
4.    What factor decides the Problem size and number of iterations in 
the workflow.

Many thanks.

Malik