[2] Since the early 1961s computer systems have been able to simulate real-world dynamic situations, such as the interaction between people in a public building such as an airport terminal.
Models can be used to test the stresses imposed on an engineering structure without risk or construction cost.
Modern uses include weather systems analysis and the effect on our planet Earth due to global warming.
[3] Like all computer programs its analytical and simulation programs are constructed from three general types of statements:[4] Structural statements can make use of the operations of addition, subtraction, multiplication, division, and exponentiation, using the same notation and syntax rules as are used in FORTRAN.
[5] If, for example, the model includes the equation the following statement will be used to define the variables and calculus performed: x=6.0*Y/W+(Z-2.0)**2.0 Random variation to values can be added to some parts of the model to simulate unpredictable behaviour patterns in dynamic wind-loaded structures, such as high-rise buildings or aircraft wing designs.