The flow of execution in program mode TSIM follows the arrows indicated in figure:
Input data commands
Program TSIM reads the input data file every time step, and follows the instructions given in the input data commands. The main memory of program TSIM is updated directly for every input data command read.
The main memory of program TSIM consists of a big vector containing the names and values of all defined variables. The contents of the memory is updated by the input data commands in the left box, and by the integrator when stepping forward in time in the right box.
The time integration part of program TSIM integrates all variables defined by the user as integrated variables. An integrated variable can only be set by the integrator and cannot be overwritten by any other command. The following input data commands creates integrated variables: mass m_rigid_1, mass m_rigid_6, mass m_rigid_36b, mass m_flex_1, mass massless2, func integ, func hpass*, func lpass*, coupl kc, coupl kckc, coupl kfrkc and coupl k_air3.
Program TSIM has many integration methods which the user can choose between. The different methods are of different orders, why tstep may not be a constant value. The different integration methods are defined in the CALC-command tsim_param. All integrated variables in the main memory is updated at the end of the execution of the integrator.