Programming scicos blocks
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use_flag - Use of flag in Scicos computational functions

Contents

• use_flag - Use of flag in Scicos computational functions
  • Module
  • Description
  • Authors

Module

• Scicos

Description

During the simulation, the compuational functions will be called with a given flag that corresponds to the task to be realized and with the event number by which it has been activated.

• Flag 4: Initialization This is done only once in the initialization phase for all blocks. Input event numbers are not used in that case. Outputs and states can be initialized. Some blocks use also this flag to open files, to do allocation and initialization of the field block->work or initialize graphic windows.

• Flag 6: Initialization, fixed-point computation Flag 6 is used to set constraints that must be satisfied at the initial time. Scicos uses a fixed point computation scheme to force the constraints so the blocks are called more than once with flag 6 at time 0. This is a special initialization technique for example to find the steady state of a system before running the simulation. Input event numbers are not used in this case.

• Flag 1: Output computation The output computation can be performed many times in one time step of the simulation in particular when the diagram contains blocks that use both discrete and continuous states and zero crossing surfaces. In the current version of Scicos all blocks are called with flag = 1 at least once in every simulation time step, even if they don't have any outputs.

• Flag 2: Discrete state computation If blocks use states, this flag is when the state registers block->x, block->z, block->oz, block->work must be set during discrete activation (with block->nevptr$\geq$0) but also to compute block->x in the case of activation due to an internal zero crossing, in which case the input event number block->nevptr will be -1.

• Flag 0: Continuous state derivative computation This flag is used when the derivative block->xd or residual block->res of the continuous state needs to be set. Only blocks that use continuous state are called with flag=0.

• Flag 3: Output event computation Output event computation is done for blocks with output event register during discrete activation but also zero crossing activation. Note that in this latter case, the input event number block->nevptr will be -1.

• Flag 9: Modes and zero crossing computation Flag 9 is used to evaluate the function of zero crossings block->g and to set the modes, block->mode.

• Flag 5: Ending All blocks are called with flag = 5 before the end of the simulation or when the simulator aborts the simulation in case an error occurs during the simulation. Input event numbers are not used in that case.

• Flag 7: Properties of the continuous state variables Set the properties of the continuous state variables. Used for the description of DAE system (also internally used and generated by Scicos/Modelica implementation).

• Flag 10: Jacobian computation Computation of Jacobian matrix of the system (internally used and generated by Scicos/Modelica implementation).

Authors

Alan Layec INRIA