User`s guide

2 Simulink and the DSP Blockset
2-14
duration of the simulation. Simulink additionally precomputes the outputs
of all downstream blocks driven exclusively by constant blocks.
In the example below, the input to the top port (
U) of the Matrix Multiply
block is computed only once, at the start of the simulation.
This eliminates the computational overhead of continuously reevaluating
these constant branches, which in turn results in faster simulation, and
smaller and more efficient generated code.
Note, however, that when
'InvariantConstants' is set to 'on', changes
that you make to parameters in a constant block while the simulation is
running are not registered by Simulink, and do not affect the simulation. If
you would like to adjust the model constants while the simulation is running,
you can turn off
'InvariantConstants' by deselecting the Inline
Parameters
check box in the Advanced panel of the Simulation
Parameters
dialog box.
•
'RTWOptions' sets loop-rolling threshold to 2
By default, the Real-Time Workshop “unrolls” a given loop into inline code
when the number of loop iterations is less than five. This avoids the overhead
precompute
d