Select the diagnostic action to take if Simulink® software detects an algebraic loop while compiling the model.
When the Simulink software detects an algebraic loop, the software tries to solve the algebraic loop. If the software cannot solve the algebraic loop, it reports an error and the simulation terminates.
When Simulink software detects an algebraic loop, it displays a warning and tries to solve the algebraic loop. If the software cannot solve the algebraic loop, it reports an error and the simulation terminates.
When Simulink software detects an algebraic loop, it terminates the simulation, displays an error message, and highlights the portion of the block diagram that comprises the loop.
An algebraic loop generally occurs when an input port with direct feedthrough is driven by the output of the same block, either directly, or by a feedback path through other blocks with direct feedthrough. An example of an algebraic loop is this simple scalar loop.
When a model contains an algebraic loop, Simulink software calls a loop-solving routine at each time step. The loop solver performs iterations to determine the solution to the problem (if it can). As a result, models with algebraic loops run slower than models without them.
error option to highlight algebraic
loops when you simulate a model. This causes Simulink software to display an error dialog (the Diagnostic Viewer)
and recolor portions of the diagram that represent the first algebraic loop
that it detects. Simulink software uses red to color the blocks and lines that
constitute the loop. Closing the error dialog restores the diagram to its
See Algebraic Loop Concepts for more information.