Constrain input signal to zero
The Algebraic Constraint block constrains the input signal f(z) to zero and outputs an algebraic state z. The block outputs the value that produces a zero at the input. The output must affect the input through a direct feedback path, that is, the feedback path contains only blocks with direct feedthrough. For example, you can specify algebraic equations for index 1 differential-algebraic systems (DAEs).
The Algebraic Constraint block uses a dogleg trust-region algorithm to solve algebraic loops , .
By default, the Initial guess parameter is zero. You can improve the efficiency of the algebraic-loop solver by providing an Initial guess for the algebraic state z that is close to the solution value.
z2 + z1 = 1 z2 - z1 = 1
The solution is z2 = 1, z1 = 0, as the Display blocks show.
Inherited from driving block