# set_alg¶

Class method.

do_mpc.model.Model.set_alg(self, expr_name, expr)

Introduce new algebraic equation to model.

For the continous time model, the expression must be formulated as

$0 = g(x(t),u(t),z(t),p(t),p_{\text{tv}}(t))$

or for a discrete model:

$0 = g(x_k,u_k,z_k,p_k,p_{\text{tv},k})$

Note

For the introduced algebraic variables $$z \in \mathbb{R}^{n_z}$$ it is required to introduce exactly $$n_z$$ algebraic equations. Otherwise setup() will throw an error message.

Parameters: expr_name (string) – Name of the introduced expression expr (CasADi SX or MX) – CasADi SX or MX function depending on _x, _u, _z, _tvp, _p.