Template Class ConstraintModelResidualTpl

Defined in File residual.hpp

Inheritance Relationships

Base Type

public crocoddyl::ConstraintModelAbstractTpl< _Scalar > (Template Class ConstraintModelAbstractTpl)

Class Documentation

template<typename _Scalar> class ConstraintModelResidualTpl : public crocoddyl::ConstraintModelAbstractTpl<_Scalar>

Residual-based constraint.

This constraint function uses a residual model to define equality / inequality constraint as

\[ \mathbf{\underline{r}} \leq \mathbf{r}(\mathbf{x}, \mathbf{u}) \leq \mathbf{\bar{r}} \]

where \(\mathbf{r}(\cdot)\) describes the residual function, and \(\mathbf{\underline{r}}\), \(\mathbf{\bar{r}}\) are the lower and upper bounds, respectively. We can define element-wise equality constraints by defining the same value for both: lower and upper values. Additionally, if we do not define the bounds, then it is assumed that \(\mathbf{\underline{r}}=\mathbf{\bar{r}}=\mathbf{0}\).

The main computations are carring out in calc and calcDiff routines. calc computes the constraint residual and calcDiff computes the Jacobians of the constraint function. Concretely speaking, calcDiff builds a linear approximation of the constraint function with the form: \(\mathbf{g_x}\in\mathbb{R}^{ng\times ndx}\), \(\mathbf{g_u}\in\mathbb{R}^{ng\times nu}\), \(\mathbf{h_x}\in\mathbb{R}^{nh\times ndx}\) \(\mathbf{h_u}\in\mathbb{R}^{nh\times nu}\). Additionally, it is important to note that calcDiff() computes the derivatives using the latest stored values by calc(). Thus, we need to run first calc().