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SolverDDP Class Reference

Differential Dynamic Programming (DDP) solver. More...

#include <crocoddyl/core/solvers/ddp.hpp>

Inheritance diagram for SolverDDP:
Collaboration diagram for SolverDDP:

Public Member Functions

 SolverDDP (boost::shared_ptr< ShootingProblem > problem)
 Initialize the DDP solver. More...
 
virtual void allocateData ()
 Allocate all the internal data needed for the solver.
 
virtual void backwardPass ()
 Run the backward pass (Riccati sweep) More...
 
virtual double calcDiff ()
 Update the Jacobian, Hessian and feasibility of the optimal control problem. More...
 
virtual void computeDirection (const bool recalc=true)
 Compute the search direction \((\delta\mathbf{x}^k,\delta\mathbf{u}^k)\) for the current guess \((\mathbf{x}^k_s,\mathbf{u}^k_s)\). More...
 
virtual void computeGains (const std::size_t t)
 Compute the feedforward and feedback terms using a Cholesky decomposition. More...
 
void decreaseRegularization ()
 Decrease the state and control regularization values by a regfactor_ factor.
 
 DEPRECATED ("Use get_reg_incfactor() or get_reg_decfactor()", double get_regfactor() const ;) double get_reg_min() const
 Return the regularization factor used to decrease / increase it. More...
 
 DEPRECATED ("Use get_reg_max()", double get_regmax() const)
 
 DEPRECATED ("Use get_reg_min()", double get_regmin() const)
 
 DEPRECATED ("Use set_reg_incfactor() or set_reg_decfactor()", void set_regfactor(const double reg_factor);) void set_reg_min(const double regmin)
 Modify the regularization factor used to decrease / increase it. More...
 
 DEPRECATED ("Use set_reg_max()", void set_regmax(const double regmax))
 
 DEPRECATED ("Use set_reg_min()", void set_regmin(const double regmin))
 
virtual const Eigen::Vector2d & expectedImprovement ()
 Return the expected improvement \(dV_{exp}\) from a given current search direction \((\delta\mathbf{x}^k,\delta\mathbf{u}^k)\). More...
 
virtual void forwardPass (const double stepLength)
 Run the forward pass or rollout. More...
 
const std::vector< double > & get_alphas () const
 Return the set of step lengths using by the line-search procedure.
 
const std::vector< MatrixXdRowMajor > & get_K () const
 Return the feedback gains \(\mathbf{K}_{s}\).
 
const std::vector< Eigen::VectorXd > & get_k () const
 Return the feedforward gains \(\mathbf{k}_{s}\).
 
const std::vector< Eigen::VectorXd > & get_Qu () const
 Return the Jacobian of the Hamiltonian function \(\mathbf{Q}_{\mathbf{u}_s}\).
 
const std::vector< Eigen::MatrixXd > & get_Quu () const
 Return the Hessian of the Hamiltonian function \(\mathbf{Q}_{\mathbf{uu}_s}\).
 
const std::vector< Eigen::VectorXd > & get_Qx () const
 Return the Jacobian of the Hamiltonian function \(\mathbf{Q}_{\mathbf{x}_s}\).
 
const std::vector< Eigen::MatrixXd > & get_Qxu () const
 Return the Hessian of the Hamiltonian function \(\mathbf{Q}_{\mathbf{xu}_s}\).
 
const std::vector< Eigen::MatrixXd > & get_Qxx () const
 Return the Hessian of the Hamiltonian function \(\mathbf{Q}_{\mathbf{xx}_s}\).
 
double get_reg_decfactor () const
 Return the regularization factor used to decrease the damping value.
 
double get_reg_incfactor () const
 Return the regularization factor used to increase the damping value.
 
double get_reg_max () const
 Return the maximum regularization value.
 
double get_th_grad () const
 Return the tolerance of the expected gradient used for testing the step.
 
double get_th_stepdec () const
 Return the step-length threshold used to decrease regularization.
 
double get_th_stepinc () const
 Return the step-length threshold used to increase regularization.
 
const std::vector< Eigen::VectorXd > & get_Vx () const
 Return the Hessian of the Value function \(V_{\mathbf{x}_s}\).
 
const std::vector< Eigen::MatrixXd > & get_Vxx () const
 Return the Hessian of the Value function \(V_{\mathbf{xx}_s}\).
 
void increaseRegularization ()
 Increase the state and control regularization values by a regfactor_ factor.
 
virtual void resizeData ()
 Resizing the solver data. More...
 
void set_alphas (const std::vector< double > &alphas)
 Modify the set of step lengths using by the line-search procedure.
 
void set_reg_decfactor (const double reg_factor)
 Modify the regularization factor used to decrease the damping value.
 
void set_reg_incfactor (const double reg_factor)
 Modify the regularization factor used to increase the damping value.
 
void set_reg_max (const double regmax)
 Modify the maximum regularization value.
 
void set_th_grad (const double th_grad)
 Modify the tolerance of the expected gradient used for testing the step.
 
void set_th_stepdec (const double th_step)
 Modify the step-length threshold used to decrease regularization.
 
void set_th_stepinc (const double th_step)
 Modify the step-length threshold used to increase regularization.
 
virtual bool solve (const std::vector< Eigen::VectorXd > &init_xs=DEFAULT_VECTOR, const std::vector< Eigen::VectorXd > &init_us=DEFAULT_VECTOR, const std::size_t maxiter=100, const bool is_feasible=false, const double regInit=1e-9)
 Compute the optimal trajectory \(\mathbf{x}^*_s,\mathbf{u}^*_s\) as lists of \(T+1\) and \(T\) terms. More...
 
virtual double stoppingCriteria ()
 Return a positive value that quantifies the algorithm termination. More...
 
virtual double tryStep (const double steplength=1)
 Try a predefined step length \(\alpha\) and compute its cost improvement \(dV\). More...
 
- Public Member Functions inherited from SolverAbstract
EIGEN_MAKE_ALIGNED_OPERATOR_NEW SolverAbstract (boost::shared_ptr< ShootingProblem > problem)
 Initialize the solver. More...
 
double computeDynamicFeasibility ()
 Compute the dynamic feasibility \(\|\mathbf{f}_{\mathbf{s}}\|_{\infty,1}\) for the current guess \((\mathbf{x}^k,\mathbf{u}^k)\). More...
 
double get_cost () const
 Return the total cost.
 
const Eigen::Vector2d & get_d () const
 Return the LQ approximation of the expected improvement.
 
double get_dV () const
 Return the cost reduction \(dV\).
 
double get_dVexp () const
 Return the expected cost reduction \(dV_{exp}\).
 
double get_ffeas () const
 Return the feasibility of the dynamic constraints \(\|\mathbf{f}_{\mathbf{s}}\|_{\infty,1}\) of the current guess.
 
const std::vector< Eigen::VectorXd > & get_fs () const
 Return the gaps \(\mathbf{f}_{s}\).
 
bool get_inffeas () const
 Return the norm used for the computing the feasibility (true for \(\ell_\infty\), false for \(\ell_1\))
 
bool get_is_feasible () const
 Return the feasibility status of the \((\mathbf{x}_s,\mathbf{u}_s)\) trajectory.
 
std::size_t get_iter () const
 Return the number of iterations performed by the solver.
 
const boost::shared_ptr< ShootingProblem > & get_problem () const
 Return the shooting problem.
 
double get_steplength () const
 Return the step length \(\alpha\).
 
double get_stop () const
 Return the value computed by stoppingCriteria()
 
double get_th_acceptstep () const
 Return the threshold used for accepting a step.
 
double get_th_gaptol () const
 Return the threshold for accepting a gap as non-zero.
 
double get_th_stop () const
 Return the tolerance for stopping the algorithm.
 
double get_ureg () const
 Return the control regularization value.
 
const std::vector< Eigen::VectorXd > & get_us () const
 Return the control trajectory \(\mathbf{u}_s\).
 
double get_xreg () const
 Return the state regularization value.
 
const std::vector< Eigen::VectorXd > & get_xs () const
 Return the state trajectory \(\mathbf{x}_s\).
 
const std::vector< boost::shared_ptr< CallbackAbstract > > & getCallbacks () const
 Return the list of callback functions using for diagnostic.
 
void set_inffeas (const bool inffeas)
 Modify the current norm used for computed the feasibility.
 
void set_th_acceptstep (const double th_acceptstep)
 Modify the threshold used for accepting step.
 
void set_th_gaptol (const double th_gaptol)
 Modify the threshold for accepting a gap as non-zero.
 
void set_th_stop (const double th_stop)
 Modify the tolerance for stopping the algorithm.
 
void set_ureg (const double ureg)
 Modify the control regularization value.
 
void set_us (const std::vector< Eigen::VectorXd > &us)
 Modify the control trajectory \(\mathbf{u}_s\).
 
void set_xreg (const double xreg)
 Modify the state regularization value.
 
void set_xs (const std::vector< Eigen::VectorXd > &xs)
 Modify the state trajectory \(\mathbf{x}_s\).
 
void setCallbacks (const std::vector< boost::shared_ptr< CallbackAbstract > > &callbacks)
 Set a list of callback functions using for the solver diagnostic. More...
 
void setCandidate (const std::vector< Eigen::VectorXd > &xs_warm=DEFAULT_VECTOR, const std::vector< Eigen::VectorXd > &us_warm=DEFAULT_VECTOR, const bool is_feasible=false)
 Set the solver candidate trajectories \((\mathbf{x}_s,\mathbf{u}_s)\). More...
 

Public Attributes

EIGEN_MAKE_ALIGNED_OPERATOR_NEW typedef MathBaseTpl< double >::MatrixXsRowMajor MatrixXdRowMajor
 

Protected Attributes

std::vector< double > alphas_
 Set of step lengths using by the line-search procedure.
 
double cost_try_
 Total cost computed by line-search procedure.
 
std::vector< Eigen::VectorXd > dx_
 State error during the roll-out/forward-pass (size T)
 
Eigen::VectorXd fTVxx_p_
 Store the value of \(\mathbf{\bar{f}}^T\mathbf{V_{xx}}^{'}\).
 
std::vector< MatrixXdRowMajor > FuTVxx_p_
 Store the values of \(\mathbf{f_u}^T\mathbf{V_{xx}}^{'}\) per each running node.
 
MatrixXdRowMajor FxTVxx_p_
 Store the value of \(\mathbf{f_x}^T\mathbf{V_{xx}}^{'}\).
 
std::vector< MatrixXdRowMajor > K_
 Feedback gains \(\mathbf{K}\).
 
std::vector< Eigen::VectorXd > k_
 Feed-forward terms \(\mathbf{l}\).
 
std::vector< Eigen::VectorXd > Qu_
 Gradient of the Hamiltonian \(\mathbf{Q_u}\).
 
std::vector< Eigen::MatrixXd > Quu_
 Hessian of the Hamiltonian \(\mathbf{Q_{uu}}\).
 
std::vector< Eigen::LLT< Eigen::MatrixXd > > Quu_llt_
 Cholesky LLT solver.
 
std::vector< Eigen::VectorXd > Quuk_
 Store the values of.
 
std::vector< Eigen::VectorXd > Qx_
 Gradient of the Hamiltonian \(\mathbf{Q_x}\).
 
std::vector< Eigen::MatrixXd > Qxu_
 Hessian of the Hamiltonian \(\mathbf{Q_{xu}}\).
 
std::vector< Eigen::MatrixXd > Qxx_
 Hessian of the Hamiltonian \(\mathbf{Q_{xx}}\).
 
double reg_decfactor_
 Regularization factor used to decrease the damping value.
 
double reg_incfactor_
 Regularization factor used to increase the damping value.
 
double reg_max_
 Maximum allowed regularization value.
 
double reg_min_
 Minimum allowed regularization value.
 
double th_grad_
 Tolerance of the expected gradient used for testing the step.
 
double th_stepdec_
 Step-length threshold used to decrease regularization.
 
double th_stepinc_
 Step-length threshold used to increase regularization.
 
std::vector< Eigen::VectorXd > us_try_
 Control trajectory computed by line-search procedure.
 
std::vector< Eigen::VectorXd > Vx_
 Gradient of the Value function \(\mathbf{V_x}\).
 
std::vector< Eigen::MatrixXd > Vxx_
 Hessian of the Value function \(\mathbf{V_{xx}}\).
 
Eigen::MatrixXd Vxx_tmp_
 Temporary variable for ensuring symmetry of Vxx.
 
Eigen::VectorXd xnext_
 Next state \(\mathbf{x}^{'}\).
 
std::vector< Eigen::VectorXd > xs_try_
 State trajectory computed by line-search procedure.
 
- Protected Attributes inherited from SolverAbstract
std::vector< boost::shared_ptr< CallbackAbstract > > callbacks_
 Callback functions.
 
double cost_
 Total cost.
 
Eigen::Vector2d d_
 LQ approximation of the expected improvement.
 
double dV_
 Cost reduction obtained by tryStep()
 
double dVexp_
 Expected cost reduction.
 
double ffeas_
 Feasibility of the dynamic constraints.
 
std::vector< Eigen::VectorXd > fs_
 Gaps/defects between shooting nodes.
 
bool inffeas_
 
bool is_feasible_
 Label that indicates is the iteration is feasible.
 
std::size_t iter_
 Number of iteration performed by the solver.
 
boost::shared_ptr< ShootingProblemproblem_
 optimal control problem
 
double steplength_
 Current applied step-length.
 
double stop_
 Value computed by stoppingCriteria()
 
double th_acceptstep_
 Threshold used for accepting step.
 
double th_gaptol_
 Threshold limit to check non-zero gaps.
 
double th_stop_
 Tolerance for stopping the algorithm.
 
double tmp_feas_
 Temporal variables used for computed the feasibility.
 
double ureg_
 Current control regularization values.
 
std::vector< Eigen::VectorXd > us_
 Control trajectory.
 
bool was_feasible_
 Label that indicates in the previous iterate was feasible.
 
double xreg_
 Current state regularization value.
 
std::vector< Eigen::VectorXd > xs_
 State trajectory.
 

Detailed Description

Differential Dynamic Programming (DDP) solver.

The DDP solver computes an optimal trajectory and control commands by iterates running backwardPass() and forwardPass(). The backward-pass updates locally the quadratic approximation of the problem and computes descent direction. If the warm-start is feasible, then it computes the gaps \(\mathbf{f}_s\) and run a modified Riccati sweep:

\begin{eqnarray*} \mathbf{Q}_{\mathbf{x}_k} &=& \mathbf{l}_{\mathbf{x}_k} + \mathbf{f}^\top_{\mathbf{x}_k} (V_{\mathbf{x}_{k+1}} + V_{\mathbf{xx}_{k+1}}\mathbf{\bar{f}}_{k+1}),\\ \mathbf{Q}_{\mathbf{u}_k} &=& \mathbf{l}_{\mathbf{u}_k} + \mathbf{f}^\top_{\mathbf{u}_k} (V_{\mathbf{x}_{k+1}} + V_{\mathbf{xx}_{k+1}}\mathbf{\bar{f}}_{k+1}),\\ \mathbf{Q}_{\mathbf{xx}_k} &=& \mathbf{l}_{\mathbf{xx}_k} + \mathbf{f}^\top_{\mathbf{x}_k} V_{\mathbf{xx}_{k+1}} \mathbf{f}_{\mathbf{x}_k},\\ \mathbf{Q}_{\mathbf{xu}_k} &=& \mathbf{l}_{\mathbf{xu}_k} + \mathbf{f}^\top_{\mathbf{x}_k} V_{\mathbf{xx}_{k+1}} \mathbf{f}_{\mathbf{u}_k},\\ \mathbf{Q}_{\mathbf{uu}_k} &=& \mathbf{l}_{\mathbf{uu}_k} + \mathbf{f}^\top_{\mathbf{u}_k} V_{\mathbf{xx}_{k+1}} \mathbf{f}_{\mathbf{u}_k}. \end{eqnarray*}

Then, the forward-pass rollouts this new policy by integrating the system dynamics along a tuple of optimized control commands \(\mathbf{u}^*_s\), i.e.

\begin{eqnarray} \mathbf{\hat{x}}_0 &=& \mathbf{\tilde{x}}_0,\\ \mathbf{\hat{u}}_k &=& \mathbf{u}_k + \alpha\mathbf{k}_k + \mathbf{K}_k(\mathbf{\hat{x}}_k-\mathbf{x}_k),\\ \mathbf{\hat{x}}_{k+1} &=& \mathbf{f}_k(\mathbf{\hat{x}}_k,\mathbf{\hat{u}}_k). \end{eqnarray}

See also
SolverAbstract(), backwardPass() and forwardPass()

Definition at line 49 of file ddp.hpp.

Constructor & Destructor Documentation

◆ SolverDDP()

SolverDDP ( boost::shared_ptr< ShootingProblem problem)
explicit

Initialize the DDP solver.

Parameters
[in]problemshooting problem

Definition at line 16 of file ddp.cpp.

Member Function Documentation

◆ solve()

bool solve ( const std::vector< Eigen::VectorXd > &  init_xs = DEFAULT_VECTOR,
const std::vector< Eigen::VectorXd > &  init_us = DEFAULT_VECTOR,
const std::size_t  maxiter = 100,
const bool  is_feasible = false,
const double  reg_init = 1e-9 
)
virtual

Compute the optimal trajectory \(\mathbf{x}^*_s,\mathbf{u}^*_s\) as lists of \(T+1\) and \(T\) terms.

From an initial guess init_xs, init_us (feasible or not), iterate over computeDirection() and tryStep() until stoppingCriteria() is below threshold. It also describes the globalization strategy used during the numerical optimization.

Parameters
[in]init_xsinitial guess for state trajectory with \(T+1\) elements (default [])
[in]init_usinitial guess for control trajectory with \(T\) elements (default [])
[in]maxitermaximum allowed number of iterations (default 100)
[in]isFeasibletrue if the init_xs are obtained from integrating the init_us (rollout) (default false)
[in]regInitinitial guess for the regularization value. Very low values are typical used with very good guess points (init_xs, init_us)
Returns
A boolean that describes if convergence was reached.

Implements SolverAbstract.

Reimplemented in SolverFDDP.

Definition at line 42 of file ddp.cpp.

◆ computeDirection()

void computeDirection ( const bool  recalc = true)
virtual

Compute the search direction \((\delta\mathbf{x}^k,\delta\mathbf{u}^k)\) for the current guess \((\mathbf{x}^k_s,\mathbf{u}^k_s)\).

You must call setCandidate() first in order to define the current guess. A current guess defines a state and control trajectory \((\mathbf{x}^k_s,\mathbf{u}^k_s)\) of \(T+1\) and \(T\) elements, respectively.

Parameters
[in]recalctrue for recalculating the derivatives at current state and control
Returns
The search direction \((\delta\mathbf{x},\delta\mathbf{u})\) and the dual lambdas as lists of \(T+1\), \(T\) and \(T+1\) lengths, respectively

Implements SolverAbstract.

Definition at line 128 of file ddp.cpp.

◆ tryStep()

double tryStep ( const double  steplength = 1)
virtual

Try a predefined step length \(\alpha\) and compute its cost improvement \(dV\).

It uses the search direction found by computeDirection() to try a determined step length \(\alpha\). Therefore, it assumes that we have run computeDirection() first. Additionally, it returns the cost improvement \(dV\) along the predefined step length \(\alpha\).

Parameters
[in]steplengthapplied step length ( \(0\leq\alpha\leq1\))
Returns
the cost improvement

Implements SolverAbstract.

Definition at line 137 of file ddp.cpp.

◆ stoppingCriteria()

double stoppingCriteria ( )
virtual

Return a positive value that quantifies the algorithm termination.

These values typically represents the gradient norm which tell us that it's been reached the local minima. The stopping criteria strictly speaking depends on the search direction (calculated by computeDirection()) but it could also depend on the chosen step length, tested by tryStep().

Implements SolverAbstract.

Definition at line 144 of file ddp.cpp.

◆ expectedImprovement()

const Eigen::Vector2d & expectedImprovement ( )
virtual

Return the expected improvement \(dV_{exp}\) from a given current search direction \((\delta\mathbf{x}^k,\delta\mathbf{u}^k)\).

For computing the expected improvement, you need to compute the search direction first via computeDirection().

Implements SolverAbstract.

Reimplemented in SolverFDDP.

Definition at line 158 of file ddp.cpp.

◆ resizeData()

void resizeData ( )
virtual

Resizing the solver data.

If the shooting problem has changed after construction, then this function resizes all the data before starting resolve the problem.

Reimplemented from SolverAbstract.

Reimplemented in SolverBoxDDP, and SolverBoxFDDP.

Definition at line 172 of file ddp.cpp.

◆ calcDiff()

double calcDiff ( )
virtual

Update the Jacobian, Hessian and feasibility of the optimal control problem.

These derivatives are computed around the guess state and control trajectory. These trajectory can be set by using setCandidate().

Returns
the total cost around the guess trajectory

Definition at line 194 of file ddp.cpp.

◆ backwardPass()

void backwardPass ( )
virtual

Run the backward pass (Riccati sweep)

It assumes that the Jacobian and Hessians of the optimal control problem have been compute (i.e., calcDiff()). The backward pass handles infeasible guess through a modified Riccati sweep:

\begin{eqnarray*} \mathbf{Q}_{\mathbf{x}_k} &=& \mathbf{l}_{\mathbf{x}_k} + \mathbf{f}^\top_{\mathbf{x}_k} (V_{\mathbf{x}_{k+1}} + V_{\mathbf{xx}_{k+1}}\mathbf{\bar{f}}_{k+1}),\\ \mathbf{Q}_{\mathbf{u}_k} &=& \mathbf{l}_{\mathbf{u}_k} + \mathbf{f}^\top_{\mathbf{u}_k} (V_{\mathbf{x}_{k+1}} + V_{\mathbf{xx}_{k+1}}\mathbf{\bar{f}}_{k+1}),\\ \mathbf{Q}_{\mathbf{xx}_k} &=& \mathbf{l}_{\mathbf{xx}_k} + \mathbf{f}^\top_{\mathbf{x}_k} V_{\mathbf{xx}_{k+1}} \mathbf{f}_{\mathbf{x}_k},\\ \mathbf{Q}_{\mathbf{xu}_k} &=& \mathbf{l}_{\mathbf{xu}_k} + \mathbf{f}^\top_{\mathbf{x}_k} V_{\mathbf{xx}_{k+1}} \mathbf{f}_{\mathbf{u}_k},\\ \mathbf{Q}_{\mathbf{uu}_k} &=& \mathbf{l}_{\mathbf{uu}_k} + \mathbf{f}^\top_{\mathbf{u}_k} V_{\mathbf{xx}_{k+1}} \mathbf{f}_{\mathbf{u}_k}, \end{eqnarray*}

where \(\mathbf{l}_{\mathbf{x}_k}\), \(\mathbf{l}_{\mathbf{u}_k}\), \(\mathbf{f}_{\mathbf{x}_k}\) and \(\mathbf{f}_{\mathbf{u}_k}\) are the Jacobians of the cost function and dynamics, \(\mathbf{l}_{\mathbf{xx}_k}\), \(\mathbf{l}_{\mathbf{xu}_k}\) and \(\mathbf{l}_{\mathbf{uu}_k}\) are the Hessians of the cost function, \(V_{\mathbf{x}_{k+1}}\) and \(V_{\mathbf{xx}_{k+1}}\) defines the linear-quadratic approximation of the Value function, and \(\mathbf{\bar{f}}_{k+1}\) describes the gaps of the dynamics.

Definition at line 206 of file ddp.cpp.

◆ forwardPass()

void forwardPass ( const double  stepLength)
virtual

Run the forward pass or rollout.

It rollouts the action model given the computed policy (feedforward terns and feedback gains) by the backwardPass():

\begin{eqnarray} \mathbf{\hat{x}}_0 &=& \mathbf{\tilde{x}}_0,\\ \mathbf{\hat{u}}_k &=& \mathbf{u}_k + \alpha\mathbf{k}_k + \mathbf{K}_k(\mathbf{\hat{x}}_k-\mathbf{x}_k),\\ \mathbf{\hat{x}}_{k+1} &=& \mathbf{f}_k(\mathbf{\hat{x}}_k,\mathbf{\hat{u}}_k). \end{eqnarray}

We can define different step lengths \(\alpha\).

Parameters
stepLengthapplied step length ( \(0\leq\alpha\leq1\))

Reimplemented in SolverFDDP, SolverBoxDDP, and SolverBoxFDDP.

Definition at line 289 of file ddp.cpp.

◆ computeGains()

void computeGains ( const std::size_t  t)
virtual

Compute the feedforward and feedback terms using a Cholesky decomposition.

To compute the feedforward \(\mathbf{k}_k\) and feedback \(\mathbf{K}_k\) terms, we use a Cholesky decomposition to solve \(\mathbf{Q}_{\mathbf{uu}_k}^{-1}\) term:

\begin{eqnarray} \mathbf{k}_k &=& \mathbf{Q}_{\mathbf{uu}_k}^{-1}\mathbf{Q}_{\mathbf{u}},\\ \mathbf{K}_k &=& \mathbf{Q}_{\mathbf{uu}_k}^{-1}\mathbf{Q}_{\mathbf{ux}}. \end{eqnarray}

Note that if the Cholesky decomposition fails, then we re-start the backward pass and increase the state and control regularization values.

Reimplemented in SolverBoxDDP, and SolverBoxFDDP.

Definition at line 337 of file ddp.cpp.

◆ DEPRECATED() [1/2]

DEPRECATED ( "Use get_reg_incfactor() or get_reg_decfactor()"  ,
double get_regfactor() const ;   
) const

Return the regularization factor used to decrease / increase it.

Return the minimum regularization value

◆ DEPRECATED() [2/2]

DEPRECATED ( "Use set_reg_incfactor() or set_reg_decfactor()"  ,
void set_regfactor(const double reg_factor);   
) const

Modify the regularization factor used to decrease / increase it.

Modify the minimum regularization value


The documentation for this class was generated from the following files: