Notes in TTK4135

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Removal Requested 04/22/2024 Equation of a circle in the complex plane
Removal Requested 04/22/2024 Den deriverte til en funksjon 
Published 04/23/2024 Convex programming is used to describe a special case of the general constrained optimization problem in whichthe {{c1::objective function}} is convex…
Published 04/23/2024 The function \(f\) is a convex function if its domain \(S\) is a {{c1::convex set}} and if for any two points \(x\) and&…
Published 04/23/2024 Standardized formulation for optimization problems
Published 04/23/2024 When the objective function and all the constraints are linear functions of \(x\), the problem is a {{c1::linear programming problem}}. 
Published 04/23/2024 For {{c1::convex programming}} problems (as well as {{c1::linear programming}} problems), {{c2::local}} solutions are also {{c2::global}} solutions.&n…
Published 04/23/2024 A point \(x^*\) is a global minimizer if {{c1::\(f(x^*) \leq f(x)\) for all \(x\)}}.
Published 04/23/2024 Local minimizer
Published 04/23/2024 If \(f\) is {{c1::twice continuously differentiable}}, we may be able to tell that \(x^*\) is a local minimizer (and possibly a st…
Published 04/23/2024 Positive definite matrix 
Published 04/23/2024 Positive semidefinite matrix 
Published 04/23/2024 Degenerate basis
Published 04/23/2024 A linear program is degenerate if it has at least one {{c1::degenerate basis}}. 
Published 04/23/2024 The two fundamental strategies for moving from the current point \(x_k\) to a new iterate \(x_{k+1}\) in an optimization algorithm
Published 04/23/2024 In the trust region strategy, we find the candidate step \(p\) by approximately solving the following subproblem
Published 04/23/2024 When using trust region: If the candidate solution does not produce a sufficient decrease in the objective function, we conclude that the trust region…
Published 04/23/2024 Line search starts by fixing the {{c1::direction \(p_k\)}} and then identifying an appropriate distance - the {{c1::step length \(\alph…
Published 04/23/2024 Steepest descent direction formula 
Published 04/23/2024 Newton direction formula 
Published 04/23/2024 The main drawback of the Newton direction is the need for the {{c1::Hessian \(\nabla^2 f(x)\)}}.
Published 04/23/2024 Quasi-Newton search directions differ from Newton's method in that they do not require {{c1::computation of the Hessian}}, and yet they converge at a …
Published 04/23/2024 Definition of an active set
Published 04/23/2024 KKT condition of stationarity
Published 04/23/2024 KKT conditions of primal feasibility 
Published 04/23/2024 KKT condition of dual feasibility 
Published 04/23/2024 What is the LP trick for handling absolute values in an objective function, and how does it ensure the optimality of a solution?
Published 04/23/2024 What are principal leading minors in a matrix, and how are they determined?
Published 04/23/2024 What is Sylvester's Criterion, and how does it determine the positive definiteness of a symmetric matrix?
Published 04/23/2024 1-norm (sum-norm) for vectors
Published 04/23/2024 2-norm (Euclidean norm) for vectors
Published 04/23/2024 \(\infty\)-norm (max norm) for vectors
Published 04/23/2024 LICQ implies the uniqueness of {{c1::Lagrange multipliers}}. 
Published 04/23/2024 The Lagrangian multipliers are the {{c1::"hidden cost"}}/{{c1::"shadow prices"}} of constraints.
Published 04/23/2024 For a well-conditioned matrix, {{c1::small perturbations}} give {{c1::small changes}} in solution.
Published 04/24/2024 Condition number of a matrix (when solving \(Ax=b\))
Published 04/23/2024 A quadratic programming problem is a convex problem if {{c1::\(P \geq 0\)}}. 
Published 04/24/2024 Standardized formulation for quadratic programming problems 
Published 04/23/2024 There are two sources for no solution for linear programming problems
Published 04/23/2024 The three possible cases for solutions for linear programming problems
Published 04/23/2024 The dual LP problem
Published 04/23/2024 Strong duality
Published 04/23/2024 What is the LQG System matrix?
Published 04/23/2024 What are the Wolfe conditions for step size?
Published 04/23/2024 What is the "easiest" nonlinear programming problem? 
Published 04/23/2024 Under which conditions is a QP-problem convex?
Published 04/23/2024 A merit function \(\phi(x; \micro) \)is exact if {{c1::there is a positive scalar \(\micro^*\) such that for any \(\micro > \mi…
Published 04/23/2024 Definition of a feasible set \(\Omega\)
Published 04/23/2024 Formula for the Lagrangian
Published 04/23/2024 When there is an equality constraint, the feasible direction is {{c1::perpendicular to the gradient of the equality constraint}}. 
Published 04/24/2024 Given a feasible point \(x\) and the active constraint set \(\mathcal{A}(x)\), the set of linearized feasible directions \(\mathca…
Published 04/26/2024 When the problem is {{c1::convex}}, the KKT conditions are {{c2::necessary}} and {{c2::sufficient}} for a solution. 
Published 04/26/2024 Definition of the Hessian
Published 04/26/2024 KKT complementary condition
Published 04/26/2024 A possible solution is a point where there are no directions that are both {{c1::feasible}} and {{c1::descent}} directions.
Published 04/26/2024 What is a tangent cone? 
Published 04/26/2024 {{c2::Constraint qualifications}} are needed to rule out special cases where optimal solutions do not {{c1::fulfill the KKT conditions}}. 
Published 04/26/2024 For a {{c1::convex}} constrained optimization problem where {{c1::Slater's condition}} is fulfilled, the KKT conditions are {{c2::necessary}} and {{c2…
Published 04/26/2024 {{c2::LICQ}} implies {{c1::Slater's condition}}. 
Published 05/01/2024 Second-order sufficient conditionsSuppose that \(x^*\) is a local solution and that the LICQ condition is satisfied. Let \(\lambda^*\)&…
Published 04/28/2024 A matrix \(A \in \mathbb{R}^{m \times n}\) is a mapping: {{c1:: \(x \in \mathbb{R}^n \) to \(y \in \mathbb{R}^m\)}}
Published 04/28/2024 To use the {{c1::matrix inverse}} for solving linear equation systems is inefficient and numerically unstable. 
Published 04/28/2024 Standard form LP 
Published 04/28/2024 Lagrangian for a linear programming problem 
Published 04/28/2024 The Simplex method generates iterates that are BFP, and converge to a solution if {{c1::there are BFPs}}, and{{c1::one of them is a solution (Bas…
Published 04/28/2024 Fundamental theorem of linear programming
Published 04/28/2024 If an LP is {{c1::bounded}} and {{c1::non-degenerate}}, the Simplex method terminates at a {{c2::BOP}}. 
Published 04/28/2024 In {{c1::active set methods}}, one maintains an estimate of the set of {{c2::inequality constraints}} that are {{c2::active at the solution}}. 
Published 05/01/2024 Strong duality implies the following relationship between primal and dual
Published 05/02/2024 Will a linear MPC controller always be stable?
Published 05/02/2024 Discrete State Space Equations for linear system with kalman filter feedback
Published 05/02/2024 LTI system with disturbance model
Published 05/02/2024 Equations for linear state estimator with constant disturbance
Published 05/05/2024 Active set method for QPs (simplified)
Published 05/06/2024 If we know which {{c2::inequalities}} are active at the solution, {{c1::QP can be solved as EQP}}.
Published 05/09/2024 Nominal stability
Published 05/09/2024 Robust stability
Published 05/09/2024 Rule of thumb for achieving nominal stability for MPC 
Published 05/09/2024 How to ensure that there always is a solution to the MPC open-loop optimization problem? 
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