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Linear programming is the study of optimizing a linear function over a set of linear inequalities. The Simplex Method, Ellipsoid Method and Interior Point Method are popular algorithms to solve linear programs.

1 vote
Accepted

Large scale least squares of non symmetric and non square problems

A widely used iterative method for large scale linear least squares problems that allows for regularization if you want/need it is the LSQR algorithm of Paige and Saunders. See http://www.stanford.ed …
Brian Borchers's user avatar
2 votes

Sensitivity analysis in conic optimization

In general, your problem can become infeasible under arbitrarily small perturbations $\Delta b$. For example, consider the problem $\min X_{11}+X_{22}$ subject to $X_{11}=0$ $X_{22}=0$ $X \suc …
Brian Borchers's user avatar
1 vote

generalization from linear programming solution

You should look into the topic of "parameteric linear programming". In certain situations where the problem data vary linearly with parameters, you can derive formulas for the optimal solution and op …
Brian Borchers's user avatar
6 votes

Why are optimization problems often called "programs"?

When the term "linear programming" first came into use, computers were still very rare beasts, and the term "computer programming" wasn't that widely used. Here "programming" meant planning. As rese …
Brian Borchers's user avatar
1 vote
Accepted

Rewrite optimization objective

Here's a solution for the specific case where $f(x)=\| x \|_{1}$ and $g(x)=\| y-Ax \|_{2}$. The same appraoch applies to $g(x)=\| A^{T}(y-Ax) \|_{\infty}$. There are two cases. If $g(0) \leq s$, …
Brian Borchers's user avatar
1 vote

Rewrite optimization objective

You need to start by by being explicit about the "equivalence" between the problems. Do you mean that "For every $s$, there is a $t$ such that if $x^{ * }$ is an optimal solution to the first problem …
Brian Borchers's user avatar
1 vote

positive semidefiniteness: a psd matrix substracted by another rank 1 psd matrix

This is easy to formulate as a semidefinite programming problem. First, let $X=xx^{T}$. The semidefiniteness constraint becomes $A-\lambda X \succeq 0$ Next, use a standard technique to handle t …
Brian Borchers's user avatar
1 vote
Accepted

What does "Vertex Solution" mean?

In the context of linear programming, and assuming that you're using the simplex method to solve your LP's rather than an interior point method, it's most likely that the author means "basic feasible …
Brian Borchers's user avatar
1 vote
Accepted

Nonstandard Hessian approximations in Gauss-Newton

You could certainly try this, but you'd have to do a lot of careful analysis to derive any convergence results. Among other things to consider: Your objective E(x) is more likely to have local mini …
Brian Borchers's user avatar
2 votes

Levenberg-Marquadt near the minima for non-zero-residual problems

The technique of multiplying the diagonal by $(1+\lambda)$ fails when you've got a 0 on the diagonal of $J^{T}J$. Having a zero on the diagonal of $J^{T}J$ can happen when you're far away from the op …
Brian Borchers's user avatar
3 votes
Accepted

Cascading minimization problems

You can solve the first LP, obtain the optimal value, and then add a constraint that the first objective has that optimal value. Then you can add your second set of constraints to the original set of …
Brian Borchers's user avatar
3 votes
Accepted

linear programming with OR restrictions

Your additional constraints make the feasible region for your problem nonconvex, and thus it cannot be represented as a linear programming problem. If you can obtain an upper bound $M_{i}$ on the max …
Brian Borchers's user avatar
1 vote

SDP Algorithms/ maximally complementary solutions

The standard approach is to embed the original SDP in a self dual formulation that has strictly feasible primal/dual solutions, solve the self dual formulation and then reach conclusions about the ori …
Brian Borchers's user avatar
1 vote

Efficient Algorithm For Projection Onto A Convex Set

You haven't told us anything about the size of your problem instances. How many terms are there in the sum of norms? What is $n$? Your problem is an example of a "sum of norms" optimization probl …
Brian Borchers's user avatar
1 vote

Continuity of Lexicographic Minimum Solution of a parametrized LP problem

You've chosen a somewhat limited form of "parametric LP" here. It's more common to allow $F$ to vary as $F=F_{0}+tF_{1}$. For that more general variety of parametric LP, the conjecture is false- it' …
Brian Borchers's user avatar

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