Questions tagged [linear-programming]

Questions on linear programming, the optimization of a linear function subject to linear constraints.

A linear programming problem may be defined as the problem of maximizing or minimizing a linear function subject to linear constraints. The constraints may be equalities or inequalities.

Linear programs are problems that can be expressed in canonical form as \begin{align}\max\quad&c^\top x\\\text{s.t.}\quad& Ax\le b\\\quad& x\ge 0\end{align} where $x$ represents the vector of variables (to be determined), $c$ and $b$ are vectors of (known) coefficients, $A$ is a (known) matrix of coefficients, and ${\displaystyle (\cdot )^{\top}}$ is the matrix transpose.

The expression to be maximized or minimized is called the objective function ($c^{\top}x$ in this case).

The inequalities $Ax \le b$ and $x \ge 0$ are the constraints which specify a convex polytope over which the objective function is to be optimized. The inequality $x \ge 0$ is called non-negativity constraints and are often found in linear programming problems. The other inequality $Ax \le b$ is called the main constraints.

Applications:

Linear programming can be applied to various fields of study. It is widely used in mathematics, and to a lesser extent in business, economics, and for some engineering problems. Industries that use linear programming models include transportation, energy, telecommunications, and manufacturing. It has proven useful in modeling diverse types of problems in planning, routing, scheduling, assignment, and design.

References:

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How to calculate the variance of linear prediction parameters?

I'm using linear prediction with singular value decomposition (LPSVD) to analyze signals that are damped sinusoids. If my understanding of the theory of linear prediction is correct (and it may not be) then LPSVD is actually doing a linear least…
DavidH
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What is the number of consignments that would be packed in the initial $113$ hours?

QUESTION: In a factory, $20$ workers start working on a project of packing consignments. They need exactly $5$ hours to pack one consignment. Every hour $4$ new workers join the existing workforce. It is mandatory to relieve a worker after $10$…
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Linear program to minimize distance between towers and citizen

I am trying to obtain the best coverage of towers around citizens, so they can walk as little as possible to reach a tower. Let the position of all citizens as $ \{ (a_k, b_k) \mid k \in [1, c] \} $ and the position of all towers as $ \{ (x_n, y_n)…
Likar
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Explanation of the maximization in LP formulated "minimax"

I am following Prof. Williams's description of the linear programming formulation [1] of the minimax problem: Minimize: $\left( \underset{i}{\rm Maximum} \sum\limits_j a_{ij} x_j \right)$ subject to: conventional linear…
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linear programming with non-integer constraints

Suppose we have a linear progamming of vertex packing for a hypergraph (V,E), with size $n = \sum_{e \in E} |e|$. We introduce a variable $x_v$ for each vertex $v \in V$. The integral version is stated as follows: $$\max \sum_{v \in V} x_v $$ $$s.t.…
Xiao
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Linear program solutions with three decision variables

Suppose we have a linear program which has exactly three non-negative decision variables x1, x2, x3 and exactly three functional constraints, each containing a single variable: xi ≤ 1, i ∈ {1, 2, 3}. How do we find the number of basic and feasible…
CalcBoy
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How to use Farkas' lemma to create a system that must have a solution, given $Ax=0,x\ge0, c\cdot x>0$ does not have one?

Suppose the system: $Ax=0,x \geq 0, $ and $c \cdot x > 0$ does not have a solution. How can I apply Farkas' lemma to create a system that must have a solution? I'm not so sure how to proceed, since the system doesn't resemble the typical system…
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Solving a linear system of equations with multiple solutions by minimizing the total error

Say you have the following system of equations: 100x + 200y + 200z = 250 95x + 180y + 190z = 220 85x + 210y + 210z = 240 with additional constraints on each variable given by: x >= .55 x <= .75 y >= .80 y <= .95 z >= .10 z <= .25 I have used the…
Jason
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Can we assume without loss of generality that $m \leq n$ in a linear programming theorem?

If I'm making a specific theorem about linear programming, is it acceptable to assume, without loss of generality, that either $m \geq n$, or, $n \geq m$? Specifically, I saw this in the book Combinatorial Optimization: Algorithms and Complexity by…
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find the optimal value of the cost function?

Use duality to find the optimal value of the cost function in the following linear programming problem: Max. $x + y + z$ such that $3x + 2y + 2z = 1,$ $x ≥ 0, y ≥ 0, z ≥ 0$ One of my friend said me that used Largangian and dual function but im not…
jasmine
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how to write down the dual of the linear programming problem?

Write down the dual of the linear programming problem: Max. : $2x + 3y$ such that $x + 2y = 3$ $2x + y ≥ 4$ $x + y ≤ 5$ $x ≥ 0 , y ≥ 0.$ My attempt : Min $ 3w_1 + 4w_2$ such that $w_1 + 2w_3 +w_3 \ge 2$ $2w_1 +w_2 +w_3 \ge 3$ $w_1 \ge 0 , w_2 \ge…
jasmine
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online visualizer for dual primal in 2D plane

Is there an online app that helps visualize the following: I can specify several lines in 2D plane which defines the inequalities and I will give a direction which specifies the objective. Thus this is a complete LP primal problem. And then the app…
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How to find the objective function of the dual problem

Consider the linear programming Problem: Maximize $z= 2x_1 +3x_2 +x_3$ such that $4x_1+3x_2 + x_3=6$ $x_1 + 2x_2 + 5x_3 \ge 4$ $x_1, x_2 , x_3 \ge 0$ Write down the objective function of the dual problem My attempt : From $4x_1+3x_2 +…
jasmine
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Linear optimization problem; why are $x_1$ and $x_2$ number of chairs and tables?

I am following a course on linear optimization; and unfortunately my brain is already stuck on the first toy example. The example is as follows: Your company produces Duplo chairs and tables. Profit per chair is 15, profit per table is 20 dollars.…
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How to convert $\min_x \max_i a_i^{\top}x$ to a standard linear program?

Here is an example of $\min \max $ that should be converted to a linear program. $$\min_{x \in \mathbb{R}^n} \,\,\,\max_{i = 1, \cdots, m} a_i^{\top}x \tag{1}$$ We know the standard primal linear program is defined as follows: $$ \min…
user494522