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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Variable as subscript in Linear Programming

I have to maximize this function $max \sum_{i=0}^{n}x_{i}$ , $\bar{x}\in \mathbb{Z}, \bar{x}\geq 0$ is to possible to define this as a constraint ? $\sum_{t=0}^{T_{i}}M_{i,x_{i+t}}= T_{i}$ (I'm using a variable as subscript,M is a matrix of…
Koinos
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Removing variable from LP problem?

max $4x_1 + 3x_2 - 2x_3$ Subject to $x_1 + x_2 + 2x_3 \le 3$ $x_1 + 2x_2 + x_3 \le 6$ $ x_1 \le2$ $x_1, x_2, x_3 \ge 0$ I was told to remove one of the variables(variable fixing) by looking at the coefficients in the object…
Nina
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Why is the constraint $x_1 \geq 3$?

Assignment in book: Farmer Jones must determine how many acres of corn and wheat to plant this year. An acre of wheat yields 25 bushels of wheat and requires 10 hours of labor per week. An acre of corn yields 10 bushels of corn and requires 4 hours…
Hikato
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Unit vectors starting with $4/5$.

Find a unit vector in $\mathbb{R}^3$ that has first component 4/5. Can we describe all such vectors?
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How to represent in Linear Programming (equations)?

Suppose $i$ varies from $0$ to $4$. $A_i$, $S_i$, $E_i$ are binary variables. Now, if $S_1=1$ and $E_3=1$, then how to make $A_1=A_2=A_3=1$ and $A_0=A_4=0$ using linear equations?
Dr.PB
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Are these solutions to a LP problem feasible? basic?

Consider the following LP: \begin{align*} \max 8x_1 + 14x_2 + 12x_3 + 50x_4\\ \text{s. t. } x_1 + 2x_2 + 2x_3 + 16x_4 &\le 8\\ 2x_1 + 3x_2 + 4x_3 + 5x_4 &\le 15\\ 5x_1 + 6x_2 + 8x_3 + 10x_4 &\le 40\\ x_1, x_2, x_3, x_4 &\ge 0 \end{align*} a) Is…
woaini
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LINEAR ALGEBRA how to find number of basic solutions

how can i find the total number of basic solutions to a linear programming problem MAX Z= 2X-4Y Subject to x+2y<3 3x+4y<5 x,y>0 How can we find total number of basic solutions.
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Does deleting a non-binding constraint change the optimal solution?

Q: Does deleting a non-binding constraint change optimal solution? If yes, give an example. If no, Prove it. My try so far: I read some articles. Some of them mentioned something called shadow price. But, i don't want that because i don't know the…
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How to create a trend line from several x values in LibreOffice?

Given a set of points, a trend line is a function $f(x)$ that is defined as $f(x) = a x + b$ Creating a trend line means to find the values of the constants $a$ and $b$. Given some data, A is the $x$ value, B is $y$: A B --- ----- …
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Knapsack problem

Knapsack problem we can solve several methods: dynamic programming branch and bound greedy method genetic algorithm Brute force Heuristic by the value / size Which of these methods gives accurate results? or all methods give only approximate…
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How can I derive the following Linear Programming

How can we derive the dual problem? max$_{x} v^{T} x$ subject to $w^{T} x \le W, 0 \le x_i \le 1 ( i=1,...,n )$ where $ v \in \Bbb {R}^{n}, w_i \in \Bbb {R}^{n} $ and $ W \in \Bbb {R} $
MOP
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Linear Programming Question regarding shipping costs with books

A publisher has orders for 600 copies of a certain text from San Franciso and 400 copies from Sacramento. The company has 700 copies in a warehouse in Novato, and 800 copies in a warehouse in Lodi. It costs 5 dollars to ship a text from Novato to…
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Linear programming solve minimization as maximization

Given the following problem: $$max \ x_1 + x_2\\ s.t. \ x_1 \ge 0\\ x_2 \ge 0 \\ x_2 - x_1 \le 1 \\ x_1 + 6x_2 \le 15 \\ 4x_1 - x_2 \le 10$$ The result is 5 as shown here: https://i.stack.imgur.com/sLqpd.jpg Why does the following hold? $$max \…
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Linear Programming query

Rewrite: If $x_1=1$ then $x_2+x_3+x_4+x_5=0$ in linear programming if variables $x_1,x_2,x_3,x_4,x_5$ are binary? Edit:Sorry the sum of $x_2,x_3,x_4$ and $x_5$ should equal $0$. I tried re-writing it as if the variables are non-binary am not sure…
johndoe
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Linear Programming: Minimize deviation and evenly maximize decisive variable

I came across linear programming while trying to find a solution to a problem. I didn't use LP before so pardon if it is naive question. I hope this forum can help. There are n tasks (x1, x2 .., xn) with current assigned values (r1, r2 .. rn) and…
R. V.
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