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The optimization problem in (3.16) is called a linear programming problem if<br />

the objective function <strong>and</strong> the constraint functions are linear, i.e.<br />

f i<br />

(x + y) = f i<br />

(x) + f i<br />

(y), i = 0,…,m. (3.18)<br />

The st<strong>and</strong>ard <strong>for</strong>m of a linear programming problem is <strong>for</strong>mulated as (3.19):<br />

minimize<br />

subject to<br />

c 1<br />

x 1<br />

+ c 2<br />

x 2<br />

++ c n<br />

x n<br />

a 11<br />

x 1<br />

+ a 12<br />

x 2<br />

++ a 1n<br />

x n<br />

b 1<br />

a 21<br />

x 1<br />

+ a 22<br />

x 2<br />

++ a 2n<br />

x n<br />

b 2<br />

<br />

(3.19)<br />

a m1<br />

x 1<br />

+ a m2<br />

x 2<br />

++ a mn<br />

x n<br />

b m<br />

x 1<br />

, x 2<br />

, x n<br />

0,<br />

or in matrix representation:<br />

minimize<br />

subject to<br />

c T x<br />

Ax b<br />

x 0,<br />

(3.20)<br />

where<br />

c = [ c 1<br />

c 2<br />

c n ] T<br />

x = [ x 1<br />

x 2<br />

x n ] T<br />

a 11<br />

a 12<br />

a 1n <br />

<br />

a 21<br />

a 22<br />

a<br />

<br />

2n<br />

A = <br />

<br />

<br />

<br />

<br />

a m1<br />

a m2<br />

a mn <br />

b = [ b 1<br />

b 2<br />

b n ] T .<br />

Linear programming problems have been well-studied, <strong>and</strong> various algorithms<br />

have been proposed with different levels of efficiency <strong>and</strong> complexity. The earliest <strong>and</strong><br />

yet still most popular solver <strong>for</strong> linear programming problems is the simplex algorithm<br />

43

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