CGAL 5.5 - CGAL and Solvers
LinearProgramTraits Concept Reference

## Definition

A concept that describes the set of methods used to define and solve a linear programming (lp) problem of the general form:

\begin{eqnarray*} & \mbox{minimize} & \mathbf{q}^{T}\mathbf{x} + r \\ & \mbox{subject to} & \mathbf{l} \leq A\mathbf{x} \leq \mathbf{u} \end{eqnarray*}

in $$n$$ real variables $$\mathbf{x} = (x_0, \ldots, x_{n-1})$$ and $$m$$ constraints.

Here,

• $$\mathbf{q}$$ is an $$n$$-dimensional vector (the linear objective function),
• $$r$$ is a constant,
• $$A$$ is an $$m\times n$$ matrix (the constraint matrix),
• $$\mathbf{l}$$ is an $$m$$-dimensional vector of lower constraint bounds, where $$l_i \in \mathbb{R} \cup \{-\infty\}$$ for all $$i$$,
• $$\mathbf{u}$$ is an $$m$$-dimensional vector of upper constraint bounds, where $$u_i \in \mathbb{R} \cup \{+\infty\}$$ for all $$i$$.

## Memory

void resize (const std::size_t n, const std::size_t m)
Allocates memory for n variables and m constraints in lp.

## Initialization

void set_q (const std::size_t i, const FT value)
Sets the entry qi of lp to value.

void set_r (const FT value)
Sets the entry r of lp to value.

void set_A (const std::size_t i, const std::size_t j, const FT value)
Sets the entry Aij in the row i and column j of the constraint matrix A of lp to value.

void set_l (const std::size_t i, const FT value)
Sets the entry li of lp to value.

void set_u (const std::size_t i, const FT value)
Sets the entry ui of lp to value.

## Solution

template<typename OutIterator >
bool solve (OutIterator solution)
solves the linear program. More...

## ◆ solve()

template<typename OutIterator >
 bool LinearProgramTraits::solve ( OutIterator solution )

solves the linear program.

Number of values in solution equals to the number n of values in the vector x.

Template Parameters
 OutIterator a model of OutputIterator that accepts values of type FieldNumberType
Parameters
 solution an output iterator with the solution
Returns
a status of the computation success == true