# Difference between revisions of "ApCoCoA-1:LinBox.Solve"

(Short description update.) |
(Added parameter and return value list.) |
||

Line 12: | Line 12: | ||

The return value will be a solution vector of the linear equation system or an empty matrix if no solution has been found. | The return value will be a solution vector of the linear equation system or an empty matrix if no solution has been found. | ||

− | + | <itemize> | |

+ | <item>@param <em>M</em> A matrix with components either of type INT, ZMOD or RAT.</item> | ||

+ | <item>@param <em>B</em> A matrix with components either of type INT, ZMOD or RAT.</item> | ||

+ | <item>@param <em>METHOD</em> A string specifying the solution method to use. Available methods are "Wiedemann", "BlasElim". Please see detailed description, too.</item> | ||

+ | <item>@return A matrix X representing a solution vector of the linear equation system M*X = B if a solution exists or the empty matrix otherwise.</item> | ||

+ | </itemize> | ||

<example> | <example> | ||

Use Z/(19)[x]; | Use Z/(19)[x]; |

## Revision as of 17:16, 22 April 2009

## LinBox.Solve

Solve a linear equation system.

### Syntax

LinBox.Solve(M:MAT, B:MAT):MAT LinBox.Solve(M:MAT, B:MAT, METHOD:STRING):MAT

### Description

**Please note:** The function(s) explained on this page is/are using the **ApCoCoAServer**. You will have to start the ApCoCoAServer in order to use

it/them. Please also note that you need an ApCoCoAServer with enabled LinBox support.

Let `M` and `B` be matrices defined over the ring of integers, a finite field or the field of rationals. This function tries to solve the linear equation system `M*X = B` by using the ApCoCoAServer supported by the LinBox library. If your base ring is the ring of integers or a finite field, you can pass `Wiedemann` as `METHOD` to let the ApCoCoAServer compute the solution by using the LinBox Wiedemann implementation. If you pass `BlasElim` instead in this case, the solution will be computed by using the LinBox BLAS elimination implementation. If you omit the parameter `METHOD`, `BlasElim` will be used as default value where applicable. Please note that the parameter `METHOD` will be ignored if your base ring is the field of rationals, i.e. in this case it is always the LinBox rational solver implementation that will be used for computing a solution.

The return value will be a solution vector of the linear equation system or an empty matrix if no solution has been found.

@param

*M*A matrix with components either of type INT, ZMOD or RAT.@param

*B*A matrix with components either of type INT, ZMOD or RAT.@param

*METHOD*A string specifying the solution method to use. Available methods are "Wiedemann", "BlasElim". Please see detailed description, too.@return A matrix X representing a solution vector of the linear equation system M*X = B if a solution exists or the empty matrix otherwise.

#### Example

Use Z/(19)[x]; M := BringIn(Mat([[1,3,4], [0,2,1]])); B := BringIn(Mat([[1], [2]])); LinBox.Solve(M, B); ------------------------------- Mat([ [-2 % 19], [1 % 19], [0 % 19] ]) ------------------------------- Use Q[x]; M := Mat([ [1,3,4], [0,2,1], [1,3,4] ]); B := Mat([ [1], [2], [0] ]); LinBox.Solve(M, B); ------------------------------- Mat([ [ ] ]) -------------------------------