# sylv

Sylvester equation.

## Calling Sequence

    sylv(A,B,C,flag)

## Arguments

A,B,C

  three real matrices of appropriate dimensions.

flag

  character string (`'c'` or `'d'`)

## Description

`X= sylv(A,B,C,'c')` computes `X`, solution of the "continuous time" Sylvester equation

    A*X+X*B=C

`X=sylv(A,B,C,'d')` computes `X`, solution of the "discrete time" Sylvester equation

    A*X*B-X=C

## Examples

    A=rand(4,4);C=rand(4,3);B=rand(3,3);
    X = sylv(A,B,C,'c');
    norm(A*X+X*B-C)
    X=sylv(A,B,C,'d')
    norm(A*X*B-X-C)

## See Also

- lyap