% -> Mesh data generieren
nu = 20;    nv = 50;
umin = -10;   umax = 10;    
vmin = -10;   vmax = 10;

u = linspace( umin,umax,nu);
v = linspace( vmin,vmax,nv);

[ U,V ] = meshgrid( u,v );

% -> Derivative Daten erzeugen

UP = alpha.*U + beta.*U.*V;
VP = -gamma.*V + delta.*U.*V;


% -> Plot
quiver ( U, V, UP, VP, 3 );
axis ( [ umin umax vmin vmax ] );
title ( 'Lotka-Volterra \alpha = 0.01, \beta = 0.02, \gamma = 0.1 \delta = 0.002' );
xlabel ( 'u' );	ylabel ( 'v' );
set ( gca, 'DataAspectRatio', [ 1 1 1 ] );