documentclass{article}
usepackage{pgfplots}
begin{document}
begin{tikzpicture}
  begin{axis}[domain=-1:1,y domain=-1:1]
    addplot3[surf] {x*y*exp(x+2*y-9*x^2-9*y^2)};
  end{axis}
end{tikzpicture}
end{document}