function agm aa,g
    put abs(aa-g) into absdiff
    put (aa+g)/2 into aan
    put sqrt(aa*g) into gn
    repeat while abs(aan - gn) < absdiff
        put abs(aa-g) into absdiff
        put (aa+g)/2 into aan
        put sqrt(aa*g) into gn
        put aan into aa
        put gn into g
    end repeat
    return aa
end agm