[pstricks] Re: Hyperbolas

[Jacques L'helgoualc'h]

Herbert Voss a écrit, lundi 7 février 2005, à 08:09 :
[...]
> \def\psthyperbola at ii#1#2#3#4{% a b -1/+1  -1/+1
>   \parametricplot{0}{6.28}{%
>     /a #1 def /b #2 def
>     a t COSH mul #3 mul b t SINH mul #4 mul}
> }

I suggest rational parameters (quicker, and maybe a better plotpoints
repartition)

\def\psthyperbola at ii#1#2#3#4{% a b -1/+1  -1/+1
  \parametricplot{0}{.99}{%
    /a #1 def /b #2 def
    /d {1 t dup mul sub} bind def
    a t dup mul 1 add d div mul #3 mul
    b t 2 mul d div mul #4 mul}
}

-- 
Jacques L'helgoualc'h