No hope for Mathematica

There is no hope as such for Mathematica problem. I would have to reply solely on IDL and probable integration of which with Mathematica. I still have one more option open, to write iteration method inside Mathematica. One such fine example can be found here:
pi[n_, theta_] := 
Module[{p1,p2}, 
   p1=0; 
   p2=1; 
   Do[ 
     p1=p2*(2i-1)/(i-1) Cos[theta] -  i/(i-1) p1; 
     tmp=p2; 
     p2=p1; 
     p1=tmp,{i,2,n}] 
   p2 
]

But it doesn't make a sense to try too much with Mathematica, when IDL is working pretty good.