Hello hugs-bugs-request, Sunday, March 23, 2003, 4:25:54 AM, you wrote: The following program: ------------------------------------ module StringSolver( fixedp, freep, connstr, solvestrings ) where -- start end length needed data ConnStr = ConnStr Int Int Double type V3 = (Double,Double,Double) data Point = FixedP V3 -- point that cannot move | FreeP V3 -- point that we compute. deriving Show connstr = ConnStr fixedp = FixedP freep = FreeP step = 0.01 deltasq = d*d where d = step verysmall = 0.000000000000001 sub3v (x,y,z) (x',y',z') = (x-x',y-y',z-z') add3v (x,y,z) (x',y',z') = (x+x',y+y',z+z') mul3vsc (x,y,z) sc = (x*sc,y*sc,z*sc) inprod (x,y,z) (x',y',z') = x*x'+y*y'+z*z' distsq a b = let d=sub3v a b in inprod d d dist a b = sqrt $ distsq a b lenv3 = dist (0,0,0) normv3 a = let d = lenv3 a n = 1/sqrt(d) in if d