Re: programming competition Correction

*To*: mathgroup at smc.vnet.net*Subject*: [mg4951] Re: [mg4904] programming competition Correction*From*: Allan Hayes <hay at haystack>*Date*: Mon, 7 Oct 1996 02:02:17 -0400*Sender*: owner-wri-mathgroup at wolfram.com

Please change line 6 in the code that I gave from If[n<2, {#1}, to If[n<1, {#1}, giving linearInterpolate2[ li_List, m_ ] := Block[{}, Append[ Join@@Partition[ li, 2,1, ( n=Floor[Sqrt[(#2-#1).(#2-#1)//N]/m]; If[n<1, {#1}, Table[#1 + k #2, {k,0,n}]&[#1,(#2-#1)/(n+1)], ] )& ], Last[li] ] ]; (the error crept in because of changing from Ceiling to Floor) I time it (and check it!) against the fastest code in Xah Lee's posting "[mg4900] Re: programming competition", due to espen.haslund at fys.uio.no (Espen Haslund): linearInterpolateEH2[ li_List, maxLength_ ]:= Module[{p1, p2, n}, Append[Join @@ Table[{p1, p2} = li[[{i, i+1}]]; n = Max[Ceiling[Sqrt[#.#]&[N[p2-p1]]/maxLength],1]; Table[p1+(p2-p1)j,{j,0,1-.5/n,1./n}], {i,1,Length[li]-1}], Last[li] ] ] li = Table[{Random[], Random[]}, {1000}]; maxLength = .1; a4 = Timing@ linearInterpolateEH2[ li, maxLength]; a5 = Timing@ linearInterpolate2[ li, maxLength]; First /@ {a4,a5} SameQ@@ Last /@ SetPrecision[{a4,a5},5] {21.3 Second, 14.8333 Second} True Allan Hayes hay at haystack.demon.co.uk URL:haystack.demon.co.uk ==== [MESSAGE SEPARATOR] ====