anchor.diff:  
       let rmse sample =
           sample
  -        |> Seq.averageBy (fun (act, exp) ->
  +        |> PSeq.averageBy (fun (act, exp) ->
               let delta = act - exp
               delta * delta)
           |> sqrt
  
positive.code:     open System
      open System.IO
      open System.Text.RegularExpressions
  
      open FSharp.Collections.ParallelSeq
      open FSharp.Data
  
negative.code: 
          printfn "Loading product attributes"
  
          preprocessedAttributes
          |> Seq.groupBy (fun (id,name,value) -> id)
          |> Seq.map (fun (uid,rows) ->
              uid,
              rows
              |> Seq.map( fun (id,name,value) -> name,value)
              |> Map.ofSeq)
          |> dict
  
  