Parametrizing perturbagen dose-response relationships

dose_response.elm

import String
import Array
import Graphics.Input (Input, input)
import Graphics.Input.Field as Field

logistic : Float -> Float -> Float -> Float -> Float -> Float
logistic x emin emax mid slope =
  ( (emin-emax) / (1 + ((x/mid)^slope) ) ) + emax

lcurve : Float -> Float -> Float -> Path
lcurve emax mid slope =
    let
      is = [0..100]
      xs = map (\n -> (n/10-5)) is
      lfunc = (\x -> (logistic (10^x) 1 emax mid slope) * 100)
    in
      path (zip is (map lfunc xs))

emax = input Field.noContent
mid = input Field.noContent
slope = input Field.noContent

main : Signal Element
main = lift3 scene emax.signal mid.signal slope.signal

scene : Field.Content -> Field.Content -> Field.Content -> Element
scene emaxContent midContent slopeContent =
   flow down
   [ plainText "e_max:"
   , Field.field Field.defaultStyle emax.handle id "0" emaxContent
   , plainText "mid:"
   , Field.field Field.defaultStyle mid.handle id "1" midContent
   , plainText "slope:"
   , Field.field Field.defaultStyle slope.handle id "1" slopeContent
   , collage 400 400
     [ traced (solid red)
       (lcurve
         (maybe 0 id (String.toFloat emaxContent.string))
         (maybe 1 id (String.toFloat midContent.string))
         (maybe 1 id (String.toFloat slopeContent.string))
       )
     , move (50, 50) (outlined (dotted blue) (square 100))
     ]
   ]