Code

Sleep Model

 globals [y
          Tgem
          start
          T
          p
          rc
          x
          R
          time
          stage
          test]
 
 to Setup
   clear-all
   set y 100
   set Tgem (90 * 60)
   reset-ticks
 end
 
 to Go
   foreach [1 2] [
     set start y
     set T -1
     while [T < 0] [set T (random-normal Tgem 1800)]
     set p (random-float 1.0)
     set rc (4 / (1 + exp((ticks - (2.5 * Tgem)) / 20000)) - 2)
     ifelse rc > 0
       [set x (0.5 - (1 / rc) + sqrt((2.0 / rc) * p + (rc ^ -2) - (rc ^ -1) + 0.25))]
       [set x (0.5 - (1 / rc) - sqrt((2.0 / rc) * p + (rc ^ -2) - (rc ^ -1) + 0.25))]
     ifelse ? = 1
       [set R (x * start / 2)]
       [set R ((x - 1) * (100 - start) / 2)]
     set time (n-values (T / 2) [?])
     foreach time [
       set y (R * (cos (360 * ? / T)) + start - R)
       set stage ((y - (y mod 25)) / 25 - 3)
       set test (1 / (1 + exp(ticks)))
       tick
     ]
   ]
 end