title: memory error or empty returned Lists in Python
body: <p>The first function calculates the depth of a lake and has the volume as parameter. In the second one, I have to pass a volume and a time increment (that I have to increment) and it returns two lists. First List: time increments and the the last time/element in this list corresponds to the volume = 0, when the lake empty is. Second list: the corresponding depth to each time. For example for dt = 1000s seconds, z(depth) = 10m and for dt = 150000s , dt = 0m. Sorry, it's too much fluid mechanics, I just want to make it as clear as possible.
  When I call the function abfluss, it returns empty Lists when V0 is little or and it shows a memory error when v0 is bigger. I tried with many different vo and dt, I never had a filled list, it happens only when I try it without the while loop (then I have 1 element in each List). Any suggestions?</p>
  <pre class="lang-py prettyprint-override"><code>from numpy import pi
  p = 0.036
  def tiefe(V):
      a = (3*V*p**2)/pi
      z = a**(1/3)
      return z
  
  U_unten = 35.56
  A = 2                                                                       
  def abfluss(V0, dt):
      
      V_geblieben = V0 - (U_unten*A*dt)/V0
      neu_tiefe = tiefe(V_geblieben)
      t_list = []
      Z_list = []
      while V_geblieben &gt;=0:
          dt = dt+100
          t_list.append(dt)
          Z_list.append(neu_tiefe)
       
      return  t_list, Z_list
  print(abfluss(50000,3600))
  </code></pre>