code/steam_model.py

   1 #
   2 # 20,000 Light Years Into Space
   3 # This game is licensed under GPL v2, and copyright (C) Jack Whitham 2006-07.
   4 #
   5
   6 # A model for the movement of steam within the system.
   7
   8
   9 from primitives import *
  10
  11
  12 class Voltage_Model:
  13     # Don't understand steam? Confused by the thought of
  14     # boiling water being used as a source of energy?
  15     # Why not just assume that it's electricity.
  16
  17     def __init__(self,node):
  18         # Invariant:
  19         self.capacitance = 1.0
  20         # May change:
  21         self.charge = 0.0
  22         self.voltage = 0.0
  23         # Changed by upgrades
  24         self.capacity = INITIAL_NODE_CAPACITY
  25         self.node = node
  26
  27     NEGLIGIBLE = 0.05
  28     TIME_CONSTANT = 0.1
  29
  30     def Source(self, current):
  31         dq = current * self.TIME_CONSTANT
  32         self.charge += dq
  33         self.__Bound()
  34
  35     def Think(self, neighbour_list):
  36         self.voltage = self.charge / self.capacitance
  37         currents = []
  38
  39         for (neighbour, resist, max_intensity) in neighbour_list:
  40             dir = 0
  41             # Potential difference:
  42             dv = self.voltage - neighbour.voltage
  43             if ( dv >= self.NEGLIGIBLE ):
  44                 # Current flow:
  45                 if (resist<1.0):
  46                   resist=1.0
  47
  48                 i = dv / resist
  49                 # Charge flow:
  50                 dq = i * self.TIME_CONSTANT
  51
  52                 adq=math.fabs(dq);
  53                 if (adq>1): dq/=math.sqrt(adq)  # Limit accurracy problems
  54                 # Apply Intensity Limit
  55                 if (dq>max_intensity*self.TIME_CONSTANT):
  56                     dq=max_intensity*self.TIME_CONSTANT
  57
  58                 if (dq<-max_intensity*self.TIME_CONSTANT):
  59                     dq=-max_intensity*self.TIME_CONSTANT
  60
  61                 if ( self.charge-dq > self.capacity ):
  62                     dq=self.charge-self.capacity
  63                 if ( neighbour.charge+dq > neighbour.capacity ):
  64                     dq=neighbour.capacity-neighbour.charge
  65
  66                 i = dq / self.TIME_CONSTANT
  67
  68
  69                 self.charge -= dq
  70                 neighbour.charge += dq
  71                 currents.append(i)
  72             else:
  73                 currents.append(0.0)
  74         self.__Bound()
  75         return currents
  76
  77     def __Bound(self):
  78         original_charge=self.charge
  79         if ( self.charge < 0 ):
  80             self.charge = 0
  81         elif ( self.charge > self.capacity ):
  82             self.charge = self.capacity # vent
  83
  84         diff_charge=original_charge-self.charge
  85
  86         if len(self.node.pipes)>0:
  87             diff_charge/=len(self.node.pipes)
  88
  89             for pipe in self.node.pipes:
  90                 if pipe.n1==self.node: dest=pipe.n2
  91                 if pipe.n2==self.node: dest=pipe.n1
  92                 dest.steam.charge+=diff_charge
  93
  94
  95
  96     def Get_Pressure(self):
  97         return self.charge
  98
  99     def Get_Capacity(self):
 100         return self.capacity
 101
 102     def Capacity_Upgrade(self):
 103         self.capacity += CAPACITY_UPGRADE
 104
 105 class Steam_Model(Voltage_Model):
 106     pass
 107