Version 0.2.1

Updated Vensim translator to make use of parsimonious node visitor.

pysd/functions/functions.py

@@ -1,8 +1,4 @@
 
-# coding: utf-8
-
-# In[5]:
-
 import numpy as np
 
 def if_then_else(condition, val_if_true, val_if_false):
@@ -12,18 +8,22 @@ def if_then_else(condition, val_if_true, val_if_false):
         return val_if_false
 
 
-def step(value, tstep, t):
+def step(value, tstep):
+    t = self.components.state['t']
     return value if t >=tstep else 0
 
 
-def pulse(start, duration, t):
+def pulse(start, duration):
+    t = self.components.state['t']
     return 1 if t>=start and t<start+duration else 0
 
 # I'm not totally sure if this is correct
-def pulse_train(start, duration, repeattime, end, t):
+def pulse_train(start, duration, repeattime, end):
+    t = self.components.state['t']
     return 1 if t>=start and (t-start)%repeattime < duration else 0
 
-def ramp(slope, start, finish, t):
+def ramp(slope, start, finish):
+    t = self.components.state['t']
     if t<start:
         return 0
     elif t>finish:
@@ -40,7 +40,5 @@ def bounded_normal(minimum, maximum, mean, std, seed):
             return value
 
 
-# In[ ]:
-
 
 

pysd/translators/component_class_template.py

@@ -4,27 +4,36 @@
 
 # Todo:
 # - the __doc__ attribute isn't something that you can call, need to rework it, along with the __str_ method
-#
-#
-#
-#
-#
-#
-#
-#
-#
-#
-#
-#
-
+# it would be nice to dynamically generate the docstring (or some sortof 'help' string)
+# so that if the model is modified, the user can see the current state of modifications
 
 
 
 class component_class_template:
+    """
+    This is a template class to be subclassed and fleshed out by the translation tools.
+    The state dictionary should be expanded to include all of the model stocks.
+    
+    A function should be added for every flow or auxiliary variable, having the name of that 
+    variable, taking no parameters, which calculates the value of the variable.
+    
+    A function should be added for each stock called d<stockname>_dt() which calculates
+    the net inflow to the stock as a function of the flows.
+    
+    A function should be added for each stock called <stockname>_init() which calculates
+    the (potentially dynamically generated) initial value for the stock.
+    
+    
+    
+    This docstring will be rewritten and dynamically generated.
+    """
 
+    state = {}
+
     def __init__(self):
         self.reset_state()
 
+
     def __doc__(self):
         docstring = self.__str__ + '\n\n'
         for method in dir(self):
@@ -38,14 +47,24 @@ def __doc__(self):
                         pass
 
         return docstring
+
+
+    def initial_time(self):
+        """
+            This function represents the initial time as set in the model file
+            It should be overwritten during the class extension.
+        """
+        return 0
+
 
     def reset_state(self):
         self.t = self.initial_time() #set the initial time
 
         for key in self.state.keys():
-            self.state[key] = eval('self._'+key+'_init()') #set the initial state
+            self.state[key] = eval('self.'+key+'_init()') #set the initial state
         pass
-
+
+
     def d_dt(self, state_vector, t):
         """
             The primary purpose of this function is to interact with the integrator.
@@ -64,7 +83,11 @@ def d_dt(self, state_vector, t):
 
     def state_vector(self):
         """
-            This function interacts with the integrator by setting the initial values of the state vector.
-            It returns the values of the state dictionary, sorted alphabetically by key
+            This function interacts with the integrator by setting the 
+            initial values of the state vector.
+            
+            It returns the values of the state dictionary, sorted 
+            alphabetically by key.
             """
         return [self.state[key] for key in sorted(self.state.keys())]
+

pysd/translators/helpers.py

@@ -1,36 +1,11 @@
-import collections
-
 def clean_identifier(string):
     """
         at the moment, we may have trailing spaces on an identifier that need to be dealt with
         in the future, it would be better to improve the parser so that it handles that whitespace properly
     """
+    string = string.lower()
     string = string.strip()
     string = string.replace(' ', '_')
     return string
 
 
-
-def update(d, u):
-    """
-        Facilitates nested dictionary updating.
-        This is stolen from:
-        http://stackoverflow.com/questions/3232943/update-value-of-a-nested-dictionary-of-varying-depth
-        """
-    for k, v in u.iteritems():
-        if isinstance(v, collections.Mapping):
-            r = update(d.get(k, {}), v)
-            d[k] = r
-        else:
-            d[k] = u[k]
-    return d
-
-
-
-def getChildren(node, name):
-    """
-        Returns the children of node 'node' that are named 'name'
-        in a list.
-        """
-    return [child for child in node.children if child.expr_name == name]
-