Package SimPy :: Module SimulationStep
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Module SimulationStep

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SimulationStep 2.0 Supports stepping through SimPy simulation event - by - event.
Based on generators (Python 2.3 and later; not 3.0)

LICENSE:
Copyright (C) 2002, 2005, 2006, 2007, 2008  Klaus G. Muller, Tony Vignaux
mailto: kgmuller@xs4all.nl and Tony.Vignaux@vuw.ac.nz

    This library is free software; you can redistribute it and / or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111 - 1307  USA
END OF LICENSE

**Change history:**

    Started out as SiPy 0.9
    
    5 / 9/2002: SiPy 0.9.1
    
        - Addition of '_cancel' method in class Process and supporting '_unpost' method in 
          class __Evlist.
        
        - Removal of redundant 'Action' method in class Process.
        
    12 / 9/2002:
    
        - Addition of resource class
        
        - Addition of '_request' and '_release' coroutine calls
        
    15 / 9/2002: moved into SimPy package
    
    16 / 9/2002:
        - Resource attributes fully implemented (resources can now have more
          than 1 shareable resource units)
        
    17 / 9/2002:
    
        - corrected removal from waitQ (Vignaux)
        
    17 / 9/2002:
    
        - added test for queue discipline in 'test_demo()'. Must be FIFO
        
    26 / 9/02: Version 0.2.0
    
        - cleaned up code; more consistent naming
        
        - prefixed all Simulation - private variable names with '_'.
        
        - prefixed all class - private variable names with '__'.
        
        - made normal exit quiet (but return message from scheduler()
        
    28 / 9/02:
    
        - included stopSimulation()
        
    15 / 10 / 02: Simulation version 0.3
    
        - Version printout now only if __TESTING
        
        - '_stop' initialized to True by module load, and set to False in 
      initialize()
        
        - Introduced 'simulate(until = 0)' instead of 'scheduler(till = 0)'. 
      Left 'scheduler()' in for backward compatibility, but marked
      as deprecated.
        
        - Added attribute 'name' to class Process; default == 'a_process'
        
        - Changed Resource constructor to 
      'def __init__(self, capacity = 1, name = 'a_resource', unitName = 'units''.
        
    13 / 11 / 02: Simulation version 0.6
    
        - Major changes to class Resource:
        
            - Added two queue types for resources, FIFO (default) and PriorityQ
            
            - Changed constructor to allow selection of queue type.
            
            - Introduced preemption of resources (to be used with PriorityQ
              queue type)
            
            - Changed constructor of class Resource to allow selection of preemption
            
            - Changes to class Process to support preemption of service
            
            - Cleaned up 'simulate' by replacing series of if - statements by dispatch table.

    19 / 11 / 02: Simulation version 0.6.1
        - Changed priority schemes so that higher values of Process 
          attribute 'priority' represent higher priority.

    20 / 11 / 02: Simulation version 0.7
        - Major change of priority approach:

            - Priority set by 'yield request, self, res, priority'

            - Priority of a Process instance associated with a specific 
              resource

    25 / 11 / 02: Simulation version 0.7.1

        - Code cleanup and optimization

        - Made process attributes remainService and preempted private 
         (_remainService and _preempted)

    11 / 12 / 2002: First process interrupt implementation

        - Addition of user methods 'interrupt' and 'resume'

        - Significant code cleanup to maintain process state

    20 / 12 / 2002: Changes to 'interrupt'; addition of boolean methods to show
                     process states

    16 / 3/2003: Changed hold (allowing posting events past _endtime)
    
    18 / 3/2003: Changed _nextev to prevent _t going past _endtime

    23 / 3/2003: Introduced new interrupt construct; deleted 'resume' method
    
    25 / 3/2003: Expanded interrupt construct:
    
        - Made 'interrupt' a method  of Process

        - Added 'interruptCause' as an attribute of an interrupted process

        - Changed definition of 'active' to 
         'self._nextTime <> None and not self._inInterrupt'

        - Cleaned up test_interrupt function

    30 / 3/2003: Modification of 'simulate':

        - error message if 'initialize' not called (fatal)

        - error message if no process scheduled (warning)

        - Ensured that upon exit from 'simulate', now() == _endtime is 
          always valid

    2 / 04 / 2003:

        - Modification of 'simulate': leave _endtime alone (undid change
          of 30 Mar 03)

        - faster '_unpost'

    3 / 04 / 2003: Made 'priority' private ('_priority')

    4 / 04 / 2003: Catch activation of non - generator error

    5 / 04 / 2003: Added 'interruptReset()' function to Process.

    7 / 04 / 2003: Changed '_unpost' to ensure that process has
                   _nextTime == None (is passive) afterwards.

    8 / 04 / 2003: Changed _hold to allow for 'yield hold, self' 
                   (equiv to 'yield hold, self, 0')

    10 / 04 / 2003: Changed 'cancel' syntax to 'Process().cancel(victim)'

    12 / 5/2003: Changed eventlist handling from dictionary to bisect
    
    9 / 6/2003: - Changed eventlist handling from pure dictionary to bisect-
                sorted 'timestamps' list of keys, resulting in greatly 
                improved performance for models with large
                numbers of event notices with differing event times.
                =========================================================
                This great change was suggested by Prof. Simon Frost. 
                Thank you, Simon! This version 1.3 is dedicated to you!
                =========================================================
              - Added import of Lister which supports well - structured 
                printing of all attributes of Process and Resource instances.

    Oct 2003: Added monitored Resource instances (Monitors for activeQ and waitQ)

    13 Dec 2003: Merged in Monitor and Histogram

    27 Feb 2004: Repaired bug in activeQ monitor of class Resource. Now actMon
                 correctly records departures from activeQ.
                 
    19 May 2004: Added erroneously omitted Histogram class.

    5 Sep 2004: Added SimEvents synchronization constructs
    
    17 Sep 2004: Added waituntil synchronization construct
    
    01 Dec 2004: SimPy version 1.5
                 Changes in this module: Repaired SimEvents bug re proc.eventsFired
                 
    12 Jan 2005: SimPy version 1.5.1
                 Changes in this module: Monitor objects now have a default name
                                         'a_Monitor'
                                         
    29 Mar 2005: Start SimPy 1.6: compound 'yield request' statements
    
    05 Jun 2005: Fixed bug in _request method -- waitMon did not work properly in
                 preemption case
                 
    09 Jun 2005: Added test in 'activate' to see whether 'initialize()' was called first.
    
    23 Aug 2005: - Added Tally data collection class
                 - Adjusted Resource to work with Tally
                 - Redid function allEventNotices() (returns prettyprinted string with event
                   times and names of process instances
                 - Added function allEventTimes (returns event times of all scheduled events)
                 
    16 Mar 2006: - Added Store and Level classes
                 - Added 'yield get' and 'yield put'
                 
    10 May 2006: - Repaired bug in Store._get method
                 - Repaired Level to allow initialBuffered have float value
                 - Added type test for Level get parameter 'nrToGet'
                 
    06 Jun 2006: - To improve pretty - printed output of 'Level' objects, changed attribute
                   _nrBuffered to nrBuffered (synonym for amount property)
                 - To improve pretty - printed output of 'Store' objects, added attribute
                   buffered (which refers to _theBuffer)
                   
    25 Aug 2006: - Start of version 1.8
                 - made 'version' public
                 - corrected condQ initialization bug
                 
    30 Sep 2006: - Introduced checks to ensure capacity of a Buffer > 0
                 - Removed from __future__ import (so Python 2.3 or later needed)
                
    15 Oct 2006: - Added code to register all Monitors and all Tallies in variables
                   'allMonitors' and 'allTallies'
                 - Added function 'startCollection' to activate Monitors and Tallies at a
                   specified time (e.g. after warmup period)
                 - Moved all test / demo programs to after 'if __name__ == '__main__':'.
                
    17 Oct 2006: - Added compound 'put' and 'get' statements for Level and Store.
    
    18 Oct 2006: - Repaired bug: self.eventsFired now gets set after an event fires
                   in a compound yield get / put with a waitevent clause (reneging case).
                   
    21 Oct 2006: - Introduced Store 'yield get' with a filter function.
                
    22 Oct 2006: - Repaired bug in prettyprinting of Store objects (the buffer 
                   content==._theBuffer was not shown) by changing ._theBuffer 
                   to .theBuffer.
                
    04 Dec 2006: - Added printHistogram method to Tally and Monitor (generates
                   table - form histogram)
                    
    07 Dec 2006: - Changed the __str__ method of Histogram to print a table 
                   (like printHistogram).
    
    18 Dec 2006: - Added trace printing of Buffers' 'unitName' for yield get and put.
    
    09 Jun 2007: - Cleaned out all uses of 'object' to prevent name clash.
    
    18 Nov 2007: - Start of 1.9 development
                 - Added 'start' method (alternative to activate) to Process
                 
    22 Nov 2007: - Major change to event list handling to speed up larger models:
                    * Drop dictionary
                    * Replace bisect by heapq
                    * Mark cancelled event notices in unpost and skip them in
                      nextev (great idea of Tony Vignaux))
                      
    4 Dec 2007: - Added twVariance calculation for both Monitor and Tally (gav)
    
    5 Dec 2007: - Changed name back to timeVariance (gav)
    
    1 Mar 2008: - Start of 1.9.1 bugfix release
                - Delete circular reference in Process instances when event 
                  notice has been processed (caused much circular garbage)
                - Added capability for multiple preempts of a process
                
    10 Aug 2008: - Removed most classes / methods and imported them from
                   Simulation.py instead (Stefan Scherfke)
                 - Moved remaining functions to SimulationStep and added some
                   methods for backward compatibility
    


Version: 2.0 $Revision: 163 $ $Date: 2008-12-15 12:47:44 +0100 (Mo, 15 Dez 2008) $

Classes [hide private]
  SimulationStep
Functions [hide private]
 
startStepping() source code
 
stopStepping() source code
 
simulate(callback=<function <lambda> at 0x012FBF70>, until=0) source code
 
simulateStep(callback=<function <lambda> at 0x0130A030>, until=0) source code
Variables [hide private]
  __TESTING = False
  version = '2.0 $Revision: 163 $ $Date: 2008-12-15 12:47:44 +01...
  _step = False
Variables Details [hide private]

version

Value:
'2.0 $Revision: 163 $ $Date: 2008-12-15 12:47:44 +0100 (Mo, 15 Dez 200\
8) $'