Module Simulation
source code
Simulation 2.0 Implements SimPy Processes, Resources, Buffers, and the backbone simulation
scheduling by coroutine calls. Provides data collection through classes
Monitor and Tally.
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: - Introduced a Simulation class that now contains all global
functions for the simulation.
* Globals.py contains dummies for them to obtain backward
compatibility (Ontje Luensdorf)
- Histogram, Monitor and Tally were moved to Recording.py
(Stefan Scherfke)
- Process, SimEvent, Queue, FIFO, PriorityQ, Resource, Buffer,
Level, Store moved to Resources.py
- Renamed __Evlist to Evlist
Version:
2.0 $Revision: 163 $ $Date: 2008-12-15 12:47:44 +0100 (Mo, 15 Dez
2008) $
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requestfunc(a)
Handles 'yield request, self, res' and 'yield (request, self,
res),(<code>,self, par)'. |
source code
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getfunc(a)
Handles 'yield get, self, buffer, what, priority' and 'yield (get,
self, buffer, what, priority),(<code>,self, par)'. |
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putfunc(a)
Handles 'yield put' (simple and compound hold / waitevent) |
source code
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__TESTING = False
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version = ' 2.0 $Revision: 163 $ $Date: 2008-12-15 12:47:44 +01 ...
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hold = 1
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passivate = 2
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request = 3
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release = 4
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waitevent = 5
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queueevent = 6
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waituntil = 7
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get = 8
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put = 9
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__package__ = ' SimPy '
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Schedules Processes / semi - coroutines until time 'till'. Deprecated
since version 0.5.
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Handles 'yield request, self, res' and 'yield (request, self,
res),(<code>,self, par)'. <code > can be 'hold' or
'waitevent'.
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Handles 'yield get, self, buffer, what, priority' and 'yield (get,
self, buffer, what, priority),(<code>,self, par)'. <code >
can be 'hold' or 'waitevent'.
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version
- Value:
' 2.0 $Revision: 163 $ $Date: 2008-12-15 12:47:44 +0100 (Mo, 15 Dez 200
8) $ '
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