PTOLEMY DOMAINS AND BASIC OPERATIONS

1. SIMULATION DOMAINS

• Synchronous dataflow (SDF)
  
• Boolean dataflow (BDF)
  
• Dynamic dataflow (DDF)
  
• Process Network (PN)
  
• Discrete Event (DE)
  
• Multidimensional Synchronous dataflow (MDSDF)
  
  

2. Simulation Domain Presentation: SDF      *

• Synchronous dataflow (SDF)
  
• the oldest and most mature domain
  
• about 500 stars available
  
• suitable for :
  
  • digital filtering (fixed or adaptive, in time or frequency domain, real and complex filters, ...)
    
  • speech coding and sound synthesis
    
  • image processing and video coding
    
  • sample rate conversion and multiple rate applications
    
  • analysis and synthesis filter banks
    
  • modems
    
  • phase-locked loops
    
  • channel simulation
    
  • linear prediction and Kalman filtering
    
  • spectral estimation, ....
    
  • all pure signal processing with or without sampling rate change
    
    

3. Simulation Domain Presentation: BDF

Boolean dataflow (BDF)

• like DDF, also a run-time flow of control
  
• unlike DDF attempts to construct compile-time schedule
  
  • mechanism = annotated schedule, ie a static schedule where each firing is annotated with the Boolean condition under which it occurs; the Boolean values are computed during the execution
    
  • does not support recursion
    
  • applications are the same as those of DDF
    
  • SDF is a subdomain of BDF, which is a subdomain of DDF
    
    

4. Simulation Domain Presentation: DDF

Dynamic dataflow (DDF)

• dynamic (run time) scheduling and flow of control
  
• allows data-dependent  iteration, true recursion and simulation of systems with multiple modes of operation
  
• typical examples:
  
  • modems implementing multiple standards
    
  • signal coding algorithms with a range of compression scheme
    
  • asynchronous signal processing such as timing recovery and arbitrary sample rate conversion
    
  • clock recovery system in radiocommunication
    
• SDF is a subdomain of DDF
  Simulation domains:DDF
  
  

5. Simulation Domain Presentation: PN

Process Network (PN)

• implementation of Kahn process networks, a generalization of dataflow, where dataflow actors become dataflow processes
  
• implemented using POSIX threads
  
• PN systems can run in parallel on multiprocessor workstations with appropriate OS support for threads
  
• SDF, BDF nad DDF are subdomains of PN
  
• still an experimental domain
  
  

6. Simulation Domain Presentation: DE

Discrete Event (DE) = Time domain

• each data has an associated time stamp
  
• event driven model of computation
  
• a scheduler maintains the event queue
  
• simultaneous events  are handled in a consistent way
  
• suitable for
  
  • high-level modeling of communication networks (packet switched networks, wireless networks)
    
  • hardware systems and queuing systems
    
  • multimedia systems
    
  • transportation networks
    
  • synchronizing a simulation to a real-time clock
    
• can be used in  combination with SDF, BDF, DDF or PN domains
  
  

7. Simulation Domain Presentation: MDSDF

Multidimensionnal Synchronous Dataflow (MDSDF)

• still new and experimental domain
  
• extension of the SDF to multidimensional streams
  
• greater variety of dataflow schedule in a graphically compact way
  
• potentially can reveal data parallelism
  
• current implementation limited to two dimensional streams
  
  

8. What is a wormhole ?

by definition a wormhole is a star from a particular domain that internally contains a galaxy from another domain

• it allows domains to be nested and mixed
  
  

9. CODE GENERATION DOMAINS

• Code Generation Domains
  
• Code Generation in C (CGC)
  
• Code Generation for Motorola 56000 (CG56)
  
• Code Generation for TMS320C50 (CG320C50)
  
• Code Generation for VHDL (CGVHDL)
  
• Code Generation Domain: CGC
  
• Code Generation in C (CGC)
  
  • the most mature code generation model
    
  • can generate code for SDF, DDF, and BDF models
    
  • generate code for having the simulation working on many processors
    
  • handles automatically the parallelisation of the code (for multi DSP boards)
    
  • !! does not handle message structures !!
    
  • (just built in data types)
    
    

10. Code Generation Domain: CG56

Code Generation in assembly code for Motorola 56000 DSP (CG56)

• support only SDF systems
  
• possibility to have the generated code  running on a real DSP board connected  to the station, and to have some stimuli coming from a SDF simulation
  
• used for example:
  
  • for real-time implementation of various modem standards,
    
  • for touchtone generators, touchtone decoders
    
• but resulting code not very efficient for elementary operations
  
• !! old development stopped !!
  
  

11. Code generation: CG320C50

same principles as CG56 but for TMS320C50
named CG320C50 starting from release 0.7

12. Code generation in VHDL VHDL

• supports only SDF systems
  
  • for modeling systems at the functional block level, independently of implementation issues:
    
    • DSP functions for filtering and transforms
      
    • digital logic functions
      
  • different targets are available for different styles of VHDL, behavioural or structural (for VSS, for Model TechVHDL simulator)
    
  • no bit or bit vector available
    
  • co-simulation between a VHDL simulator and Ptolemy is possible
    
    

13. Code Generation Domain: CGVHDLB

• supports behavioral models using native VHDL discrete event model of computation
  
•   for modeling the behaviour of the components and their interaction at all levels of abstraction
  
  

13. What is a target ?

• a target is related to a domain
  
• a target is a structure used to control
  
  • either the execution and scheduling of a simulation ( in case of a simulation domain )
    
  • or the code generation, scheduling, compilation and execution ( in case of a code generation domain )
    
• each target has a different behaviour / principle
  
• each target has its own parameters
  
• targets can be changed / edited by the user ('T')
  
  

14. Ptolemy Terminology

• a domain of simulation is considered as an object defining the model of computation, which defines the behavior of a network of blocks
  
• a domain of code generation corresponds to a single target language
  
  

15. Ptolemy Terminology

• a star is the lowest level of block in Ptolemy
  
• a galaxy is a block made up of connected sub-blocks, with inputs and/or output
  
• a universe is an outermost block representing a complete system that the user can run
  
  

15. Ptolemy Terminology

• a schematic is a block diagram, at any level
  
• a palette is a design object that contains a library of icons rather than a schematic
  
• a facet is a design object, either a schematic or a palette
  Related utilities
  used to display simulation results:
  
• Xgraph: for curves
  
• Xv: for static images
  
• URT: for moving pictures
  
• ptplay: for sounds
  
• if Matlab license available: for any curve or static image plotting
  
  

16. Designing a universe: workflow

17. Creating a universe: step by step

• open main palettes ('O')
  
• open needed palettes ('i')
  
• open new facet window with universe name ('F')
  
• build schematic with existing stars and galaxies
  
  • select blocks and place them on schematic
    
  • connect them to each others
    
  • add signal sources and display blocks
    
• edit star parameters ('e')
  
• save schematic ('S')
  
• check result and run simulation ('R')
  
• Designing a galaxy: workflow
  
  

18. Creating a galaxy: step by step

• open main palettes ('O')
  
• open needed palettes ('i')
  
• open new facet window with galaxy name ('F')
  
• build schematic with existing stars
  
  • select blocks and connect them
    
  • add wires for inputs / outputs
    
  • give them a name ("name" then 'c')
    
• edit star parameters (',')
  
• save schematic ('S')
  
• create galaxy ('@') and give related palette name
  
• check in the given palette the presence of the created block
  
  

19. PTOLEMY Basic commands

Window management
F	"Facet": open facet or new/existing schematic
O	"open" palette list
CTRL-D	"quit" window
Schematic creation
c	"create" a new block or  wire name
i	"inside": look at palette or block content
S	"save" a schematic
Schematic edition
e	"edit" the parameters of a block
Simulation
R	"run" the simulation of current schematic

20. Ptolemy basic commands for creating a schematic

Window management
F	"Facet": open facet/schematic
O	"open" palette list
z	"zoom" in a window
Z	"zoom" out a window
p	"pan" a window
CTRL-D	"quit window
Schematic creation
c	"create" a new block or wire name
i	"inside": look at palette or block content
s	"select" a block
u	deselect a block
m	"move" a block
S	"save" a schematic
Schematic edition
e	"edit" the parameters of a block
,	show the description of a block
<-	delete a line or a box
D	"delete" a pointed block or wire
Simulation
*	make new star
@	create a star / galaxy from a schematic
R	"run" the simulation of current schematic

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07/02/00

PTOLAB

Copyright Arnaud LAPREVOTE & FREE&ALTER SOFT 1997-2000 - Right to copy, distribute, modify electronically the electronic form is given to anybody. Commercial reproductions on paper vorbidden without written autorisation of Arnaud LAPREVOTE