Abstract:
A mechanism for converting a graphical model of a system into an intermediate representation (IR) of a model is discussed. The mechanism alters the IR, and uses the altered IR to create a new or updated graphical model of the system that may be viewed and simulated by a user. Once the user is satisfied with the alterations to the IR, the IR or the graphical model may be used to generate code in a target language to enable the building of the physical system being designed. The use of the altered IR to generate a new or updated graphical model allows a more efficient and customizable design and simulation process than is typically found by simulating code that has been converted to target languages. The generation of the graphical model based on the altered IR allows a user to visually inspect the changes to the system, and the simulation of the graphical model based on the altered IR allows corrective action to be taken to account for any changes that occurred during the transformation of the model.

Description:
RELATED APPLICATION  
       [0001]     The present application is related to a pending U.S. patent application Ser. No. 11/130,476, filed May 16, 2005, entitled “Extensible Internal Representation of Systems With Parallel and Sequential Implementations”, the disclosure of which is incorporated by reference herein in its entirety. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The illustrative embodiment of the present invention relates generally to graphical models and more particularly to a system and method for utilizing intermediate representations of graphical models during graphical model design.  
       BACKGROUND  
       [0003]     Real-life physical systems are frequently designed with the aid of graphical computer models. The designer attempts to design the graphical model so that it represents the attributes and functionality of the system being designed. Once the designer is satisfied with the design of the graphical model, the graphical model frequently serves as the basis for code generation in a target language with the code being used to construct the physical system represented by the graphical model. An example of this process is the conversion of graphical models into VHDL, Verilog and other hardware description languages during the design of integrated circuits. The graphical model may first be converted into an intermediate representation (IR) of the graphical model before being converted into the target language.  
         [0004]     Unfortunately, the conversion of graphical models directly into a target language, with or without first converting the graphical model into an IR, suffers from a number of drawbacks. It is frequently desirable to simulate the performance of the system before building the physical model. HDL (hardware description language) simulations and other target language simulations tend to run more slowly and require more resources than simulations in a graphical programming environment. Additionally, if an IR is being used to translate the graphical model into a target language, it would be desirable to validate the translation of the graphical model into the IR and simulate a graphical model based on the IR to make sure no undesirable behavioral changes have been introduced to the model during the translation process.  
       SUMMARY OF THE INVENTION  
       [0005]     The illustrative embodiment of the present invention provides a mechanism for converting a graphical model of a system into an intermediate representation (IR) of the model, altering the IR, and then using the altered IR to create a new or updated graphical model of the system that may be viewed and simulated by a user. Once the user is satisfied with the alterations to the IR, the IR or the graphical model may be used to generate code in a target language to enable the building of the physical system being designed. The use of the altered IR to generate a new or updated graphical model allows a more efficient and customizable design and simulation process than is typically found by simulating code that has been converted to target languages. The generation of the graphical model based on the altered IR allows a user to visually inspect the changes to the system, and the simulation of the graphical model based on the altered IR allows corrective action to be taken to account for any undesirable changes that occurred during the transformation of the model.  
         [0006]     In one aspect of the present invention, a method of transforming graphical models includes the step of providing a graphical model. The method further includes the step of converting the graphical model into an intermediate representation (IR). The IR is suitable for conversion to a target language. Additionally, the method alters the IR of the graphical model and  
         [0000]     converts the altered IR into a graphical model.  
         [0007]     In another aspect of the present invention, a system for transforming graphical models, includes a graphical programming environment. The graphical programming environment includes a graphical model. The system also includes a first conversion process that converts the graphical model into an intermediate representation (IR). The IR is suitable for conversion to a target language. Additionally, the system includes a second conversion process. The second conversion process converts an altered version of the IR into a graphical model.  
         [0008]     In one aspect of the present invention, a method of transforming graphical models includes the step of providing a graphical model in a first language The method also converts the graphical model into an intermediate representation (IR). The IR is suitable for conversion to a target language different than the source language. The method additionally converts the IR into a graphical model in the target language.  
         [0009]     In one aspect of the present invention, a method of transforming graphical models includes the step of providing a graphical model in a first language. The method converts the graphical model into an intermediate representation (IR). The IR is suitable for conversion to a target language different than the source language. The method additionally converts the IR into a new graphical model in the first language and simulates the new graphical model. The method also converts the IR into a graphical model in the target language. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]     The invention is pointed out with particularity in the appended claims. The advantages of the invention described above, as well as further advantages of the invention, may be better understood by reference to the following description taken in conjunction with the accompanying drawings, in which:  
         [0011]      FIG. 1A  depicts an environment suitable for practicing the illustrative embodiment of the present invention;  
         [0012]      FIG. 1B  depicts an alternate distributed environment suitable for practicing the illustrative embodiment of the present invention;  
         [0013]      FIG. 2  is a flowchart of the sequence of steps followed by the illustrative embodiment of the present invention to convert a graphical model into an IR (intermediate representation) of the graphical model, alter the IR and convert the altered IR back into graphical model;  
         [0014]      FIG. 3  is a flowchart of the sequence of steps followed by the illustrative embodiment of the present invention to iteratively alter an IR until a graphical model satisfactory to a user is generated;  
         [0015]      FIG. 4A  is block diagram of a system;  
         [0016]      FIG. 4B  is a block diagram of the system of  FIG. 4A  following alteration to an IR based on the system;  
         [0017]      FIG. 5A  depicts an IR representation for the block diagram of  FIG. 4A ; and  
         [0018]      FIG. 5B  depicts an IR representation for the block diagram of  FIG. 4B . 
     
    
     DETAILED DESCRIPTION  
       [0019]     The computer-aided design of physical systems is an iterative process in which the designer frequently makes multiple revisions to the model before finalizing the model. The illustrative embodiment of the present invention allows these revisions to be made upon an intermediate representation (IR) of the graphical model and then converts the altered IR to a graphical model for review and simulation by the designer. The mechanism of altering the IR and then generating a new or updated graphical model based on the IR allows both the altering and review of the model to take place more efficiently and in a more customizable fashion than conventional methods of converting the graphical model into a final intended target language for review or simulation.  
         [0020]      FIG. 1A  depicts an environment suitable for practicing the illustrative embodiment of the present invention. An electronic device  2  hosts a graphical programming environment  4 . The electronic device  2  may be a desktop, workstation, mainframe, server, laptop, PDA or some other electronic device equipped with a processor and capable of hosting the graphical programming environment  4 . The graphical programming environment  4  may be a block diagram environment such as Simulink from The MathWorks, Inc. of Natick, Mass., a statechart environment such as Stateflow from The MathWorks, Inc. or a graphical circuit design environment such as Design Architect from Mentor Graphics Corporation of Wilsonville, Oreg. The graphical programming environment  4  includes a graphical model  6  such as a statechart, block diagram or electric circuit diagram. Alternatively, the graphical model could be a model of a mechanical or biological system. A first conversion process  8  on the electronic device  2  is used to create an IR  10  of the graphical model  6 . The IR  10  is a memory capture of the graphical model  6  and may be stored as a graph with nodes and edges.  
         [0021]     A transform process  12  on the electronic device  2  may be used to perform transforms that alter the IR  10 . The IR  10  may also be exposed to additional programming environments  40  such as MATLAB from The MathWorks, Inc. or LABVIEW from National Instruments of Corporation of Austin, Tex. The alteration of the IR  10  is discussed in further detail below. A second conversion process  16  is used to convert the altered IR  14  into a graphical model that is generated from the altered IR  18 . Those skilled in the art will recognize that first conversion process  8  that is used to convert the graphical model  6  into the IR  10  and the second conversion process  16  that is used to convert the altered IR  14  into the graphical model generated from the altered IR  18  may be part of the same software tool.  
         [0022]     The graphical model that is generated from the altered IR  18  may be a new graphical model or an update of the graphical model  6  that was originally used as the basis for the IR  10 . The graphical model that is generated from the altered IR  18  may be displayed and visually inspected by a user. Additionally, the graphical programming environment  4  may include a simulator  20  that may be used to simulate the operation of the physical system being modeled. A user may review the simulation to ensure the translation of the graphical model  6  into the IR did not adversely affect the system behavior and that the alterations/transformations to the IR  10  resulted in an intended result.  
         [0023]     Once the designer is satisfied with the look and performance of the graphical model generated from the altered IR  18 , the graphical model generated from the altered IR may be translated by a code generation process  22  into code in a target language such as VHDL, Verilog, SystemC, C, C++, Java or M code that is used in the construction of the physical system. Alternatively, a different code generation process  24  may used to translate the altered IR  14  directly into code in the target language. A long term storage location  30  on the electronic device  2  or accessible to the electronic device  2  may be used to store the code generated from the altered IR  32  or the code generated from the graphical model based on the altered IR  34 .  
         [0024]     Although all of the components of the present invention discussed in reference to  FIG. 1A  have been depicted as being located on a single electronic device  2 , it will be appreciated by those skilled in the art that other implementations are also possible within the scope of the present invention. For example, one or more of the graphical programming environment  4 , the additional programming environments  40 , the conversion processes  8  and  16 , code generation processes  22  and  24  and the long term storage location  30  may be in communication over a network from different physical locations.  FIG. 1B  depicts an example of an alternative distributed environment suitable for practicing the illustrative embodiment of the present invention. A client system  42  that is being accessed by a user  43  communicates over a network  44  with a server  45 . The network  44  may be the Internet, a local area network (LAN), wide area network (WAN) or some other type of network. The server hosts the graphical programming environment  4  of the present invention and a conversion software tool  46  combining the first and second conversion processes discussed in  FIG. 1A  above. Similarly, the server  45  hosts a code generation software tool  47  combining the first and second code generation processes discussed in  FIG. 1A  above. The server  45  may store the IR as a graph  48  in memory  49 . The user  43  enters commands at the client and receives output from the processing of the graphical model that is taking place on server  45 .  
         [0025]     The overall sequence of steps followed by the illustrative embodiment of the present invention in order to create a new or updated graphical model  18  based on an altered IR  14  is depicted in  FIG. 2 . The sequence begins with the provision of graphical model  6  such as a system model (step  50 ). The graphical model  6  is then converted into an IR  10  of the graphical model (step  52 ). The process by which the graphical model  6  is converted into the IR  10  is discussed further below. Once the IR  10  is created, a number of types of well-know transforms may be performed on the IR to produce an altered IR representation  14  (step  54 ). For example, the transforms may be lowering transforms, elaboration transforms or optimization transforms. The alteration of the IR may take place by exposing the IR  10  to another programming environment  40 . The altered IR  14  is then converted into a new or updated graphical model  18  (step  56 ). In an aspect of the illustrative embodiment, following the altering of the IR  10 , the second conversion process  16  generates a set of modifications that are applied to the original graphical model  6  rather than creating a new graphical model.  
         [0026]     The first conversion process  8  receives the graphical model  6  written in a source language and translates the file into an IR  10 . The IR  10  of the present invention is usually, although not required to be, in a source and target language independent format, such that data contained within the IR is not specific to the source language from which it was generated. The data contained within the IR  10  may be used for subsequent code generation and the eventual generation of a representation of the data using a target language.  
         [0027]     The first conversion process  8  is capable of converting a source language of one of a variety of types into one or more intermediate representations, such that various system models can be used to describe individual behaviors of the modeled system using the most applicable language for the desired results. The first conversion process  8  of the present invention is therefore capable of translating these various source languages into a single IR  10  for use in conversion into the target language.  
         [0028]     The translation of the source language of the graphical model  6  to the IR  10  can be completed using numerous means recognized by those skilled in the art. One suitable example is the Real-Time Workshops® (RTW) coder, offered by The MathWorks, Inc. Using the RTW coder the source language of the graphical model  6  is analyzed and converted into an IR  10  wherein the file contained within the IR is in a source and target language independent format. The RTW coder, or other suitable process, walks the graphical model data structures, retrieves the records and generates the IR. This intermediate model file includes a hierarchical structure of records describing systems and their blocks and connections analyzed from a block diagram model of the source file. One skilled in the art will readily conceive how to construct such records from the data structures of the graphical model. The use of the RTW coder is a representative example, and those skilled in the art will readily recognize that the intermediate representation can be generated using numerous coding mechanisms for processing serial and parallel source languages.  
         [0029]     Once the IR  10 , which can vary in its degree of abstraction from the graphical model, has been created from the graphical model  6 , the present invention allows the IR to be altered as part of the system design process. The altered IR  14  serves as the basis for a new or updated graphical model  18 . The designer is able to view and/or simulate the new or updated graphical model  18  to verify the behavior of the system model. The illustrative embodiment exposes the manner in which the IR is altered which allows the customization of the process by the system designer. For example, the designer is able to plug in a transform from a design environment or substitute a vendor library containing a different transform. The designer can change the operations based on the result of each design iteration. As an example, a SIMULINK block diagram model may changed to an IR, altered and changed back to a new SIMULINK model. Following simulation, the process may be repeated in the event of an unwanted result with an alteration to the new model or a replacement alteration to the original model with the process being repeated as many times as necessary.  
         [0030]      FIG. 3  depicts the iterative sequence of steps that may be followed by the present invention to allow the designer to produce an acceptable system model prior to the translation of the system model (or its IR) into a target language needed to produce the physical system. The sequence begins with the creation of the IR  10  based on the graphical model  6  (step  60 ). The IR  10  is then altered such as by applying a transform operation to the IR (step  62 ). The altered IR  14  is then converted to a graphical model  18  (step  64 ). In implementations using the Real-Time Workshop© coder discussed above, the RTW coder converts the IR back into a graphical model such as a Simulink model by examining the created hierarchical structure of records in the IR that describe systems and their blocks and connections. The information is used to create or update a block diagram model from the altered IR. The created/updated graphical model based on the altered IR  18  is then displayed to the system designer (step  66 ). The illustrative embodiment thus provides the designer the opportunity to visually inspect changes to the system model that were made to the IR, prior to the translation of the system model to a target language.  
         [0031]     If the display of the system model depicted in the graphical model based on the altered IR  18  reveals an unacceptable change to the designer (step  67 ), the process iterates and the designer may alter the IR  10  or further alter the previously altered IR  14  (step  62 ). If the visual inspection is acceptable to the designer (step  67 ) the designer may then cause the graphical programming environment  4  to simulate the graphical model based on the altered IR  18  (step  68 ). The illustrative embodiment thus also provides the system designer the opportunity to inspect the results of the simulation of the system model following changes to the IR, prior to the translation of the system model to a target language. If the simulation results are not acceptable to the system designer, the process iterates and the designer may alter the IR  10  or further alter the previously altered IR  14  (step  62 ). If the changes are acceptable to the system designer after observing the simulation results, the target language code may be generated (step  70 ), either by the code generation process  22  generating the target language code from the graphical model based on the altered IR  18  or the code generation process  24  generating the target code directly from the altered IR  14 .  
         [0032]     It will be appreciated, that the actual sequence of steps followed to utilize the IR may vary from that shown in  FIG. 3  while still remaining within the scope of the present invention. For example, following the creation of the IR and display of the graphical model based on the IR (steps  62  and  64 ), the user may decide (step  67 ) to create a new graphical model (step  60 ) rather than altering the IR (step  62 ). Alternatively, the user may choose to alter the way the IR is converted into a graphical model (step  64 ) rather than altering the actual IR (step  62 ). These and similar alternatives are expressly considered to be within the scope of the present invention.  
         [0033]     The altering of the IR  10  may take many forms and may result in behavioral changes in the model such as numerical or latency changes. Alternatively, the alteration of the IR may preserve the numerical and timing characteristics of the original model resulting in no behavioral changes.  FIGS. 4A and 4B  depict the effects of the application of a transform to a portion of an IR  10  of a system.  FIG. 4A  depicts a system  80  prior to the application of the transform. The system  80  includes a filter  82 . A lowering transform (which lowers the level of abstraction), is applied to the IR  10  of the system, specifically to the portion of the IR representing the filter  82 . The lowering transform breaks down the complicated operation of the filter  82  into simpler operations. Following the application of a lowering transform to the filter  82  in the IR  10 , the altered IR  14  is converted into a graphical model based on the altered IR  18 , specifically the system  90  represented in  FIG. 4B . The application of the lowering transform to the IR creates a simplified system  90 , wherein the filter  82  has been replaced by a series of simpler functions  92 . Those skilled in the art will recognize that there exist numerous other applicable transforms (such as optimization and elaboration transforms) for use with the current invention.  
         [0034]      FIGS. 5A and 5B  are IRs of the graphical models depicted in  FIGS. 4A and 4B  respectively.  FIG. 5A  shows an IR  100  for the system  80  depicted in  FIG. 4A . Following the application of a lowering transform to the IR  100  of the system  80 , the IR  120  of  FIG. 5B  is produced.  FIG. 5B  includes sections  122  and  126  which directly correspond to sections  102  and  106  of  FIG. 5A . The lowering transform has been applied to section  104  of the IR  100  in  FIG. 5A  to produce section  124  of  FIG. 5B . Section  104  of the IR  100  in  FIG. 5A  (the section to which the lowering transform is applied) corresponds to the filter  82  depicted in  FIG. 4A . The IR  120  in  FIG. 5B  may then be used to regenerate the graphical model of the system  90  depicted in  FIG. 4B  where the expanded filter  92  corresponds to section  124  in  FIG. 5B .  
         [0035]     In one aspect of the illustrative embodiment, the IR  10  is exposed to additional programming environments  40  such as MATLAB. The additional programming environments may allow extensibility of the transformations, vendor-specific optimizations, metrics and predictions. In another aspect of the illustrative embodiment, the transformations may be dictated by one or more user-specified configuration sets that include changes that change numerical or timing behaviors of the modeled systems. Thus the transformation may be performed by a plug-in process supplied by a vendor or a user. Alternatively, the transformation may be manually controlled and dictated by a user.  
         [0036]     The code generation processes  22  and  24  may translate the altered IR  10  (or the graphical model based on the altered IR  18 ) into the intended target language. For illustrative purposes, a single code generation process  22  or  24  have been shown resulting in a single collection of code generated from the altered IR  32  (or code generated from the graphical model based on the altered IR  34 ). It will be appreciated that the code generation processes  22  and  24  are capable of generating multiple graphical or textual programs written in a desired target language. It will be appreciated that a graphical model target language will usually be different than the original source language. The generated target file(s) can further be used to fabricate an electronic circuit using automated microprocessor manufacturing techniques understood by those skilled in the art. In another aspect of the illustrative embodiment, the code generation processes  22  and/or  24  may output a target language in C or C++ format. The target language can then be used with an external compiler to generate executable code as required.  
         [0037]     The illustrative embodiment of the present invention may also provide configurable control over access to the IR. The type of operations performed on the IR and the threshold issue of access to the IR may be set by an administrator or other authorized individual. The limitation of access to the IR can be used to impose restraints on members of the development team during the design process.  
         [0038]     Although the examples contained herein have been made with reference to a graphical modeling environment, it should be appreciated that the illustrative embodiment of the present invention may be practiced in the absence of a graphical modeling environment. Thus, a program may read a graphical model file, construct an IR, and then generate an output file without the graphical model being displayed in a graphical modeling environment.  
         [0039]     Similarly, it should be appreciated that although many of the examples contained herein have discussed the alteration of the IR, the present invention may be practiced without altering the generated IR. For example, the generation of the IR provides a user an opportunity to view the model data and structure in a different form before the generation of an output model in a different language, an option that may prove useful to the user even without any alteration of the IR. Additionally, the generation of an output model in such a scenario may be easier from the IR format than generating the output model directly from the graphical model.  
         [0040]     The present invention may be provided as one or more computer-readable programs embodied on or in one or more mediums. The mediums may be a floppy disk, a hard disk, a compact disc, a digital versatile disc, a flash memory card, a PROM, a RAM, a ROM, or a magnetic tape. In general, the computer-readable programs may be implemented in any programming language. Some examples of languages that can be used include MATLAB, C, C++, C#, or JAVA. The software programs may be stored on or in one or more mediums as object code.  
         [0041]     Since certain changes may be made without departing from the scope of the present invention, it is intended that all matter contained in the above description or shown in the accompanying drawings be interpreted as illustrative and not in a literal sense. Practitioners of the art will realize that the sequence of steps and architectures depicted in the figures may be altered without departing from the scope of the present invention and that the illustrations contained herein are singular examples of a multitude of possible depictions of the present invention.