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  • 251.
    Sjölund, Martin
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
    Casella, Francesco
    Politecnico di Milano, Italy.
    Dan Iosif Pop, Adrian
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
    Asghar, Adeel
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
    Fritzson, Peter
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
    Braun, Willi
    FH Bielefeld, University of Applied Sciences, Germany.
    Ochel, Lennart
    FH Bielefeld, University of Applied Sciences, Germany.
    Bachmann, Bernhard
    FH Bielefeld, University of Applied Sciences, Germany.
    Integrated Debugging of Equation-Based Models2014Inngår i: Proceedings of the 10th International Modelica Conference / [ed] Hubertus Tummescheit and Karl-Erik Årzén, Linköping University Electronic Press, 2014, s. 195-204Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The high abstraction level of equation-based object-oriented languages (EOO) such as Modelica has the drawback that programming and modeling errors are often hard to find. In this paper we present the first integrated debugger for equation-based languages like Modelica; which can combine static and dynamic methods for run-time debugging of equation-based Modelica models during simulations. This builds on and extends previous results from a transformational static equation debugger and a dynamic debugger for the algorithmic subset of Modelica.

  • 252.
    Sjölund, Martin
    et al.
    Linköpings universitet, Institutionen för datavetenskap. Linköpings universitet, Tekniska högskolan.
    Fritzson, Peter
    Linköpings universitet, Institutionen för datavetenskap. Linköpings universitet, Tekniska högskolan.
    An OpenModelica Java External Function Interface Supporting MetaProgramming2009Inngår i: Proceedings of the 7th International Modelica Conference; Como; Italy; 20-22 September 2009 / [ed] Francesco Casella, Linköping: Linköping University Electronic Press, 2009, s. 184-192Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A complete Java interface to OpenModelica has been created; supporting both standard Modelica and the metamodeling extensions in MetaModelica. It is bidirectional; and capable of passing both standard Modelica data types; as well as abstract syntax trees and list structures to and from Java and process them in either Java or the OpenModelica Compiler. It currently uses the existing CORBA interface as well as JNI for standard Modelica. It is also capable of automatically generating the Java classes corresponding to MetaModelica code. This interface opens up increased possibilities for tool integration between OpenModelica and Java-based tools; since for example models or model fragments can be extracted from OpenModelica; processed in a Java tool; and put back into the main model representation in OpenModelica.

  • 253.
    Sjölund, Martin
    et al.
    Linköpings universitet, Institutionen för datavetenskap. Linköpings universitet, Tekniska högskolan.
    Fritzson, Peter
    Linköpings universitet, Institutionen för datavetenskap. Linköpings universitet, Tekniska högskolan.
    Debugging symbolic transformations in equation systems2011Inngår i: Proceedings of the 4th International Workshop on Equation-Based Object-Oriented Modeling Languages and Tools, EOOLT 2011, Linköping University Electronic Press , 2011, s. 67-74Konferansepaper (Fagfellevurdert)
    Abstract [en]

    How do you debug application models in an equation-based object-oriented (EOO) programming language? Compilers for these tools tend to optimize the model so heavily that it is hard to tell the origin of an equation during runtime. This work proposes and implements a prototype of a method that is efficient, yet manages to keep track of all the transformations/operations that the compiler performs on the model. The method also considers the ability to collapse certain operations so that they appear to the user as a single expandable operation. Using such a method enables makers of compilers for EOO programming languages to create debugging tools that contain sufficiently detailed information while still being appealing to the user as they minimize duplicate information.

  • 254.
    Sjölund, Martin
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
    Fritzson, Peter
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
    Pop, Adrian
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
    Bootstrapping a Compiler for an Equation-Based Object-Oriented Language2014Inngår i: Modeling, Identification and Control, ISSN 0332-7353, E-ISSN 1890-1328, Vol. 35, nr 1, s. 1-19Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    What does it mean to bootstrap a compiler, and why do it? This paper reports on the first bootstrapping of a full-scale EOO (Equation-based Object-Oriented) modeling language such as Modelica. Bootstrapping means that the compiler of a language can compile itself. However, the usual application area for the Modelica is modeling and simulation of complex physical systems. Fortunately it turns out that with some minor extensions, the Modelica language is well suited for the modeling of language semantics. We use the name MetaModelica for this slightly extended Modelica. This is a prerequisite for bootstrapping which requires that the language can be used to model and/or implement itself. The OpenModelica Compiler (OMC) has been written in this MetaModelica language. It originally supported only the standard Modelica language but has been gradually extended to also cover the MetaModelica language extensions. After substantial work, OMC is able to quickly compile itself and produces an executable with good performance. The benefits include a more extensible and maintainable compiler by introducing improved language constructs and a more powerful runtime that makes it easy to add functionality such as parser generators, debuggers, and profiling tools. Future work includes extracting and restructuring parts of OMC, making the compiler smaller and more modular and extensible. This will also make it easier to interface with OMC, making it possible to create more powerful and user-friendly OpenModelica-based tools. The compiler and its bootstrapping is a major effort -- it is currently about 330 000 lines of code, and the MetaModelica extensions are used routinely by approximately ten developers on a daily basis. 

  • 255.
    Sjölund, Martin
    et al.
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Fritzson, Peter
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Pop, Adrian
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Bootstrapping a Modelica Compiler aiming at Modelica 42011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    What does it mean to bootstrap a compiler, and why do it? This paper reports on the first bootstrapping (i.e., a compiler can compile itself) of a full-scale EOO (Equation-based Object-Oriented) modeling language such as Modelica. The Modelica language has been modeled/implemented in the OpenModelica compiler (OMC) using an extended version of Modelica called MetaModelica. OMC models the MetaModelica language and is now compiling itself with good performance. Benefits include a more extensible maintainable compiler, also making it easier to add functionality such as debugging support. This work is in line with the recently started Modelica 4 design effort which includes moving implementation of language features from the compiler to a Modelica Core library, allowing compilers to become smaller while increasing correctness and portability. A number of language constructs discussed for Modelica 4 are already supported in some form by the bootstrapped compiler. Future work includes adapting language constructs according to the Modelica 4 design effort and extracting and restructuring parts of the Modelica implementation from the OMC compiler to instead reside in a Modelica Core library, making the compiler smaller and more extensible.

  • 256.
    Sjölund, Martin
    et al.
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Gebremedhin, Mahder
    Linköpings universitet, Institutionen för datavetenskap.
    Fritzson, Peter
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Parallelizing Equation-Based Models for Simulation on Multi-Core Platforms by Utilizing Model Structure2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In today’s world of high tech manufacturing and computer-aided design simulations of models is at the heart of the whole manufacturing process. Trying to represent and study the variables of real world models using simulation computer programs can turn out to be a very expensive and time consuming task. On the other hand advancements in modern multi-core CPUs promise remarkable computational power. Modern modeling environments provide different optimization and parallelization options to take advantage of the available computational power. Some of these parallelization approaches are based on automatically extracting parallelism with the help of the model compiler or translator. Another approach is to provide the model programmers with the necessary language constructs to express any potential parallelism in their models.

    In this paper we present an automatic parallelization approach for Modelica models using Transmission Line Modeling (TLM). TLM is suitable for parallel simulations because larger models can be partitioned into smaller independent sub-models. TLM introduces parallelism into the system by decoupling subsystems using delays greater than the step size of the numerical solver. A prototype has been implemented in the OpenModelica Compiler (OMC) framework. Our approach re-uses the dependency analysis from the sequential translation step of OMC. With the help of the dependency analysis information the set of equations for a model is partitioned into a number of sub-systems. The resulting independent sub-systems are scheduled and executed in parallel. The run-time system for OMC has been improved to provide thread safety and handle parallelism while keeping the introduced overhead to minimum for normal sequential operation and maintaining portability.

  • 257.
    Stavåke, Kristian
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
    Fritzson, Peter
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
    Song, Chen
    Engineering Mathematics and Computing Laboratory, University of Heidelberg, Germany.
    Wlotzka, Martin
    Engineering Mathematics and Computing Laboratory, University of Heidelberg, Germany.
    Heuveline, Vincent
    Engineering Mathematics and Computing Laboratory, University of Heidelberg, Germany.
    PDE Modeling with Modelica via FMI import of Hiflow3 C++ Components with Parallel Multi-Core Simulations2014Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The Modelica modeling and simulation language is widely used in academia and industry to model complex, coupled dynamic systems which can be described by systems of ordinary differential equations (ODE) or differential algebraic equations (DAE). Recent work by the authors showed a way to enable partial differential equation (PDE) modeling with Modelica via functional mock-up interface (FMI) import of C++ components based on the multi-purpose finite element library HiFlow3. The finite element method (FEM) is largely used in both research and industry as a reliable technique for solving PDE problems. In contrast to methods based on language extensions or automatic semi-discretizations in space, the approach with FMI import of HiFlow3 components into Modelica requires no change to the Modelica language, enables the use of specialized PDE solvers, and it allows for full flexibility in the choice of geometry, model parameters, and space discretization between simulation runs without recompilation. However, the computationally intensive PDE solving part in this approach can form a bottleneck in the simulations. In this work, we enhance the PDE solver by using a distributed memory parallelization based on a domain decomposition. As an example application, we consider a mechanical linear elasticity problem consisting of physical forces applied on a beam. Beams, plates and shells are common elements of solid structures with a sizable quantity of application in engineering design, appearing in fuselage, ship hulls, concrete roof structure, etc. The derivation of elastic stress strain relations is a crucial point for mechanical analysis and validation, as the bending properties of the structure effects greatly the stability properties. In this work the actual beam is modeled and solved in parallelusing a C++ HiFlow3 component whereas the physical force acting on the beam is modeled using Modelica. We use the OpenModelica development environment but the same approach can be adapted to other Modelica environments.

  • 258.
    Stavåker, Kristian
    et al.
    Linköpings universitet, Institutionen för datavetenskap. Linköpings universitet, Tekniska högskolan.
    Fritzson, Peter
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Generation of Simulation Code from Equation-Based Models for Execution on CUDA-Enabled GPUs2010Inngår i: Proceedings of the 3rd Swedish Workshop on Multi-Core Computing, 2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper we present some of our work on approaches of generating simulation code from equation-based mathematical models that can be executed on parallel architectures, especially CUDA-enabled GPUs. The models are written in the objectoriented equation-based language Modelica. We show that it is possible to automatically generate simulation code for purecontinuous-time models that can be reduced to an ordinary differential equation system without algebraic loops and where the initial values of all variables and parameters are known at compile time. Implementation work has been carried out in the OpenModelica compiler (an open source implementation of a Modelica compiler). In this paper we discuss previous, ongoing, and potentially future work

  • 259.
    Stavåker, Kristian
    et al.
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Pop, Adrian
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Fritzson, Peter
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Compiling and Using Pattern Matching in Modelica2008Inngår i: Proceedings of the 6th International Modelica Conference, March 3rd-4th, 2008, University of Applied Sciences Bielefeld, Bielefeld, Germany / [ed] Bernhard Bachmann, Modelica Website: Modelica Association , 2008, s. 637-645Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Pattern matching is a well-known, powerful language feature found in functional programming languages. In this paper we present the implementation of pattern matching for Modelica. A pattern matching construct is useful for classification and decomposition of (possibly recursive) hierarchies of components such as the union type structures in the MetaModelica language extension. We argue that pattern matching not only is useful for language specification (as in the MetaModelica case) but also to write functional-style programs. One useful application is in list processing (lists are currently missing from Modelica but are part of MetaModelica). Other possible applications are in the generation of models from other models, e.g. the generation of models with uncertainty equations or models with different parameters. Another application is the generation of documentation from models and checking of guidelines or certain properties of models.

  • 260.
    Stavåker, Kristian
    et al.
    Linköpings universitet, Institutionen för datavetenskap.
    Rolls, D.
    School of Computer Science, University of Hertfordshire, United Kingdom.
    Guo, J.
    School of Computer Science, University of Hertfordshire, United Kingdom.
    Fritzson, Peter
    Linköpings universitet, Institutionen för datavetenskap.
    Scholz, S.-B.
    School of Computer Science, University of Hertfordshire, United Kingdom.
    Compilation of modelica array computations into single assignment C for efficient execution on CUDA-enabled GPUs2010Inngår i: Proceedings of the 3rd International Workshop on Equation-Based Object-Oriented Modeling Languages and Tools, EOOLT 2010 - In Conjunction with MODELS 2010 / [ed] Peter Fritzson, Edward Lee, François Cellier, David Broman, Linköping University Electronic Press , 2010, s. 81-90Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Mathematical models, derived for example from discretisation of partial differential equations, often contain operations over large arrays. In this work we investigate the possibility of compiling array operations from models in the equation-based language Modelica into Single Assignment C (SAC). The SAC2C SAC compiler can generate highly efficient code that, for instance, can be executed on CUDAenabled GPUs. We plan to enhance the open-source Modelica compiler OpenModelica, with capabilities to detect and compile data parallel Modelica for-equations/arrayequations into SAC WITH-loops. As a first step we demonstrate the feasibility of this approach by manually inserting calls to SAC array operations in the code generated from OpenModelica and show how capabilities and runtimes can be extended. As a second step we demostrate the feasibility of rewriting parts of the OpenModelica simulation runtime system in SAC. Finally, we discuss SAC2Cs switchable target architectures and demonstrate one by harnessing a CUDA-enabled GPU to improve runtimes. To the best of our knowledge, compilation of Modelica array operations for execution on CUDA-enabled GPUs is a new research area.

  • 261.
    Stavåker, Kristian
    et al.
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Ronnås, Staffan
    Heidelberg University,Germany.
    Wlotzska, Martin
    Heidelberg University,Germany.
    Heuveline, Vincent
    Heidelberg University,Germany.
    Fritzson, Peter
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    PDE Modeling with Modelica via FMI Import of HiFlow3 C++ Components2013Inngår i: SIMS 54th conference, 2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Despite an urgent need and desire in academia as well as in industry for modeling Partial Differential Equations (PDEs) using the increasingly popular Modelica modeling and simulation language, there is limited support for this available at the moment. In this work, we propose a solution based on importing PDE models with PDE solvers implemented using the general-purpose parallel finite element library HiFlow3 as models into the Modelica environment using the standard Functional Mock-up Interface. In contrast to methods based on language extensions or automatic semidiscretizations in space, this approach requires no change to the language, and enables the use of specialized PDE solvers. Furthermore, it allows for full flexibility in the choice of geometry, model parameters, and space discretization between simulation runs without recompilation needed. This makes it possible to exploit advanced features of the PDE solver, such as adaptive mesh refinement,and to build complex multi-physics simulations by coupling different models, of both PDE and DAE type, in a straightforward manner using Modelica. We illustrate our method with an example that couples a Modelica Proportional-Integral-Derivative controller to a PDE solver for the unsteady heat equation in a 3D domain.

  • 262.
    Strömberg, Dan
    et al.
    Linköpings universitet.
    Fritzson, Peter
    Linköpings universitet.
    Transfer of programs from development to runtime environments1980Inngår i: BIT Numerical Mathematics, ISSN 0006-3835, E-ISSN 1572-9125, Vol. 20, nr 4, s. 434-442Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The transfer of programs from development systems to efficient run-time environments is generally considered as a compilation process possibly followed by an optimization phase. This order excludes most possibilities to make optimizations on the source language level. This paper describes an alternative transfer method where user interaction is done on a user oriented level in order to support the optimization process. Experiments show that the efficiency gain is considerable.

  • 263. Strömberg, Lars
    et al.
    Fritzson, Peter
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Fagerström, Johan
    Linköpings universitet, Institutionen för datavetenskap. Linköpings universitet, Tekniska högskolan.
    Postmortem Debugging of Parallel Real Time Programs1991Konferansepaper (Fagfellevurdert)
  • 264.
    Suess, Jörn Guy
    et al.
    University of Queensland, Australia.
    Fritzson, Peter
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Pop, Adrian Dan Iosif
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    The Impreciseness of UML and Implications for ModelicaML2008Inngår i: EOOLT 2008 / [ed] Peter Fritzson, François Cellier, David Broman, Linköping University Electronic Press , 2008, s. 17-26Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    The Modelica community has long pursued the vision of Integrated Whole Product Modelling. This implies the ability to integrate best practice modelling languages and techniques. With ModelicaML a first step towards an open integration within the sphere of the Eclipse Modelling Framework exists. This paper argues for a development direction of ModelicaML that creates a small core with well-defined semantics, instead of the current version that is based on an extension of SysML. To this end, modelling standards and their practicabilities are discussed and exemplified through a usage scenario.

  • 265.
    Süss, Jörn Guy
    et al.
    School of Information Technology and Electrical Engineering The University of Queensland.
    Pop, Adrian Dan Iosif
    Linköpings universitet, Institutionen för datavetenskap.
    Fritzson, Peter
    Linköpings universitet, Institutionen för datavetenskap.
    Wildman, Luke
    School of Information Technology and Electrical Engineering The University of Queensland.
    Towards Integrated Model-Driven Testing of SCADA Systems Using the Eclipse Modeling Framework and Modelica2008Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Testing SCADA (Supervisory Control And Data Acquisition) near real-time systems is challenging, as it involves complex interactions and the simulation of the supervised and controlled environment. Model-driven testing techniques can help to achieve clarity about the inner workings of the system and facilitate test construction, but these models are currently disconnected from those of the environmental simulation, leading to a paradigm break. This paper presents a strategy to remedy this situation. To this end, it leverages Modelica and the Eclipse Modeling Framework.Modelica is an object-oriented mathematical modeling language for component-oriented modeling of complex physical systems. It is an open standard and implementation, and provides a rendering of its input language in Ecore, the meta-language of the Eclipse Model-ing Framework (EMF). It also offers convenient visual editors, whose notation via the ModelicaML profile is consistent with the SysML standard, a restricted version of UMLThe strategy presented here leverages EMF as a common basis for model-driven development, reusing Modelica-s powerful simulation features in integration with a custom-designed testing process. With this tool-ing, a test engineer can model all aspects of a SCADA test within one workbench and enjoy full traceability between the proprietary test model, and its surrounding environment simulation.

  • 266.
    Thiele, Bernhard Amadeus
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
    Knoll, A.
    Technical University of Munich, Germany.
    Fritzson, Peter
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
    Towards Qualifiable Code Generation from a Clocked Synchronous Subset of Modelica2015Inngår i: Modeling, Identification and Control, ISSN 0332-7353, E-ISSN 1890-1328, Vol. 36, nr 1, s. 23-52Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    So far no qualifiable automatic code generators (ACGs) are available for Modelica. Hence, digital control applications can be modeled and simulated in Modelica, but require tedious additional efforts (e.g., manual reprogramming) to produce qualifiable target system production code. In order to more fully leverage the potential of a model-based development (MBD) process in Modelica, a qualifiable automatic code generator is needed. Typical Modelica code generation is a fairly complex process which imposes a huge development burden to any efforts of tool qualification. This work aims at mapping a Modelica subset for digital control function development to a well-understood synchronous data-flow kernel language. This kernel language allows to resort to established compilation techniques for data-flow languages which are understood enough to be accepted by certification authorities. The mapping is established by providing a translational semantics from the Modelica subset to the synchronous data-flow kernel language. However, this translation turned out to be more intricate than initially expected and has given rise to several interesting issues that require suitable design decisions regarding the mapping and the language subset.

  • 267.
    Thiele, Bernhard
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten.
    Pop, Adrian
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten.
    Fritzson, Peter
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten.
    Flattening of Modelica State Machines: a practical symbolic representation2015Inngår i: Proceedings of the 11th International Modelica Conference: Versailles, France, September 21-23, 2015 / [ed] Peter Fritzson, Hilding Elmqvist, Linköping: Linköping University Electronic Press, 2015, s. 255-263Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Modelica 3.3 introduced dedicated built-in language support for state machines that was inspired by semantics known from Statechart and mode automata formalisms. The specification describes the semantics of these constructs in terms of data-flow equations that allows to relate it to the Modelica DAE representation which is the conceptual intermediate format of Modelica code after instance creation (flattening). However, a complete transformation of state machine constructs into data-flow equations at the stage of flattening requires an early commitment to implementation details that potentially hinders model optimizations at subsequent translation phases. Also, due to the required substantial model transformation the semantic distance between the original source model and the flattened representation is rather large. Hence, this paper proposes a more versatile symbolic representation for flattened state machine constructs that preserves the state machine’s composition structure and allows postponing optimizations to subsequent compiler phases.

  • 268.
    Torabzadeh-Tari, Mohsen
    et al.
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Fritzson, Peter
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Pop, Adrian
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Sjölund, Martin
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Generalization of an Active Electronic Notebook for Teaching Multiple Programming Languages2010Inngår i: IEEE EDUCON Education Engineering 2010 – The Future of Global Learning Engineering Education: Learning Environments and Ecosystems in Engineering Education, 2010, s. 1083-1084Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper we present a generalization of the active electronic notebook, OMNotebook, for handling multiple programming languages for educational purposes. OMNotebook can be an alternative or complementary tool to the traditional teaching method with lecturing and reading textbooks. Experience shows that using such an electronic book will lead to more engagement from the students. OMNotebook can contain technical computations and text, as well as graphics. Hence it is a suitable tool for teaching, experimentation, simulation, scripting, model documentation, storage, etc. OMNotebook is part of the open source platform OpenModelica. It is already used for the course material DrModelica in teaching the Modelica language but can easily be adapted to other programming languages which is also shown in this paper. The notebook can also be adapted to other areas, such as physics, chemistry, biology, biomechanics etc., where phenomena can be illustrated by dynamic simulations within the notebook. The idea behind this paper is to show that by using a standardized interface the notebook can be extended to any computer language, i.e., being language independent. This is shown in the form of an implementation and adaptation of the notebook to support the Scheme language.

  • 269.
    Torabzadeh-Tari, Mohsen
    et al.
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Fritzson, Peter
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Sjölund, Martin
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Pop, Adrian
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    OpenModelica-Python Interoperability Applied to Monte Carlo Simulation2009Inngår i: Proceedings of the 50th Scandinavian Conference on Simulation and Modeling, 2009Konferansepaper (Fagfellevurdert)
  • 270.
    Torabzadeh-Tari, Mohsen
    et al.
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Remala, Jhansi Reddy
    Linköpings universitet, Institutionen för datavetenskap. Linköpings universitet, Tekniska högskolan.
    Sjölund, Martin
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Pop, Adrian
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Fritzson, Peter
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    OMSketch — Graphical Sketching in the OpenModelica Interactive Book, OMNotebook2011Konferansepaper (Fagfellevurdert)
    Abstract [sv]

    In this paper we present a new functionality for graphical sketching in the OpenModelica interactive book, OMNotebook, which is part of the OpenModelica environment and used mainly for teaching. The new functionality is called OMSketch and allows the user to edit and draw shapes and figures within the electronic book. This allows teachers to prepare more pedagogic course material and stu-dents to make graphical notes in addition to the currenttextual ones.

    The active electronic notebook, OMNotebook, is already used as basis for two course materials, DrModelica and DrControl for teaching the Modelica languages and control theory respectively. Electronic notebooks can be an alternative or complement compared to the traditional teaching me-thod with lecturing and reading textbooks. Experience shows that using such an electronic book will lead to more engagement from the students. OMNotebook can contain interactive technical computations and text, as well as graphics. Hence it is a suitable tool for teaching, experimentation, simu-lation, scripting, model documentation, storage, etc.

  • 271.
    Torabzadeh-Tari, Mohsen
    et al.
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Sjölund, Martin
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Pop, Adrian
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Fritzson, Peter
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    DrControl: An Interactive Course Material for  Teaching Control Engineering2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper we present an interactive course material called DrControl for teaching control theory concepts mixed together with exercises and example models in Modelica. The active electronic notebook, OMNotebook, is the basis for the course material. This can be an alternative or complement compared to the traditional teaching method with lecturing and reading textbooks. Experience shows that using such an electronic book will lead to more engagement from the students. OMNotebook can contain interactive technical computations and text, as well as graphics. Hence it is a suitable tool for teaching, experimentation, simulation, scripting, model documentation, storage, etc.

  • 272.
    Tundis, Andrea
    et al.
    University of Calabria, Italy.
    Rogovchenko, Lena
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Garro, Alfredo
    University of Calabria, Italy.
    Nyberg, Mattias
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Fritzson, Peter
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Performing Fault Tree Analysis of a Modelica-Based System Design Through a Probability Model2013Konferansepaper (Fagfellevurdert)
  • 273.
    Viklund, Lars
    et al.
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Fritzson, Peter
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    An object-oriented language for symbolic computation—applied to machine element analysis1992Inngår i: ISSAC’92, ACM Digital Library, 1992, s. 397-405Konferansepaper (Fagfellevurdert)
  • 274.
    Viklund, Lars
    et al.
    Linköpings universitet, Institutionen för datavetenskap. Linköpings universitet, Tekniska högskolan.
    Fritzson, Peter
    Linköpings universitet, Institutionen för datavetenskap. Linköpings universitet, Tekniska högskolan.
    ObjectMath – An Object-Oriented Language and Environment for Symbolic and Numerical Processing in Scientific Computing1995Inngår i: Scientific Programming, ISSN 1058-9244, E-ISSN 1875-919X, Vol. 4, nr 4, s. 229-250Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    ObjectMath is a language for scientific computing that integrates object-oriented constructs with features for symbolic and numerical computation. Using ObjectMath, complex mathematical models may be implemented in a natural way. The ObjectMath programming environment provides tools for generating efficient numerical code from such models. Symbolic computation is used to rewrite and simplify equations before code is generated. One novelty of the ObjectMath approach is that it provides a comman language and an integrated environment for this kind of mixed symbolic/numerical computation. The motivation for this work is the current low-level state of the art in programming for scientific computing. Much numerical software is still being developed the traditional way in Fortran. This is especially true in application areas such as machine elements analysis, where complex nonlinear problems are the norm. We believe that tools like ObjectMath can increase productivity and quality, thus enabling users to solve problems that are too complex to handle with traditional tools. 

  • 275.
    Viklund, Lars
    et al.
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Herber, Johan
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Fritzson, Peter
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    The Implementation of ObjectMath - A High-Level Programming Environment for Scientific Computing1992Inngår i: Compiler Construction, Springer Berlin/Heidelberg, 1992, s. 312-318Konferansepaper (Fagfellevurdert)
  • 276.
    Westman, Rickard
    et al.
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Fritzson, Peter
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Graphical user interfaces for algorithmic debugging1993Inngår i: Automated and Algorithmic Debugging, Springer Berlin/Heidelberg, 1993, s. 273-286Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Algorithmic Debugging is a method for semi-automatic program debugging, where the debugger incrementally acquires knowledge about the debugged program by interacting with the user. However, a major obstacle that prevents large-scale use of the method is the large number of questions (sometimes hard to answer) put to the user. One important improvement would be to provide a graphical user interface (GUI) for algorithmic debugging that provides context and additional information that makes it easier for the user to answer questions, and is flexible enough to let the user postpone answering certain questions and to a greater extent control where to look for the bug. In this paper we discuss several of these issues, and present a prototype graphical user interface that has been implemented and used as a part of a generalized algorithmic debugger for imperative languages, and recently adapted to an algorithmic debugger for lazy functional languages.

  • 277.
    Wrangsjö, Andreas
    et al.
    Linköpings universitet, Institutionen för datavetenskap. Linköpings universitet, Tekniska högskolan.
    Fritzson, Peter
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Sheshadri, Krishnamurthy
    Linköpings universitet, Institutionen för datavetenskap. Linköpings universitet, Tekniska högskolan.
    Transforming Systems of PDEs for Efficient Numerical Solution1999Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A Mathematica package to deal with a system of partial differential equations (PDEs) is presented. This package usesexplicit finite−difference schemes to handle equations in an arbitrary number of variables that are functions of onespatial variable and time. The code has the flexibility to incorporate any difference approximation specified by theuser, and transforms the given system of PDEs into a system of difference equations that can be iteratively solved using the discretized forms of initial and boundary conditions. The iteration is made considerably faster by converting the Mathematica code into an optimized C++ code using the MathCode C++ compiler[1]. Examples are presented in which the generated C++ code runs about a thousand times faster than the Mathematica code.

  • 278.
    Zuhdy, Beshar
    et al.
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Fritzson, Peter
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Engström, Kent
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Implementation of the real-time functional language Erlang on a massively parallel platform, with applications to telecommunications services1995Inngår i: High-Performance Computing and Networking, Springer, 1995, s. 886-891Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Many real-time systems need large amounts of computational power. This may soon provide a larger market for parallel computers than the scientific computing area where most of them are used today. Examples of new and interesting areas are telephone switching systems, image recognition, real-time databases, multi-media services and traffic guidance systems. Programming parallel computers for these new applications is often complex and error-phrone. To alleviate this condition, Ericsson has developed a new non-lazy functional programming language called Erlang. This new language, which has already been used in several large projects, was designed to provide a good environment for building large fault-tolerant real-time applications with explicit concurrency.

    Existing Erlang implementations run on SISD computers. Together with Ericsson, we have developed a MIMD version of Erlang, initially for the Parsytec GC/PowerPlus. This is one of the first implementations of a functional language used in industry on a MIMD computer. To benchmark the parallel Erlang version, we are using a telecommunications application developed by Ericsson.

  • 279.
    Östlund, Per
    et al.
    Linköpings universitet, Institutionen för datavetenskap. Linköpings universitet, Tekniska högskolan.
    Stavåker, Kristian
    Linköpings universitet, Institutionen för datavetenskap. Linköpings universitet, Tekniska högskolan.
    Fritzson, Peter
    Linköpings universitet, Institutionen för datavetenskap, PELAB - Laboratoriet för programmeringsomgivningar. Linköpings universitet, Tekniska högskolan.
    Parallel Simulation of Equation-Based Models on CUDA-Enabled GPUs2010Inngår i: Proceedings of the 9th Workshop on Parallel/High-Performance Object-Oriented Scientific Computing POOSC '10, New York, USA: ACM , 2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Our contributions with this work are methods and a prototype implementation for compiling and executing a limited set of equation-based mathematical models (written in the object-oriented equation-based modeling language Modelica) on CUDA-enabled GPUs. We look at methods of finding parallelism in Modelica models, that can be used on the massively parallel CUDA architecture. The methods have been implemented in a new back-end module of the OpenModelica compiler (an open-source Modelica compiler). This paper shows that it is possible to automatically generate simulation code for pure continuous-time models that can be reduced to an ordinary differential equation system without algebraic loops and where the initial values of all variables and parameters are known at compile time. It is possible to get some speedup compared with simulation on a single CPU core, a (approximated) relative speedup of 4.6 was for instance obtained for one model.

3456 251 - 279 of 279
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