The Experts below are selected from a list of 108180 Experts worldwide ranked by ideXlab platform
Frederik De Ceuster - One of the best experts on this subject based on the ideXlab platform.
-
magritte a modern Software Library for 3d radiative transfer ii adaptive ray tracing mesh construction and reduction
Monthly Notices of the Royal Astronomical Society, 2020Co-Authors: Frederik De Ceuster, W Homan, Jeremy Yates, L Decin, J Bolte, Silke Maes, Jolien Malfait, P A BoyleAbstract:Radiative transfer is a notoriously difficult and computationally demanding problem. Yet, it is an indispensable ingredient in nearly all astrophysical and cosmological simulations. Choosing an appropriate discretization scheme is a crucial part of the simulation, since it not only determines the direct memory cost of the model but also largely determines the computational cost and the achievable accuracy. In this paper, we show how an appropriate choice of directional discretization scheme as well as spatial model mesh can help alleviate the computational cost, while largely retaining the accuracy. First, we discuss the adaptive ray-tracing scheme implemented in our 3D radiative transfer Library Magritte, that adapts the rays to the spatial mesh and uses a hierarchical directional discretization based on HEALPix. Second, we demonstrate how the free and open-source Software Library Gmsh can be used to generate high quality meshes that can be easily tailored for Magritte. In particular, we show how the local element size distribution of the mesh can be used to optimise the sampling of both analytically and numerically defined models. Furthermore, we show that when using the output of hydrodynamics simulations as input for a radiative transfer simulation, the number of elements in the input model can often be reduced by an order of magnitude, without significant loss of accuracy in the radiation field. We demonstrate this for two models based on a hierarchical octree mesh resulting from adaptive mesh refinement (AMR), as well as two models based on smoothed-particle hydrodynamics (SPH) data.
-
magritte a modern Software Library for 3d radiative transfer i non lte atomic and molecular line modelling
Monthly Notices of the Royal Astronomical Society, 2020Co-Authors: Frederik De Ceuster, W Homan, Jeremy Yates, L Decin, P A Boyle, James HetheringtonAbstract:Radiative transfer is a key component in almost all astrophysical and cosmological simulations. We present Magritte: a modern open-source Software Library for 3D radiative transfer. It uses a deterministic ray-tracer and formal solver, i.e. it computes the radiation field by tracing rays through the model and solving the radiative transfer equation in its second-order form along a fixed set of rays originating from each point. Magritte can handle structured and unstructured input meshes, as well as smoothed-particle hydrodynamics (SPH) particle data. In this first paper, we describe the numerical implementation, semi-analytic tests and cross-code benchmarks for the non-LTE line radiative transfer module of Magritte. This module uses the radiative transfer solver to self-consistently determine the populations of the quantised energy levels of atoms and molecules using an accelerated Lambda iteration (ALI) scheme. We compare Magritte with the established radiative transfer solvers Ratran (1D) and Lime (3D) on the van Zadelhoff benchmark and present a first application to a simple Keplerian disc model. Comparing with Lime, we conclude that Magritte produces more accurate and more precise results, especially at high optical depth, and that it is faster.
James Hetherington - One of the best experts on this subject based on the ideXlab platform.
-
magritte a modern Software Library for 3d radiative transfer i non lte atomic and molecular line modelling
Monthly Notices of the Royal Astronomical Society, 2020Co-Authors: Frederik De Ceuster, W Homan, Jeremy Yates, L Decin, P A Boyle, James HetheringtonAbstract:Radiative transfer is a key component in almost all astrophysical and cosmological simulations. We present Magritte: a modern open-source Software Library for 3D radiative transfer. It uses a deterministic ray-tracer and formal solver, i.e. it computes the radiation field by tracing rays through the model and solving the radiative transfer equation in its second-order form along a fixed set of rays originating from each point. Magritte can handle structured and unstructured input meshes, as well as smoothed-particle hydrodynamics (SPH) particle data. In this first paper, we describe the numerical implementation, semi-analytic tests and cross-code benchmarks for the non-LTE line radiative transfer module of Magritte. This module uses the radiative transfer solver to self-consistently determine the populations of the quantised energy levels of atoms and molecules using an accelerated Lambda iteration (ALI) scheme. We compare Magritte with the established radiative transfer solvers Ratran (1D) and Lime (3D) on the van Zadelhoff benchmark and present a first application to a simple Keplerian disc model. Comparing with Lime, we conclude that Magritte produces more accurate and more precise results, especially at high optical depth, and that it is faster.
L Decin - One of the best experts on this subject based on the ideXlab platform.
-
magritte a modern Software Library for 3d radiative transfer ii adaptive ray tracing mesh construction and reduction
Monthly Notices of the Royal Astronomical Society, 2020Co-Authors: Frederik De Ceuster, W Homan, Jeremy Yates, L Decin, J Bolte, Silke Maes, Jolien Malfait, P A BoyleAbstract:Radiative transfer is a notoriously difficult and computationally demanding problem. Yet, it is an indispensable ingredient in nearly all astrophysical and cosmological simulations. Choosing an appropriate discretization scheme is a crucial part of the simulation, since it not only determines the direct memory cost of the model but also largely determines the computational cost and the achievable accuracy. In this paper, we show how an appropriate choice of directional discretization scheme as well as spatial model mesh can help alleviate the computational cost, while largely retaining the accuracy. First, we discuss the adaptive ray-tracing scheme implemented in our 3D radiative transfer Library Magritte, that adapts the rays to the spatial mesh and uses a hierarchical directional discretization based on HEALPix. Second, we demonstrate how the free and open-source Software Library Gmsh can be used to generate high quality meshes that can be easily tailored for Magritte. In particular, we show how the local element size distribution of the mesh can be used to optimise the sampling of both analytically and numerically defined models. Furthermore, we show that when using the output of hydrodynamics simulations as input for a radiative transfer simulation, the number of elements in the input model can often be reduced by an order of magnitude, without significant loss of accuracy in the radiation field. We demonstrate this for two models based on a hierarchical octree mesh resulting from adaptive mesh refinement (AMR), as well as two models based on smoothed-particle hydrodynamics (SPH) data.
-
magritte a modern Software Library for 3d radiative transfer i non lte atomic and molecular line modelling
Monthly Notices of the Royal Astronomical Society, 2020Co-Authors: Frederik De Ceuster, W Homan, Jeremy Yates, L Decin, P A Boyle, James HetheringtonAbstract:Radiative transfer is a key component in almost all astrophysical and cosmological simulations. We present Magritte: a modern open-source Software Library for 3D radiative transfer. It uses a deterministic ray-tracer and formal solver, i.e. it computes the radiation field by tracing rays through the model and solving the radiative transfer equation in its second-order form along a fixed set of rays originating from each point. Magritte can handle structured and unstructured input meshes, as well as smoothed-particle hydrodynamics (SPH) particle data. In this first paper, we describe the numerical implementation, semi-analytic tests and cross-code benchmarks for the non-LTE line radiative transfer module of Magritte. This module uses the radiative transfer solver to self-consistently determine the populations of the quantised energy levels of atoms and molecules using an accelerated Lambda iteration (ALI) scheme. We compare Magritte with the established radiative transfer solvers Ratran (1D) and Lime (3D) on the van Zadelhoff benchmark and present a first application to a simple Keplerian disc model. Comparing with Lime, we conclude that Magritte produces more accurate and more precise results, especially at high optical depth, and that it is faster.
P A Boyle - One of the best experts on this subject based on the ideXlab platform.
-
magritte a modern Software Library for 3d radiative transfer ii adaptive ray tracing mesh construction and reduction
Monthly Notices of the Royal Astronomical Society, 2020Co-Authors: Frederik De Ceuster, W Homan, Jeremy Yates, L Decin, J Bolte, Silke Maes, Jolien Malfait, P A BoyleAbstract:Radiative transfer is a notoriously difficult and computationally demanding problem. Yet, it is an indispensable ingredient in nearly all astrophysical and cosmological simulations. Choosing an appropriate discretization scheme is a crucial part of the simulation, since it not only determines the direct memory cost of the model but also largely determines the computational cost and the achievable accuracy. In this paper, we show how an appropriate choice of directional discretization scheme as well as spatial model mesh can help alleviate the computational cost, while largely retaining the accuracy. First, we discuss the adaptive ray-tracing scheme implemented in our 3D radiative transfer Library Magritte, that adapts the rays to the spatial mesh and uses a hierarchical directional discretization based on HEALPix. Second, we demonstrate how the free and open-source Software Library Gmsh can be used to generate high quality meshes that can be easily tailored for Magritte. In particular, we show how the local element size distribution of the mesh can be used to optimise the sampling of both analytically and numerically defined models. Furthermore, we show that when using the output of hydrodynamics simulations as input for a radiative transfer simulation, the number of elements in the input model can often be reduced by an order of magnitude, without significant loss of accuracy in the radiation field. We demonstrate this for two models based on a hierarchical octree mesh resulting from adaptive mesh refinement (AMR), as well as two models based on smoothed-particle hydrodynamics (SPH) data.
-
magritte a modern Software Library for 3d radiative transfer i non lte atomic and molecular line modelling
Monthly Notices of the Royal Astronomical Society, 2020Co-Authors: Frederik De Ceuster, W Homan, Jeremy Yates, L Decin, P A Boyle, James HetheringtonAbstract:Radiative transfer is a key component in almost all astrophysical and cosmological simulations. We present Magritte: a modern open-source Software Library for 3D radiative transfer. It uses a deterministic ray-tracer and formal solver, i.e. it computes the radiation field by tracing rays through the model and solving the radiative transfer equation in its second-order form along a fixed set of rays originating from each point. Magritte can handle structured and unstructured input meshes, as well as smoothed-particle hydrodynamics (SPH) particle data. In this first paper, we describe the numerical implementation, semi-analytic tests and cross-code benchmarks for the non-LTE line radiative transfer module of Magritte. This module uses the radiative transfer solver to self-consistently determine the populations of the quantised energy levels of atoms and molecules using an accelerated Lambda iteration (ALI) scheme. We compare Magritte with the established radiative transfer solvers Ratran (1D) and Lime (3D) on the van Zadelhoff benchmark and present a first application to a simple Keplerian disc model. Comparing with Lime, we conclude that Magritte produces more accurate and more precise results, especially at high optical depth, and that it is faster.
Debra J Richardson - One of the best experts on this subject based on the ideXlab platform.
-
Software Library usage pattern extraction using aSoftware model checker
International Journal of Computers and Applications, 2009Co-Authors: E Ye, Debra J RichardsonAbstract:AbstractThe need to manually specify temporal properties of Software systems is a major barrier to wider adoption of Software model checking. To address this problem, we propose to automatically extract Software Library usage patterns, i.e., one type of temporal specifications. Our approach uses a model checker to check a set of template-based pattern candidates against existing programs, and identifies valid patterns based on model checking results. We applied our approach to extract one valid pattern of the C standard Library from 500 C programs in Sourceforge.net using BLAST, and used the extracted pattern to detect an error in an open source project.
-
Software Library usage pattern extraction using a Software model checker
Automated Software Engineering, 2006Co-Authors: E Ye, Debra J RichardsonAbstract:The need to manually specify temporal properties of Software systems is a major barrier to wider adoption of Software model checking, because the specification of Software temporal properties is a difficult, time-consuming, and error-prone process. To address this problem, we propose to automatically extract Software Library usage patterns, which are one type of temporal specifications. Our approach uses a model checker to check a set of Software Library usage pattern candidates against existing programs using that Library, and identifies valid patterns based on model checking results. These valid patterns can help programmers learn about common Software Library usage. They can also be used to check new programs using the same Library. We applied our approach to C programs using the OpenSSL Library and the C standard Library, and extracted valid usage patterns using BLAST. We also successfully used the extracted valid usage patterns to detect an error in an open source project hosted by SourceForge.net.
-
ICSE - LtRules: an automated Software Library usage rule extraction tool
Proceeding of the 28th international conference on Software engineering - ICSE '06, 2006Co-Authors: Chang Liu, Debra J RichardsonAbstract:The need to manually specify temporal properties of Software systems is a major barrier to wider adoption of Software model checking, because the specification of Software temporal properties is a difficult, time-consuming, and error-prone process. To address this problem, we propose to automatically extract Software Library usage rules, which are one type of temporal specifications. Our approach uses a model checker to check a set of Software Library usage rule candidates against known good programs using that Library, and identifies valid rules based on model checking results. These valid rules can help programmers learn about common Software Library usage. They can also be used to check new programs using the same Library. We have implemented our approach in an Eclipse plug-in named LtRules, which can extract Software Library usage rules from C programs using BLAST as the underlying model checker.
-
ASE - Software Library Usage Pattern Extraction Using a Software Model Checker
21st IEEE ACM International Conference on Automated Software Engineering (ASE'06), 2006Co-Authors: Chang Liu, Debra J RichardsonAbstract:The need to manually specify temporal properties of Software systems is a major barrier to wider adoption of Software model checking, because the specification of Software temporal properties is a difficult, time-consuming, and error-prone process. To address this problem, we propose to automatically extract Software Library usage patterns, which are one type of temporal specifications. Our approach uses a model checker to check a set of Software Library usage pattern candidates against existing programs using that Library, and identifies valid patterns based on model checking results. These valid patterns can help programmers learn about common Software Library usage. They can also be used to check new programs using the same Library. We applied our approach to C programs using the OpenSSL Library and the C standard Library, and extracted valid usage patterns using BLAST. We also successfully used the extracted valid usage patterns to detect an error in an open source project hosted by SourceForge.net.
