scholarly journals The Transition and Adoption to Modern Programming Concepts for Scientific Computing in Fortran

2007 ◽  
Vol 15 (1) ◽  
pp. 27-44 ◽  
Author(s):  
Charles D. Norton ◽  
Viktor K. Decyk ◽  
Boleslaw K. Szymanski ◽  
Henry Gardner
Keyword(s):  
Design Patterns ◽  
Adaptive Mesh Refinement ◽  
Large Scale ◽  
Object Oriented ◽  
Adaptive Mesh ◽  
Particle Simulation ◽  
Programming Techniques ◽  
Early Exploration ◽  
The Impact ◽  
Development Applications

This paper describes our experiences in the early exploration of modern concepts introduced in Fortran90 for large-scale scientific programming. We review our early work in expressing object-oriented concepts based on the new Fortran90 constructs – foreign to most programmers at the time – our experimental work in applying them to various applications, the impact on the WG5/J3 standards committees to consider formalizing object-oriented constructs for later versions of Fortran, and work in exploring how other modern programming techniques such as Design Patterns can and have impacted our software development. Applications will be drawn from plasma particle simulation and finite element adaptive mesh refinement for solid earth crustal deformation modeling.

Development of an Object-Oriented Program With Adaptive Mesh Refinement for Heat Transfer Simulations

2007 ◽  
Author(s):  
Jianhu Nie ◽  
David A. Hopkins ◽  
Yitung Chen ◽  
Hsuan-Tsung Hsieh
Keyword(s):  
Heat Transfer ◽  
Adaptive Mesh Refinement ◽  
Large Scale ◽  
Mesh Refinement ◽  
Object Oriented ◽  
Adaptive Mesh ◽  
Time Cost ◽  
Test Bed ◽  
Element Analysis ◽  
Cpu Time

A 2D/3D object-oriented program with h-type adaptive mesh refinement method is developed for finite element analysis of the multi-physics applications including heat transfer. A framework with some basic classes that enable the code to be built accordingly to the type of problem to be solved is proposed. The program consists of different modules and classes, which ease code development for large-scale complex systems, code extension and program maintenance. The developed program can be used as a “test-bed” program for testing new analysis techniques and algorithms with high extensibility and flexibility. The overall mesh refinement causes the CPU time cost to greatly increase as the mesh is refined. However, the CPU time cost does not increase very much with the increase of the level of h-adaptive mesh refinement. The CPU time cost can be saved by up to 90%, especially for the simulated system with a large number of elements and nodes.

JAVASCRIPT ASYNCHRONOUS PROGRAMMING

2019 ◽  
Vol 128 (2B) ◽  
pp. 5-16
Author(s):  
Tran Thanh Luong ◽  
Le My Canh
Keyword(s):  
Design Patterns ◽  
Source Code ◽  
Object Oriented ◽  
Exception Handling ◽  
Code Smells ◽  
Asynchronous Programming ◽  
Event Driven ◽  
Programming Patterns ◽  
The Impact

JavaScript has become more and more popular in recent years because its wealthy features as being dynamic, interpreted and object-oriented with first-class functions. Furthermore, JavaScript is designed with event-driven and I/O non-blocking model that boosts the performance of overall application especially in the case of Node.js. To take advantage of these characteristics, many design patterns that implement asynchronous programming for JavaScript were proposed. However, choosing a right pattern and implementing a good asynchronous source code is a challenge and thus easily lead into less robust application and low quality source code. Extended from our previous works on exception handling code smells in JavaScript and exception handling code smells in JavaScript asynchronous programming with promise, this research aims at studying the impact of three JavaScript asynchronous programming patterns on quality of source code and application.

scholarly journals EDGE: a new approach to suppressing numerical diffusion in adaptive mesh simulations of galaxy formation

2020 ◽  
Vol 501 (2) ◽  
pp. 1755-1765
Author(s):  
Andrew Pontzen ◽  
Martin P Rey ◽  
Corentin Cadiou ◽  
Oscar Agertz ◽  
Romain Teyssier ◽  
...  
Keyword(s):  
Star Formation ◽  
Galaxy Formation ◽  
Adaptive Mesh Refinement ◽  
Large Scale ◽  
Initial Conditions ◽  
Dwarf Galaxy ◽  
High Redshift ◽  
Morphological Structure ◽  
Adaptive Mesh ◽  
Numerical Diffusion

ABSTRACT We introduce a new method to mitigate numerical diffusion in adaptive mesh refinement (AMR) simulations of cosmological galaxy formation, and study its impact on a simulated dwarf galaxy as part of the ‘EDGE’ project. The target galaxy has a maximum circular velocity of $21\, \mathrm{km}\, \mathrm{s}^{-1}$ but evolves in a region that is moving at up to $90\, \mathrm{km}\, \mathrm{s}^{-1}$ relative to the hydrodynamic grid. In the absence of any mitigation, diffusion softens the filaments feeding our galaxy. As a result, gas is unphysically held in the circumgalactic medium around the galaxy for $320\, \mathrm{Myr}$, delaying the onset of star formation until cooling and collapse eventually triggers an initial starburst at z = 9. Using genetic modification, we produce ‘velocity-zeroed’ initial conditions in which the grid-relative streaming is strongly suppressed; by design, the change does not significantly modify the large-scale structure or dark matter accretion history. The resulting simulation recovers a more physical, gradual onset of star formation starting at z = 17. While the final stellar masses are nearly consistent ($4.8 \times 10^6\, \mathrm{M}_{\odot }$ and $4.4\times 10^6\, \mathrm{M}_{\odot }$ for unmodified and velocity-zeroed, respectively), the dynamical and morphological structure of the z = 0 dwarf galaxies are markedly different due to the contrasting histories. Our approach to diffusion suppression is suitable for any AMR zoom cosmological galaxy formation simulations, and is especially recommended for those of small galaxies at high redshift.

scholarly journals The impact of AGN feedback on the 1D power spectra from the Ly α forest using the Horizon-AGN suite of simulations

2020 ◽  
Vol 495 (2) ◽  
pp. 1825-1840 ◽  
Author(s):  
Solène Chabanier ◽  
Frédéric Bournaud ◽  
Yohan Dubois ◽  
Nathalie Palanque-Delabrouille ◽  
Christophe Yèche ◽  
...  
Keyword(s):  
Galaxy Evolution ◽  
Adaptive Mesh Refinement ◽  
Power Spectra ◽  
Adaptive Mesh ◽  
Processing Stage ◽  
Galactic Winds ◽  
Upper Limits ◽  
Feeding Parameters ◽  
Future Work ◽  
The Impact

ABSTRACT The Lyman-α forest is a powerful probe for cosmology, but it is also strongly impacted by galaxy evolution and baryonic processes such as active galactic nucleus (AGN) feedback, which can redistribute mass and energy on large scales. We constrain the signatures of AGN feedback on the 1D power spectrum of the Lyman-α forest using a series of eight hydro-cosmological simulations performed with the adaptive mesh refinement code ramses. This series starts from the Horizon-AGN simulation and varies the subgrid parameters for AGN feeding, feedback, and stochasticity. These simulations cover the whole plausible range of feedback and feeding parameters according to the resulting galaxy properties. AGNs globally suppress the Lyman-α power at all scales. On large scales, the energy injection and ionization dominate over the supply of gas mass from AGN-driven galactic winds, thus suppressing power. On small scales, faster cooling of denser gas mitigates the suppression. This effect increases with decreasing redshift. We provide lower and upper limits of this signature at nine redshifts between z = 4.25 and 2.0, making it possible to account for it at post-processing stage in future work given that running simulations without AGN feedback can save considerable amounts of computing resources. Ignoring AGN feedback in cosmological inference analyses leads to strong biases with 2 per cent shift on σ8 and 1 per cent shift on ns, which represents twice the standards deviation of the current constraints on ns.

CFD simulations of tsunamis from large scale propagation up to local coastal impacts

2020 ◽  
Author(s):  
Richard Marcer ◽  
Camille Journeau ◽  
Kévin Pons
Keyword(s):  
Adaptive Mesh Refinement ◽  
Large Scale ◽  
Adaptive Mesh ◽  
Navier Stokes ◽  
Water Volume ◽  
Tsunami Propagation ◽  
Tsunami Modelling ◽  
Tsunami Waves ◽  
In Situ Data ◽  
Run Up

<p>This work has been performed within the framework of the TANDEM project (Tsunamis in northern AtlaNtic: Definition of Effects by Modelling) which is dedicated to the appraisal of coastal effects due to tsunami waves on the French coastlines. One of the identified objectives of TANDEM consisted in designing, adapting and validating numerical codes for tsunami hazard assessment, addressing the various stages of a tsunami event: generation, propagation, run-up and coastal inundation.</p><p>PRINCIPIA has been working on the development and qualification of two in-house CFD software’s: a 2D Saint-Venant model (often called NLSW for Non-Linear Shallow Water) using an Adaptive Mesh Refinement (AMR) for simulation of large scale tsunami propagation from the source up to coastal scale, and a 3D Navier-Stokes model dedicated to tsunami coastal impact modelling.</p><p>An overview of the results obtained with both codes aiming at being applicable to tsunami modelling, is presented. The validation process has been done on several academic test cases having experimental data for comparisons, as the breaking of a solitary wave on a reef, the generation of a long wave induced by a vertical bloc (massive cliffs, ice bodies) falling down an underlying water volume, the tsunami generation due to a submarine landslide and the tsunami impact on a coastal city.</p><p>A real case simulation is concerned as well, the devastating 2011 Tohoku event which is compared with in-situ data.</p><p>The work was supported by the Tandem project in the frame of French PIA grant ANR-11-RSNR-00023.</p>

Computational Fluid-Structure Interaction of DGB Parachutes in Compressible Fluid Flow

2010 ◽  
Author(s):  
Carlos Pantano-Rubino ◽  
Kostas Karagiozis ◽  
Ramji Kamakoti ◽  
Fehmi Cirak
Keyword(s):  
Adaptive Mesh Refinement ◽  
Compressible Flows ◽  
Large Scale ◽  
Structural Model ◽  
Fluid Model ◽  
Fluid Structure Interaction ◽  
Adaptive Mesh ◽  
Turbulent Wake ◽  
Fluid Structure ◽  
Structure Interaction

This paper describes large-scale simulations of compressible flows over a supersonic disk-gap-band parachute system. An adaptive mesh refinement method is used to resolve the coupled fluid-structure model. The fluid model employs large-eddy simulation to describe the turbulent wakes appearing upstream and downstream of the parachute canopy and the structural model employed a thin-shell finite element solver that allows large canopy deformations by using subdivision finite elements. The fluid-structure interaction is described by a variant of the Ghost-Fluid method. The simulation was carried out at Mach number 1.96 where strong nonlinear coupling between the system of bow shocks, turbulent wake and canopy is observed. It was found that the canopy oscillations were characterized by a breathing type motion due to the strong interaction of the turbulent wake and bow shock upstream of the flexible canopy.

scholarly journals Three-dimensional Visualization of Cosmological and Galaxy Formation Simulations

2010 ◽  
Vol 6 (S277) ◽  
pp. 263-266
Author(s):  
Bruno Thooris ◽  
Daniel Pomarède
Keyword(s):  
Galaxy Formation ◽  
Adaptive Mesh Refinement ◽  
Large Scale ◽  
Multiple Scales ◽  
Three Dimensional ◽  
Adaptive Mesh ◽  
Ray Casting ◽  
Parallel Simulations ◽  
The Galaxy ◽  
Isosurface Reconstruction

AbstractOur understanding of the structuring of the Universe from large-scale cosmological structures down to the formation of galaxies now largely benefits from numerical simulations. The RAMSES code, relying on the Adaptive Mesh Refinement technique, is used to perform massively parallel simulations at multiple scales. The interactive, immersive, three-dimensional visualization of such complex simulations is a challenge that is addressed using the SDvision software package. Several rendering techniques are available, including ray-casting and isosurface reconstruction, to explore the simulated volumes at various resolution levels and construct temporal sequences. These techniques are illustrated in the context of different classes of simulations. We first report on the visualization of the HORIZON Galaxy Formation Simulation at MareNostrum, a cosmological simulation with detailed physics at work in the galaxy formation process. We then carry on in the context of an intermediate zoom simulation leading to the formation of a Milky-Way like galaxy. Finally, we present a variety of simulations of interacting galaxies, including a case-study of the Antennae Galaxies interaction.

An adaptive mesh refinement solver for large-scale simulation of biological flows

2010 ◽  
Vol 26 (1) ◽  
pp. 86-100 ◽  
Author(s):  
Lorenzo Botti ◽  
Marina Piccinelli ◽  
Bogdan Ene-Iordache ◽  
Andrea Remuzzi ◽  
Luca Antiga
Keyword(s):  
Adaptive Mesh Refinement ◽  
Large Scale ◽  
Mesh Refinement ◽  
Adaptive Mesh ◽  
Large Scale Simulation ◽  
Biological Flows
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