scholarly journals Making legacy Fortran code type safe through automated program transformation

2021 ◽  
Author(s):  
Wim Vanderbauwhede
Keyword(s):  
Side Effect ◽  
Program Transformation ◽  
The Novel ◽  
Formal Approach ◽  
Type Checking ◽  
Type Safety ◽  
Fortran Code ◽  
Fortran 90 ◽  
Code Type ◽  
Fortran 77

AbstractFortran is still widely used in scientific computing, and a very large corpus of legacy as well as new code is written in FORTRAN 77. In general this code is not type safe, so that incorrect programs can compile without errors. In this paper, we present a formal approach to ensure type safety of legacy Fortran code through automated program transformation. The objective of this work is to reduce programming errors by guaranteeing type safety. We present the first rigorous analysis of the type safety of FORTRAN 77 and the novel program transformation and type checking algorithms required to convert FORTRAN 77 subroutines and functions into pure, side-effect free subroutines and functions in Fortran 90. We have implemented these algorithms in a source-to-source compiler which type checks and automatically transforms the legacy code. We show that the resulting code is type safe and that the pure, side-effect free and referentially transparent subroutines can readily be offloaded to accelerators.

scholarly journals Photometric modelling of starspots -- II. The FORTRAN code SPOTPIC

2000 ◽  
Vol 314 (3) ◽  
pp. 489-497 ◽  
Author(s):  
P. J. Amado ◽  
J. G. Doyle ◽  
P. B. Byrne
Keyword(s):  
Fortran Code

FORTRAN Code for 1986 AASHTO Guide Equations

1990 ◽  
Vol 116 (3) ◽  
pp. 396-403
Author(s):  
William W. Crockford
Keyword(s):  
Fortran Code

scholarly journals Two-loop $$ \mathcal{O} $$((αt + αλ + ακ)2) corrections to the Higgs boson masses in the CP-violating NMSSM

2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
Thi Nhung Dao ◽  
Martin Gabelmann ◽  
Margarete Mühlleitner ◽  
Heidi Rzehak
Keyword(s):  
Higgs Boson ◽  
Higgs Mass ◽  
Goldstone Boson ◽  
Higgs Sector ◽  
Momentum Dependence ◽  
Loop Order ◽  
Fortran Code ◽  
Higher Order Corrections ◽  
Infrared Divergences ◽  
The Impact

Abstract We present our computation of the $$ \mathcal{O} $$ O ((αt + αλ + ακ)2) two-loop corrections to the Higgs boson masses of the CP-violating Next-to-Minimal Supersymmetric Standard Model (NMSSM) using the Feynman-diagrammatic approach in the gaugeless limit at vanishing external momentum. We choose a mixed $$ \overline{\mathrm{DR}} $$ DR ¯ -on-shell (OS) renormalisation scheme for the Higgs sector and apply both $$ \overline{\mathrm{DR}} $$ DR ¯ and OS renormalisation in the top/stop sector. For the treatment of the infrared divergences we apply and compare three different regularisation methods: the introduction of a regulator mass, the application of a small momentum expansion, and the inclusion of the full momentum dependence. Our new corrections have been implemented in the Fortran code NMSSMCALC that computes the Higgs mass spectrum of the CP-conserving and CP-violating NMSSM as well as the Higgs boson decays including the state-of-the-art higher-order corrections. Our numerical analysis shows that the newly computed corrections increase with rising λ and κ, remaining overall below about 3% compared to our previously computed $$ \mathcal{O} $$ O (αt(αt + αs)) corrections, in the region compatible with perturbativity below the GUT scale. The renormalisation scheme and scale dependence is of typical two-loop order. The impact of the CP-violating phases in the new corrections is small. We furthermore show that the Goldstone Boson Catastrophe due to the infrared divergences can be treated in a numerically efficient way by introducing a regulator mass that approximates the momentum-dependent results best for squared mass values in the permille range of the squared renormalisation scale. Our results mark another step forward in the program of increasing the precision in the NMSSM Higgs boson observables.

Numerical Simulation of Cavitating Flow Around a Hydrofoil

2014 ◽  
Author(s):  
Tan Dung Tran ◽  
Bernd Nennemann ◽  
Thi Cong Vu ◽  
François Guibault
Keyword(s):  
Turbulence Models ◽  
Cavitating Flow ◽  
Navier Stokes ◽  
Naval Academy ◽  
Cavitating Flows ◽  
Compressibility Effect ◽  
Hybrid Meshes ◽  
Fortran Code ◽  
Cavitation Tunnel ◽  
Prediction Capability

The objective of this paper is to evaluate the applicability of different cavitation models and determine appropriate numerical parameters for cavitating flows around a hydrofoil. The simulations are performed for a NACA 66 foil at 6 degrees angle of attack, Reynolds number of 750 000 and for a cavitation number of 1.49 corresponding to the partial sheet cavitating regime. The incompressible, multiphase Reynolds-averaged Navier-Stokes (RANS) equations are solved by the CFD solver CFX with Kubota and Merkle cavitation models. As part of the work, the Merkle model is implemented into CFX by User Fortran code because this model has shown good cavitation prediction capability according to the literature. The effects of the k-ε and SST turbulence models on the cavitating flow dynamics are compared. Also, an investigation on structured and hybrid meshes with different mesh sizes and concentrations is carried out in order to better understand the mesh influence for this cavitation simulation. The local compressibility effect is considered by correcting the turbulent eddy viscosity inside the mixture vapor/liquid zones. The numerical results are validated by experiments conducted in a cavitation tunnel at the French Naval Academy.

A Window Based Graphical User Interface for a Supersonic Combustion Fortran Code

1992 ◽  
Author(s):  
T. Gary Yip ◽  
Ajay R. Patel
Keyword(s):  
Real Time ◽  
Input Sequence ◽  
Supersonic Combustion ◽  
Input File ◽  
Input Interface ◽  
Wide Acceptance ◽  
Fortran Code ◽  
Questions And Answers ◽  
Application Programs ◽  
Made In

Abstract Fortran has been used widely in number crunching applications. In recent years, as the size of application programs increases significantly, users begin to demand interactive capability so that they can interface with the applications in real time in a more flexible and convenient manner. In spite of the wide acceptance by engineers in various fields in the seventies and eighties, Fortran currently does not offer these features. INPUT/OUTPUT are structured rigidly by the order of the READ and WRITE statements in the application programs. The situation would get even worse when the program requires a large number of inputs from the user. A user can use a large input file in which the data must be in a fixed format and no comment statements are allowed. An alternative is to write a real time input interface with requests for inputs displayed on the screen. This leads to a long list of questions and answers scrolling up the screen. When a mistake is made in answering any one of the questions, the input sequence has to be restarted at the beginning of the program again.

GPU acceleration of the FESOM-2 ocean and sea-ice model

2021 ◽  
Author(s):  
Gijs van den Oord ◽  
Alessio Sclocco ◽  
Georges-Emmanuel Moulard ◽  
David Guibert ◽  
Dmitry Sidorenko ◽  
...  
Keyword(s):  
Sea Ice ◽  
Ocean Circulation ◽  
Gpu Acceleration ◽  
Dominant Factor ◽  
Tracer Transport ◽  
Fortran Code ◽  
Mesh Resolution ◽  
Engineering Effort ◽  
Access Patterns ◽  
Ice Model

<p>FESOM-2 is a finite volume ocean circulation and sea ice model developed by the Alfred Wegener Institute (AWI). It solves the primitive equations using the hydrostatic and Bousinessq approximations on an unstructured grid, allowing seamless mesh resolution increase towards eddy-resolving scales in regions of high variability or along coast lines. FESOM-2 is a highly optimized MPI-parallel Fortran code that displays excellent scaling to tens of thousands of cores. In the context of ESiWACE-2 services, we have explored the benefits of GPU acceleration of FESOM-2 in a six-month engineering effort. We have determined the flux-corrected tracer transport, and in particular the advection of temperature and salinity, to be a dominant factor in the application profile and we have ported this routine to GPUs using both OpenACC and CUDA-C. We conclude that the memory access patterns in FESOM-2 are suitable to map onto GPU accelerators and that both strategies are viable options, giving significant speedups for tracer advection in high-resolution mesh configurations. We have benchmarked the ported application on Nvidia Kepler, Volta and Ampere architectures and observe that our tuned kernels can approach the peak memory bandwidth, and we also see that OpenACC offers a competitive performance with less development and maintenance effort. We conclude that an expansion of the OpenACC directives is the most promising road to utilize upcoming GPU-equipped exascale machines for FESOM-2.</p>

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