Standard FORTRAN Research Articles

Prediction of the Non-Linear Rupture of a Section Under Compound Deviated Bending

Abstract Under stresses close to the ultimate stresses, a reinforced concrete section yields and cracks. The calculation in linear elasticity no longer makes it possible to evaluate the real deformations of the section. One is then led to make a study in nonlinear elasticity. The object of this work is the elaboration of a calculation method in nonlinear elasticity, allowing the simulation until the failure of reinforced concrete sections subjected to a compound deviated bending taking into account the real behavior laws (nonlinear) of the materials (steel and concrete). A computer program is developed following FORTRAN standards, and then confronted with the obtained experimental results on failure tests of sections subjected to deflected bending. The comparison between the numerical simulation and the experimental test/calculation shows the achievement of satisfactory results.

Smart: A program to automatically compute accelerations and variational equations

Modern astronomical potentials modelling galaxies or stellar systems can be rather involved, and deriving their first derivatives (accelerations) and second derivatives (variational equations) in order to compute orbits and their chaoticity may be a formidable task. We present here a fully automated routine, dubbed Smart, with which the accelerations and the variational equations of an arbitrary potential that has been written in the Fortran 77 language can be computed. Almost any Fortran 77 statement is admitted in the potential, and the output are standard Fortran 77 routines ready to use. We validate our algorithm with a set of potentials including time-dependent, velocity-dependent and very complex potentials that even involve auxiliary routines. We also describe with some detail a realistic seven-component Galactic potential, MilkyWayHydra, which yields very involved derivatives, thus being a good test bed for Smart.

Numerical simulation of fracture behaviour of the shot-earth 772

Earth building techniques have been around for thousands of years. Among them, it is worth mentioning: cut blocks, poured earth, superadobe, adobe, cob, rammed earth, compressed stabilised earth blocks, wattle and daub, shaped earth, and straw-clay. An innovative technique among the earth building ones, and named shot-earth technique, is the topic of the present paper. The technology employs a specific mixture of the shot-earth (named shot-earth 772) consisting of 7 parts of excavated soil, 7 parts of aggregates and 2 parts of cement (by volume): the mixture stream is projected at high velocity onto a surface, adding about 3% of water (by volume) at the spraying nozzle. The present research work deals with the numerical simulation of the fracture behaviour of the shot-earth 772. More precisely, an experimental campaign performed to compute the fracture toughness of the material is here numerically simulated. To such an aim, a homemade Finite Element numerical model, developed in standard Fortran language, is used to simulate both flexural and fracture tests on the shot-earth considered. In fact, such a model is able to properly consider. The material fracture process is described by means of a cohesive law, which is introduced within the cracked zone, whereas an elastic law is adopted for the un-cracked region of the material. Subsequently, the Modified Two-Parameter Model is used in order to compute the fracture toughness, from both the experimental fracture tests and the corresponding numerical simulations. Finally, the numerical results are compared with the experimental ones.

UnDiFi-2D: An unstructured discontinuity fitting code for 2D grids

UnDiFi-2D, an open source (free software) Unstructured-grid, Discontinuity Fitting code, is presented. The aim of UnDiFi-2D is to model gas-dynamic discontinuities in two-dimensional (2D) flows as if they were true discontinuities of null thickness that bound regions of the flow-field where a smooth solution to the governing PDEs exists. UnDiFi-2D therefore needs to be coupled with an unstructured CFD solver that is used to discretize the governing PDEs within the smooth regions of the flow-field. Two different, in-house developed, CFD solvers are also included in the current distribution.The main features of the UnDiFi-2D software can be summarized as follows:Programming languageUnDiFi-2D is written in standard Fortran 77/95; its design is highly modular in order to enhance simplicity of use, maintenance and allow coupling with virtually any existing CFD solver;Usability, maintenance and enhancement In order to improve the usability, maintenance and enhancement of the code also the documentation has been carefully taken into account. The git distributed versioning system has been adopted to facilitate collaborative maintenance and code development;CopyrightsUnDiFi-2D is a free software that anyone can use, copy, distribute, change and improve under the GNU Public License version 3.The present paper is a manifesto of the first public release of the UnDiFi-2D code. It describes the currently implemented features, which are the result of more than a decade of still ongoing CFD developments. This work is focused on the computational techniques adopted and a detailed description of the main characteristics is reported. UnDiFi-2D capabilities are demonstrated by means of examples test cases. The design of the code allows to easily include existing CFD codes and is aimed at ease code reuse and readability. Program summaryProgram title: UnDiFi-2DCPC Library link to program files:https://doi.org/10.17632/5hwssmc2mx.1Licensing provisions: GNU General Public License, version 3Programming language: Fortran; developed and tested with Intel Fortran Compiler v. 18.0.3 and GNU gfortran.External routines: The code depends on several libraries and third-party packages which are detailed in the corpus of the text.Nature of problem: Numerical computation of flows with discontinuities.Solution method: Shock-fitting technique.Additional comments including restrictions and unusual features:•At present, UnDiFi-2D is validated for inviscid steady and unsteady two-dimensional flows without changes in the number of discontinuity lines and interaction points.•UnDiFi-2D implements a shock-fitting algorithm and can be coupled with unstructured cell-vertex solvers, with an Arbitrary Lagrangian-Eulerian (ALE) formulation.•UnDiFi-2D project adopts git [1], a free and open source distributed version control system. A public repository dedicated to UnDiFi-2D project [2] has been created on github [3], a web-based hosting service for software development projects using git versioning system. Finally, a comprehensive documentation is provided in the form of user manual developed in Pandoc [4].

An <i>N</i>-dimensional Fortran interpolation programme (NterGeo.v2020a) for geophysics sciences – application to a back-trajectory programme (Backplumes.v2020r1) using CHIMERE or WRF outputs

Abstract. An interpolation programme coded in Fortran for irregular N-dimensional cases is presented and freely available. The need for interpolation procedures over irregular meshes or matrixes with interdependent input data dimensions is frequent in geophysical models. Also, these models often embed look-up tables of physics or chemistry modules. Fortran is a fast and powerful language and is highly portable. It is easy to interface models written in Fortran with each other. Our programme does not need any libraries; it is written in standard Fortran and tested with two usual compilers. The programme is fast and competitive compared to current Python libraries. A normalization option parameter is provided when considering different types of units on each dimension. Some tests and examples are provided and available in the code package. Moreover, a geophysical application embedding this interpolation programme is provided and discussed; it consists in determining back trajectories using chemistry-transport or mesoscale meteorological model outputs, respectively, from the widely used CHIMERE and Weather Research and Forecasting (WRF) models.

Compiler Support for the Fortran 2008 and 2018 Standards

This document looks at compiler support for the most recent Fortran standards. It is a successor to a previous document that looked at support for earlier standards. As most actively developed compilers now fully support the Fortran 2003 standard (with some minor exceptions) our starting point is the Fortran 2008 standard.

Remark on Algorithm 539

We propose a set of new Fortran reference implementations, based on an algorithm proposed by Kahan, for the Level 1 BLAS routines *NRM2 that compute the Euclidean norm of a real or complex input vector. The principal advantage of these routines over the current offerings is that, rather than losing accuracy as the length of the vector increases, they generate results that are accurate to almost machine precision for vectors of length N < N max where N max depends upon the precision of the floating point arithmetic being used. In addition, we make use of intrinsic modules, introduced in the latest Fortran standards, to detect occurrences of non-finite numbers in the input data and return suitable values as well as setting IEEE floating point status flags as appropriate. A set of C interface routines is also provided to allow simple, portable access to the new routines. To improve execution speed, we advocate a hybrid algorithm; a simple loop is used first and, only if IEEE floating point exception flags signal, do we fall back on Kahan’s algorithm. Since most input vectors are “easy,” i.e., they do not require the sophistication of Kahan’s algorithm, the simple loop improves performance while the use of compensated summation ensures high accuracy. We also report on a comprehensive suite of test problems that has been developed to test both our new implementation and existing codes for both accuracy and the appropriate settings of the IEEE arithmetic status flags.

PHAST: Protein-like heteropolymer analysis by statistical thermodynamics

PHAST is a software package written in standard Fortran, with MPI and CUDA extensions, able to efficiently perform parallel multicanonical Monte Carlo simulations of single or multiple heteropolymeric chains, as coarse-grained models for proteins. The outcome data can be straightforwardly analyzed within its microcanonical Statistical Thermodynamics module, which allows for computing the entropy, caloric curve, specific heat and free energies. As a case study, we investigate the aggregation of heteropolymers bioinspired on Aβ25−33 fragments and their cross-seeding with IAPP20−29 isoforms. Excellent parallel scaling is observed, even under numerically difficult first-order like phase transitions, which are properly described by the built-in fully reconfigurable force fields. Still, the package is free and open source, this shall motivate users to readily adapt it to specific purposes.Program summaryProgram Title: PHASTProgram Files doi:http://dx.doi.org/10.17632/ggds2grzw9.1Licensing provisions: GNU GPL version 3Programming language: FORTRAN 90, MPICH 3.0.4, CUDA 8.0Nature of the problem: Nowadays powerful multicore processors (CPUs) and Graphical Processing Units (GPUs) became much popular and cost-effective, so enabling thermostatistical studies of complex molecular systems to be performed even in personal computers. PHAST provides not only an easily-reconfigurable parallel program for Monte Carlo simulations of linear heteropolymers, as coarse-grained models of proteins, but also permits the automatized microcanonical thermodynamic analysis of those systems.Solution method: PHAST has three main modules for complementary tasks as: to map any .pdb file-sequence to its inner lexicon by using a configurable hydrophobic scale, while the main simulational module performs parallel Monte Carlo simulations in the multicanonical (MUCA) ensemble and, the analysis module which extracts microcanonical observables from MUCA weights.External routines/libraries: cuRAND (CUDA), Grace-5.1.22 or higher.

Three Dimensional Finite Element Program for Determination of Cure Level in Thick Rubber Part

The vulcanization or curing process begins in a heated mould to convert viscous uncured rubber materials into functional elastic ones. As the mechanical properties and service performances of the final products are greatly affected by the state of cure or cure level of rubbers, thus it is very crucial to use suitable time, pressure and temperature for the curing process to ensure that the desired quality of the final products are obtained. A computer program “RACE-CURE” written in standard FORTRAN code has been developed by our research team for the analysis of curing process of large rubber parts. The program is developed based on the incremental finite element formulation for three dimensional nonlinear transient heat transfer analysis coupled with cure kinetics. The RACE-CURE is tested for a test problem of curing of a large rubber block and results are compared to another two programs: ANSYS Polyflow v.14 and CFEM, a MATLAB© FEM program with capability to add curing kinetics, independently developed at our research group.

Quantity Correctness in Fortran Programs

The ISO/IEC Fortran standards working group states that the third most detectable type of error in scientific software is “incorrect use of units of measurement” and has developed a draft specification for incorporating unit-checking into Fortran compilers. This article shows that unit-checking is insufficient to detect all quantity errors, and that kind-of-quantity also needs to be verified. A suggested syntax and program for a Fortran source-code preprocessor are given.

Comparing Coarray Fortran (CAF) with MPI for several structured mesh PDE applications

Language-based approaches to parallelism have been incorporated into the Fortran standard. These Fortran extensions go under the name of Coarray Fortran (CAF) and full-featured compilers that support CAF have become available from Cray and Intel; the GNU implementation is expected in 2015. CAF combines elegance of expression with simplicity of implementation to yield an efficient parallel programming language. Elegance of expression results in very compact parallel code. The existence of a standard helps with portability and maintainability. CAF was designed to excel at one-sided communication and similar functions that support one-sided communication are also available in the recent MPI-3 standard. One-sided communication is expected to be very valuable for structured mesh applications involving partial differential equations, amongst other possible applications. This paper focuses on a comparison of CAF and MPI for a few very useful applications areas that are routinely used for solving partial differential equations on structured meshes. The three specific areas are Fast Fourier Techniques, Computational Fluid Dynamics, and Multigrid Methods.For each of those applications areas, we have developed optimized CAF code and optimized MPI code that is based on the one-sided messaging capabilities of MPI-3. Weak scalability studies that compare CAF and MPI-3 are presented on up to 65,536 processors. Both paradigms scale well, showing that they are well-suited for Petascale-class applications. Some of the applications shown (like Fast Fourier Techniques and Computational Fluid Dynamics) require large, coarse-grained messaging. Such applications emphasize high bandwidth. Our other application (Multigrid Methods) uses pointwise smoothers which require a large amount of fine-grained messaging. In such applications, a premium is placed on low latency. Our studies show that both CAF and MPI-3 offer the twin advantages of high bandwidth and low latency for messages of all sizes. Even for large numbers of processors, CAF either draws level with MPI-3 or shows a slight advantage over MPI-3. Both CAF and MPI-3 are shown to provide substantial advantages over MPI-2.In addition to the weak scalability studies, we also catalogue some of the best-usage strategies that we have found for our successful implementations of one-sided messaging in CAF and MPI-3. We show that CAF code is of course much easier to write and maintain, and the simpler syntax makes the parallelism easier to understand.

Fortran 2008 coarrays

Coarrays are a Fortran 2008 standard feature intended for SIMD type parallel programming. The runtime environment starts a number of identical executable images of the coarray program, on multiple processors, which could be actual physical processors or threads. Each image has a unique number and its private address space. Ordinary variables are private to an image. Coarray variables are available for read/write access from any other image. Coarray communications are of "single sided" type, i.e. a remote call from imageA to image B does not need to be accompanied by a corresponding call in image B. This feature makes coarray programming a lot simpler than MPI. The standard provides synchronisation intrinsics to help avoid race conditions or deadlocks. Any ordinary variable can be made into a coarray - scalars, arrays, intrinsic or derived data types, pointers, allocatables are all allowed. Coarrays can be declared in, and passed to, procedures. Coarrays are thus very flexible and can be used for a number of purposes. For example a collection of coarrays from all or some images can be thought of as a large single array. This is precisely the inverse of the model partitioning logic, typical in MPI programs. A coarray program can exploit functional parallelism too, by delegating dis- tinct tasks to separate images or teams of images. Coarray collectives are expected to become a part of the next version of the Fortran standard. A major unresolved problem of coarray programming is the lack of standard parallel I/O facility in Fortran. In this paper several simple complete coarray programs are shown and compared to alternative parallel technologies - OpenMP, MPI and Fortran 2008 intrinsic "do concurrent". Inter image communication patterns and data transfer are illustrated. An example of a materials microstructure simulation coarray program scaled up to 32k cores is shown. Problems with coarray I/O at this scale are highlighted and addressed with the use of MPI-I/O. A hybrid MPI/coarray programming is discussed and illustrated with a finite element/cellular automata (CAFÉ) multi-scale model. The paper completes with a description of the new coarray language features, expected in the 2015 Fortran standard, and with a brief list of coarray resources

Statements, data types and intrinsic procedures in the Fortran standards (1966-2008)

This paper contains the tables of statements, data types and intrinsic procedures in consecutive Fortran standards: from Fortran 66 up to Fortran 2008.

Statements, data types and intrinsic procedures in the Fortran standards (1966-2008)

This paper contains the tables of statements, data types and intrinsic procedures in consecutive Fortran standards: from Fortran 66 up to Fortran 2008.

Computer program for the sensitivity calculation of a CR-39 detector in a diffusion chamber for radon measurements

Computer software for calculation of the sensitivity of a CR-39 detector closed in a diffusion chamber to radon is described in this work. The software consists of two programs, both written in the standard Fortran 90 programming language. The physical background and a numerical example are given. Presented software is intended for numerous researches in radon measurement community. Previously published computer programs TRACK_TEST.F90 and TRACK_VISION.F90 [D. Nikezic and K. N. Yu, Comput. Phys. Commun. 174, 160 (2006); D. Nikezic and K. N. Yu, Comput. Phys. Commun. 178, 591 (2008)] are used here as subroutines to calculate the track parameters and to determine whether the track is visible or not, based on the incident angle, impact energy, etching conditions, gray level, and visibility criterion. The results obtained by the software, using five different V functions, were compared with the experimental data found in the literature. Application of two functions in this software reproduced experimental data very well, while other three gave lower sensitivity than experiment.

Отображение на кластеры с графическими процессорами DVMH-программ с регулярными зависимостями по данным.

In the 2011 year DVMH programming model for new heterogeneous and hybrid supercomputer systems (or DVM for Heterogeneous systems) was introduced in the Keldysh Institute for Applied Mathematics of RAS. The developed high-level programming languages were based on standard Fortran and C programming languages, but extended with the directives for mapping the program onto a parallel computer. The directives are represented as special comments (or pragmas). The paper describes problems and methods for mapping loops, which have dependencies to the GPU. Efficiency of the developed Fortran DVMH parallel programs with regular dependencies is demonstrated.

Использование языка FORTRAN DVMH для решения задач гидродинамики на высокопроизводительных гибридных вычислительных системах.

In the 2011 year DVMH programming model for new heterogeneous and hybrid supercomputer systems (or DVM for Heterogeneous systems) was introduced in the Keldysh Institute for Applied Mathematics of RAS. The developed high-level programming languages were based on standard Fortran and C programming languages, but extended with the directives for mapping the program onto a parallel computer. The directives are represented as special comments (or pragmas). The paper includes analysis of the efficiency of the developed programs for solving the hydrodynamics problems «Cavity» and «Container». The calculation results are gained by using several thousand CPU cores and gained by using morethan 1200 GPU accelerators are presented.

Program Fullerene: A software package for constructing and analyzing structures of regular fullerenes

Fullerene (Version 4.4) is a general purpose open-source program that can generate any fullerene isomer, perform topological and graph theoretical analysis, as well as calculate a number of physical and chemical properties. The program creates symmetric planar drawings of the fullerene graph and generates accurate molecular 3D geometries by way of force-field optimization, serving as a good starting point for further quantum theoretical treatments. It includes a number of fullerene-to-fullerene transformations, such as Goldberg-Coxeter transforms, Stone-Wales transforms, Endo-Kroto, Yoshida-Fowler, and Brinkmann-Fowler vertex insertions. The program is written in standard Fortran and C++ and can easily be installed in a Linux or UNIX environment.

The Ratip program for relativistic calculations of atomic transition, ionization and recombination properties

The Ratip program for relativistic calculations of atomic transition, ionization and recombination properties

QMENF-G: A computer package for quasi-mono-energetic neutron filters

A computer package QMENF-G was developed in a general form to calculate the optimum amounts and components of quasi-mono-energetic neutron filters and their transmitted spectra in order to meet requirements for different applications in various fields. This code is a complete system to assist the user with input preparation, running calculations and analysis of output results. It is written in standard FORTRAN that runs on any personal computer using windows operating system. As a test case, the components and amounts of elements for producing a neutron filter at ∼3.8 keV was calculated using QMENF-G code. It was found that 54Fe, 80Se or 90Zr, can be used as the main components of such filter. However, its transmission, resolution and purity were found to depend upon the accompanying components and their amounts.