EAS3
Encyclopedia
EAS3 is a software toolkit for reading and writing structured binary data with geometry information and for postprocessing of these data. It is meant to exchange floating-point data according to IEEE standard between different computers, to modify them or to convert them into other file formats. It can be used for all kinds of structured data sets. It is mainly used in the field of direct numerical simulation
s.
and C
and runs on all POSIX
operating systems. The libraries include different numerical algorithms and subroutines for reading and writing files in the binary EAS3 file format. The read/write routines are provided in Fortran and C. Implemented numerical methods include, for example, Fast Fourier transform
, Thomas algorithm
and interpolation
routines. The libraries are also suitable for vector computers.
. The previous versions (EAS, EAS2) range back to the end of the 1980s, when computer power allowed the first spatial DNS computations. The upcoming amount of data required efficient handling and postprocessing. Typically, simulations were, and are still today, performed on a high-performance computer and afterwards postprocessed on other machines of opposite endianess. This required an endianess-independent file format for data handling.
Since the publication of EAS3 in the 1999, the software has been developed continuously by members of the involved institutes. Since 2007, EAS3 is also available via the heise
software directory. EAS3 is used by applications within the European PRACE project. The current version number is 1.6.7 from April, 2009.
). The data is organized as parameters with one parameter being a one-, two- or three-dimensional floating point array. Several of these parameters may be combined to one time step. This allows to store five-dimensional arrays. Data can be written in single-precision (32 Bit), double-precision (64 Bit) or quadruple-precision (128 Bit). Geometry information for the different directions are saved in the header of the file. It is also possible to store additional information in user defined arrays there. With the file size being limited only by the computer itself (e.g. file system), EAS3 files are suitable for large simulations and thus for high-performance computing
.
Outline of important functions
repository or one may download a zipped tar file. Makefiles for different machine types are included, providing an easy compilation. As linking of object files, created with different Fortran compilers can cause problems, binary packages (RPM
, .deb) are not offered up to now.
) binary data sets. The library provides that the data is always written big endian
. The resulting platform independence allows data exchange between different hardware architectures, e.g. supercomputer
s. The users benefits from the different methods provided for postprocessing, which can be automated using shell scripts.
. The MIT License is a free software license originating at the Massachusetts Institute of Technology (MIT)
. Specifically, it is a GPL-compatible permissive license, meaning that it permits reuse within proprietary software on the condition that the license is distributed with that software.
Direct numerical simulation
A direct numerical simulation is a simulation in computational fluid dynamics in which the Navier-Stokes equations are numerically solved without any turbulence model...
s.
EAS3 package
The complete package consists of libraries intended for usage in own codes and a separate command-line tool. It is written in FortranFortran
Fortran is a general-purpose, procedural, imperative programming language that is especially suited to numeric computation and scientific computing...
and C
C (programming language)
C is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....
and runs on all POSIX
POSIX
POSIX , an acronym for "Portable Operating System Interface", is a family of standards specified by the IEEE for maintaining compatibility between operating systems...
operating systems. The libraries include different numerical algorithms and subroutines for reading and writing files in the binary EAS3 file format. The read/write routines are provided in Fortran and C. Implemented numerical methods include, for example, Fast Fourier transform
Fast Fourier transform
A fast Fourier transform is an efficient algorithm to compute the discrete Fourier transform and its inverse. "The FFT has been called the most important numerical algorithm of our lifetime ." There are many distinct FFT algorithms involving a wide range of mathematics, from simple...
, Thomas algorithm
Tridiagonal matrix algorithm
In numerical linear algebra, the tridiagonal matrix algorithm , also known as the Thomas algorithm , is a simplified form of Gaussian elimination that can be used to solve tridiagonal systems of equations...
and interpolation
Interpolation
In the mathematical field of numerical analysis, interpolation is a method of constructing new data points within the range of a discrete set of known data points....
routines. The libraries are also suitable for vector computers.
History
EAS3 has been developed at the Institut für Aerodynamik und Gasdynamik (IAG) of the University of StuttgartUniversity of Stuttgart
The University of Stuttgart is a university located in Stuttgart, Germany. It was founded in 1829 and is organized in 10 faculties....
. The previous versions (EAS, EAS2) range back to the end of the 1980s, when computer power allowed the first spatial DNS computations. The upcoming amount of data required efficient handling and postprocessing. Typically, simulations were, and are still today, performed on a high-performance computer and afterwards postprocessed on other machines of opposite endianess. This required an endianess-independent file format for data handling.
Since the publication of EAS3 in the 1999, the software has been developed continuously by members of the involved institutes. Since 2007, EAS3 is also available via the heise
Heinz Heise
Heinz Heise is a publishing house based in Germany.- History :Heise was created in Hanover in 1949 as an address and telephone directory publisher, then later expanded to include magazines and loose leaf collections. In 2001, the company was divided into separate enterprises, all of which came...
software directory. EAS3 is used by applications within the European PRACE project. The current version number is 1.6.7 from April, 2009.
File Format
The EAS3 file format is used to store floating point data in IEEE format and to exchange the files between different computer architectures (little/big endianEndianness
In computing, the term endian or endianness refers to the ordering of individually addressable sub-components within the representation of a larger data item as stored in external memory . Each sub-component in the representation has a unique degree of significance, like the place value of digits...
). The data is organized as parameters with one parameter being a one-, two- or three-dimensional floating point array. Several of these parameters may be combined to one time step. This allows to store five-dimensional arrays. Data can be written in single-precision (32 Bit), double-precision (64 Bit) or quadruple-precision (128 Bit). Geometry information for the different directions are saved in the header of the file. It is also possible to store additional information in user defined arrays there. With the file size being limited only by the computer itself (e.g. file system), EAS3 files are suitable for large simulations and thus for high-performance computing
High-performance computing
High-performance computing uses supercomputers and computer clusters to solve advanced computation problems. Today, computer systems approaching the teraflops-region are counted as HPC-computers.-Overview:...
.
Functionality
The actual EAS3 executable is a command-line interface for alteration of EAS3 files. The implemented commands range from basic operations, e.g. simple computations, file operations, to rather complex operations like Fourier transformation or the computation of derivatives. Specific commands for DNS data are also available, e.g. the lambda2 vortex criterion. As the commands are read from standard input, EAS3 may be used in shell scripts for automated calls.- file management: rearrangement, attaching two files, cutting
- conversion to other file formats (ASCII, Covise, Tecplot)
- mathematical operationes: basic operations, logarithm, etc.
- derivatives und integration
- interpolation
- data reduction: mean values, RMS-values, etc.
- Fourier transformation: single/double, real/complex
- DNS specific: vortex criterion
Installation
The sources can be obtained directly from the CVSConcurrent Versions System
The Concurrent Versions System , also known as the Concurrent Versioning System, is a client-server free software revision control system in the field of software development. Version control system software keeps track of all work and all changes in a set of files, and allows several developers ...
repository or one may download a zipped tar file. Makefiles for different machine types are included, providing an easy compilation. As linking of object files, created with different Fortran compilers can cause problems, binary packages (RPM
RPM Package Manager
RPM Package Manager is a package management system. The name RPM variously refers to the .rpm file format, files in this format, software packaged in such files, and the package manager itself...
, .deb) are not offered up to now.
Advantages
The main profit for the programmer is the easy implementation of reading/writing large (>2GBByte
The byte is a unit of digital information in computing and telecommunications that most commonly consists of eight bits. Historically, a byte was the number of bits used to encode a single character of text in a computer and for this reason it is the basic addressable element in many computer...
) binary data sets. The library provides that the data is always written big endian
Endianness
In computing, the term endian or endianness refers to the ordering of individually addressable sub-components within the representation of a larger data item as stored in external memory . Each sub-component in the representation has a unique degree of significance, like the place value of digits...
. The resulting platform independence allows data exchange between different hardware architectures, e.g. supercomputer
Supercomputer
A supercomputer is a computer at the frontline of current processing capacity, particularly speed of calculation.Supercomputers are used for highly calculation-intensive tasks such as problems including quantum physics, weather forecasting, climate research, molecular modeling A supercomputer is a...
s. The users benefits from the different methods provided for postprocessing, which can be automated using shell scripts.
Disadvantages
Being specialized on structured grids may be a problem for some users. Up to now, only cartesian grids or a representation of the data in spectral space are implemented. Data in other types of data alignment, e.g. cylindrical coordinates, can be stored in EAS3 files but the existing postprocessing commands may not be used. As the usually used visualization programs do not support the EAS3 file format directly, it is often necessary to covert the data to the corresponding file format. Commands in the EAS3 program are given by a text interface, a graphical user interface does not exist. Completion of the commands in the EAS3 command line provides support for interactive usage but for an extensive help, the descriptions on the webpage are necessary.License
EAS3 is published under the MIT LicenseMIT License
The MIT License is a free software license originating at the Massachusetts Institute of Technology . It is a permissive license, meaning that it permits reuse within proprietary software provided all copies of the licensed software include a copy of the MIT License terms...
. The MIT License is a free software license originating at the Massachusetts Institute of Technology (MIT)
Massachusetts Institute of Technology
The Massachusetts Institute of Technology is a private research university located in Cambridge, Massachusetts. MIT has five schools and one college, containing a total of 32 academic departments, with a strong emphasis on scientific and technological education and research.Founded in 1861 in...
. Specifically, it is a GPL-compatible permissive license, meaning that it permits reuse within proprietary software on the condition that the license is distributed with that software.
Usage
- Transition group at the Institute of Aerodynamics and Gasdynamics (IAG) of the University of Stuttgart: http://www.iag.uni-stuttgart.de
- Computational Fluid Dynamics Laboratory of the University of Arizona: http://cfd.ame.arizona.edu
- Institute of Fluid Dynamics, Eidgenössische Technische Hochschule Zürich: http://www.ifdmavt.ethz.ch
- Lehrstuhl für Aerodynamik at the Technical University Munich (high-speed aerodynamics group): http://www.aer.mw.tum.de
Related file formats
- Common Data FormatCommon Data FormatCommon Data Format is a library and toolkit that has been developed by NASA. The software is an interface for the storage and manipulation of multi-dimensional data sets.-See also:* CGNS * EAS3...
(CDF) - CGNSCGNSCGNS stands for CFD General Notation System. It is a general, portable, and extensible standard for the storage and retrieval of CFD analysis data. It consists of a collection of conventions, and free and open software implementing those conventions...
(CFDComputational fluid dynamicsComputational fluid dynamics, usually abbreviated as CFD, is a branch of fluid mechanics that uses numerical methods and algorithms to solve and analyze problems that involve fluid flows. Computers are used to perform the calculations required to simulate the interaction of liquids and gases with...
General Notation System)
- FITSFITSFlexible Image Transport System is a digital file format used to store, transmit, and manipulate scientific and other images. FITS is the most commonly used digital file format in astronomy...
(Flexible Image Transport System) - GRIBGRIBGRIB is a mathematically concise data format commonly used in meteorology to store historical and forecast weather data...
(GRIdded Binary) - Hierarchical Data FormatHierarchical Data FormatHierarchical Data Format is the name of a set of file formats and libraries designed to store and organize large amounts of numerical data...
(HDF) - NetCDFNetCDFNetCDF is a set of software libraries and self-describing, machine-independent data formats that support the creation, access, and sharing of array-oriented scientific data. The project homepage is hosted by the Unidata program at the University Corporation for Atmospheric Research...
(Network Common Data Form) - TecplotTecplotTecplot is the name of a family of visualization software tools developed by Tecplot, Inc., which is headquartered in Bellevue, Washington.-Tecplot Chorus:...
binary files - XMDFXMDFXMDF is a library providing a standard format for the geometry data storage of river cross-sections, 2D/3D structured and unstructured meshes, geometric paths through space, and associated time data. XMDF uses HDF5 for cross-platform data storage and compression...
(eXtensible Model Data Format)