Welcome to the oomph-lib homepage
oomph-lib is an object-oriented, open-source
finite-element library for the simulation of multi-physics
problems. It is developed and maintained by Matthias Heil and Andrew Hazel of the
School of
Mathematics at The
University of Manchester, along with many other contributors.
See the change
log page for an overview of the changes made since the previous
release.
What is it [and what is it not]?
oomph-lib is:
- an object-oriented, open-source finite-element library for the
simulation of multi-physics problems.
oomph-lib is not:
- a GUI-based, mouse-driven "package".
You must write your own C++ driver codes to specify your problem,
using oomph-lib's high-level objects. Once the problem
is formulated, the main function can be as simple as
this:
main()
{
MyProblem problem;
problem.newton_solve();
}
oomph-lib provides the state of the art infrastructure
for the problem formulation and solution. The library contains a
large number of elements, meshes, timesteppers, solvers, etc. which
can be combined to solve any problem.
The library is supplied with extensive on-line documentation
which includes:
-
This provides a relatively brief, constructive "top-down"
introduction to the maths of the finite element method, and
explains its object-oriented implementation in
oomph-lib.
-
A bottom-up discussion of
oomph-lib's overall data
structure, including a complete, cross-referenced index of all
oomph-lib's classes (generated by Doxygen).
-
The (Not-So-)Quick
Guide provides a "quick" introduction on how to create new
instances of
oomph-lib's fundamental objects:
Problems, Meshes, and
Elements.
-
We provide a large number of verified and documented example
problems.
- The example problems are arranged in
order of increasing complexity and can be used as chapters in a
self-study course. Comments and exercises are provided to encourage
further exploration of
oomph-lib's capabilities.
- The individual examples are as
self-contained as possible and can be used as quick guides to
particular features of
oomph-lib. ("How do I solve
time-dependent problems?"; "How do I enable spatial adaptivity?";
"How do I write my own meshes?"; etc.)
- The examples codes should be regarded
as templates for your own driver codes: Examine the list of examples and try
to find one that resembles the problem that you wish to solve. For
most "classical" problems (e.g. the solution of the Navier-Stokes
equations with standard boundary conditions), very few
modifications are required (e.g. adjusting the mesh to a different
domain, changing the boundary and/or initial conditions, etc). If
you wish to solve a non-standard problem, or one for which
oomph-lib does not (yet) provide elements or meshes,
it is easy to write your own, following the detailed instructions
provided in the documentation.
Features
- Large number of fully-developed and carefully-validated element
types for the solution of:
- The Poisson equation
- The unsteady heat equation
- The linear wave equation
- The advection-diffusion equation
- The Navier-Stokes equations, incl. free-surfaces, in Cartesian
and axisymmetric co-ordinates.
- The equations of large-displacement solid mechanics, based on
the principle of virtual displacements in cartesian and
axisymmetric geometries; with arbitrary constitutive
equations.
- Shell and beam elements, based on a geometrically non-linear
formulation.
- ...and many others.
[Note: Most elements are implemented in a
dimension-independent formulation]
- It is easy to formulate new elements for problems that are not
included in the above list.
- It is easy to combine any of the above elements to
"multi-physics" elements, allowing e.g.
- the solution of fluid-structure interaction problems
- the simulation of unsteady heat conduction in an elastic body
that undergoes large displacements
- free-surface problems
- etc.
- Parallel processing capabilities.
- Full spatial and temporal adaptivity. All elements listed above
support quad-tree/octree-based mesh refinement procedures and
adaptive timestepping.
- A wide range of meshes; new meshes can easily be added to the
library.
oomph-lib can also use meshes that are
generated by third-party (commercial) mesh generators.
- The ability to solve problems in domains with time-dependent,
curvilinear boundaries.
oomph-lib treats all problems as non-linear
problems and uses Newton's method as the default non-linear solver.
Within this framework, linear problems are special cases for which
the Newton iteration converges in one step. The linear systems
arising during the Newton iteration can be solved with a variety of
direct and iterative solvers. Continuation methods (Keller's
arclength method and displacement-control for solid mechanics
problems) are implemented.- A large number of fully documented example
codes. All examples include an introduction to the
mathematical/physical problem, a detailed discussion of the driver
code, a discussion of the results (incl. comparisons against
analytical solutions where appropriate) and exercises and
comments.
- The library has extensive self-test facilities. It can be
compiled with a PARANOID flag switched on or off. If the flag is
set during compilation, the code performs a large number of
self-tests during its execution. If things go wrong, code execution
terminates gracefully and diagnostic output is generated to help
pinpoint the problem. Of course, the tests introduce an additional
run-time overhead, so can be switched off in production runs.
During development, range checking on all array-based objects,
(vectors, matrices, tensors, etc) can be enabled separately by
using the RANGE_CHECKING flag, but introduces considerable run-time
overhead.
How do I get/install the code?
Downloads
oomph-lib is hosted on and distributed via GitHub at
https://github.com/oomph-lib/oomph-lib.
For more information on how to download and install the library see
the installation
guide.
Prerequisites
oomph-lib has been/is primarily being developed in
Linux so it is well tested there. However several people
successfully run it on Windows and Mac OS X. Our continuous
integration on GitHub currently checks Linux and Mac OS X builds.
In order to minimise
the dependence on external libraries we include "frozen" versions
of certain external libraries (METIS, SuperLU, ...) with our
distribution. The idea is that you should only have to unpack,
build and install one distribution to produce the fully compiled
library, the html-based documentation and working example
codes.
For this purpose you must have:
- A computer with a linux (or unix) operating system. [Note
for windows users: We believe that
oomph-lib can
be installed in a windows environment, using cygwin, though we haven't tried this
for a long time.]
- Compilers for C++, C and Fortran77. The open-source GNU gcc compiler suite version 9.3.0. or
later is fine. [ Note: The Fortran77 and C compilers are
only required to compile some external libraries --
oomph-lib itself is written entirely in C++. We assume
that your C++ compiler can handle the C++11 standard. If it doesn't
you may have to add the -std=c++11 option to the
CXXFLAGS during the configure stage.]
The following programs are helpful but not essential:
- GNU's autoconf, automake and libtool are required if
you wish to add additional features to your local copy of
oomph-lib; see the oomph-lib
download page for more details.
- python3 is needed
to analyse the results of the extensive self-tests that may be
performed at the end of the installation to verify that the build
process was completed successfully. If python3 is not available, the
self-test will compile and run all test codes but it will not be
possible to verify the correctness of the results.
- doxygen is needed to build
a local copy of
oomph-lib's extensive online
documentation. If doxygen is not installed on your system you can
consult the latest version of the online documentation on the oomph-lib
homepage.
The oomph-lib distribution is built under autoconf / automake control,
making the installation completely straightforward. We provide two
main installation mechanisms:
oomph-lib can be built/installed/tested with GNU's
standard configure; make; make install; make check
procedure.- We also provide a customised build script,
autogen.sh, that guides the "non-expert" user through
the installation. The script facilitates the specification of
various build options, such as optimisation levels etc.
Subject to the minimum requirements, listed above, you should be
able to install and use our libraries "anywhere". However, as
anybody who has ever ported any code to a different platform knows,
things are rarely that simple -- even with autoconf, automake and libtool... Having said
that, we have successfully installed and tested our installation on
the following platforms:
- Ubuntu (version 16.04) with gcc compilers (version 5.4.0). The
tests included the MPI part of the library, which we compiled with
OpenMPI (version
1.10.2).
- ...
Preparing a ubuntu box for oomph-lib
Typically, when we install oomph-lib on a machine with
a new (default) installation of ubuntu, we install at least the
following additional packages (here listed with full apt-get syntax,
so you can cut and paste):
apt-get install git
apt-get install make
apt-get install automake
apt-get install libtool
apt-get install libtool-bin
apt-get install cmake
apt-get install python2
apt-get install autoconf
apt-get install doxygen
apt-get install gfortran
apt-get install g++
Building the pdf version of the tutorials also requires a comprehensive latex
installation:
apt-get install texlive texlive-latex-extra texlive-font-utils
If you want it all in one go (particularly useful if you have
to prefix the apt-get with sudo):
apt-get install git make automake libtool libtool-bin cmake python2 autoconf doxygen gfortran g++ texlive texlive-latex-extra texlive-font-utils
How do I get started?
oomph-lib contains a lot of code and a lot of
documentation. How to get started obviously depends on your
background: Are you familiar with the finite element method? How
good is your knowledge of C++? Etc. Here are some possible
"routemaps" around the library:
- You are familiar with the finite element method and have a
fairly good knowledge of C++
- Have a look through the list of example codes to
get a feeling for
oomph-lib's capabilities. Pick a
problem that interests you and study the associated tutorial. Copy
the driver code into your own directory and play with it.
- Once you have played with a few example codes, you may wish to
to learn more about
oomph-lib's overall data structure,
or find out how to
optimise the library for your particular application.
- You have never used finite element methods but have a fairly
good knowledge of C++
- Study the "Top Down"
introduction. This document includes a "low tech" overview of
the mathematical/theoretical background and contrasts procedural
implementations of the finite element method with the
object-oriented approach adopted in
oomph-lib.
- Consult the (Not-So-)Quick-Guide to learn
how to construct basic
oomph-lib objects for your
problem: Problems, Meshes,
FiniteElements, etc.
- Continue with the steps suggested above.
- You have never used finite element methods and are a
newcomer to C++
- Buy Daoqi Yang
brilliant book
C++ and Object-Oriented Numeric Computing for Scientists and
Engineers. Read it! Pretty much everything in this book is
relevant for some parts of
oomph-lib. You should at
least understand:
- The procedural aspects of C++ (basic types, functions and
control structures).
- Namespaces.
- Classes (private, protected and public members; inheritance and
multiple inheritance; virtual and pure virtual functions; base
classes and derived classes; static and dynamic casts).
- Templates and template instantiations.
- The standard template library (STL).
- Continue with the steps suggested above.
