From: bangerth Date: Fri, 31 Aug 2007 18:37:45 +0000 (+0000) Subject: Get rid of the FAQ and link to the Wiki instead. X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c5678555ec34b7ace3e35747e1181a31dccd7698;p=dealii-svn.git Get rid of the FAQ and link to the Wiki instead. git-svn-id: https://svn.dealii.org/trunk@15095 0785d39b-7218-0410-832d-ea1e28bc413d --- diff --git a/deal.II/doc/faq.html b/deal.II/doc/faq.html deleted file mode 100644 index 68767939f9..0000000000 --- a/deal.II/doc/faq.html +++ /dev/null @@ -1,533 +0,0 @@ - - - - The deal.II FAQ - - - - - - - - -

The deal.II FAQ

- -

- This is a short list of questions that are asked frequently on the - deal.II mailing list, so we collect short answers - for them here. If you have a question that is not answered here, it - is probably a good idea to first browse through the - mailing list archives first, as there many - questions have already been discussed. -

- -

I tried to install deal.II - on system X and it does not work. -
How do I change the compiler? -
I am having trouble linking with PETSc! -
I cannot link with BLAS or LAPACK even if the - libraries exist -
Can I use deal.II on a - Windows platform? -
Can I use deal.II on an - Apple MacIntosh? -
Does deal.II support parallel - computing? -
I can't build the online documentation under Cygwin! -
My program compiles and links under Cygwin, but - it issues a run-time error saying that libXXX.DLL cannot - be found! -
Can I use/implement triangles/tetrahedra - in deal.II? -
Can I solve problem XXX with - deal.II? -
How do I solve problem XXX with - deal.II? -
Can I solve problems over complex numbers? -
I want to contribute to the development - of deal.II! -

- - - -

- I tried to install deal.II on system X and it does not work. -

- Even if people reading this list and especially people managing this list - belong to the most able programmers in the universe (and a decent number of - parallel universes), all of us need data to find errors. So, whatever went - wrong, paste the error message into your email. If appropriate, add lines - from the file producing the error. -

- How do I change the compiler? -

- deal.II can be compiled by a number of compilers - without problems (see the section prerequisites in the readme - file). If the ./configure script does not pick the right one, - selecting another is simple, and described in an - according - section in the readme file. -

- -

- I am having trouble linking with PETSc! -

- Let's put it this way: the configuration of PETSc is really - non-trivial, and it isn't made much easier by the - documentation (or lack thereof) that the library's developers - provide and the constant incompatible changes they make to - everything. We've got the interface to PETSc working pretty well on - many platforms, but there are cases where PETSc requires linking - with other libraries that the deal.II Makefiles are unaware of. -

- -

- If you get linker errors about undefined symbols, try to figure out - which library these functions reside in. If you can't manage to get - this going yourself, feel free to send email to the mailing list. -

- -

- In general, try to get things going first by configuring PETSc with - options --with-shared=0 --with-mpi=0 - --with-clanguage=C++ and then configuring - deal.II with the option - --disable-shared. -

- - -

- I cannot link with BLAS or LAPACK even if the libraries exist -

This is probably due to the introduction of the new GNU FORTRAN - Compiler gfortran. If those libraries were compiled with - gfortran and you have the old g77 installed, then - the library -lgfortran is missing. Or vice versa - -lg2c might be missing. Check config.log for the - test for BLAS to see if it complains about missing symbols - indicating such a thing. If so, install the missing compiler. -

- Can I use deal.II on a Windows platform? -

- First the good news: yes, you can. Still, this answer needs to be - more specific. The configuration program for - deal.II expects a Unix-like environment. This is - provided by the cygwin - system. You should try to use a current cygwin distribution. - A look at the mail - archive might be advisable in case of difficulties. -

- -

- Also note that on some installations of Cygwin, one of the system - header files used the proprocessor to define quad to - quad_t. Since deal.II uses the name - quad as a function name, the name is sometimes - replaced, sometimes not, depending on the order of include files and - whether the respective system header was included at all. This leads - to compilation errors. -

- -

- Since the offending preprocessor define is only active when - _POSIX_SOURCE is not set, deal.II - releases after version 3.4 set this flag, to avoid the - problem, but releases up to and including version 3.4 may not - work. For more information, refer to the - mailing list - thread on this subject, and follow-up messages. -

- - -

Other Windows compilers

- As long as a compiler is sufficiently standards conforming, and has - a command line interface, it may be used to compile the library. In - order to do so, the automatic configuration needs to recognize the - compiler, and be able to specify some flags, for example for - optimization. Presently, except for gcc and Intel C++, we do not - support any of the genuine Windows compilers, such as Visual C++, or - Borland C++. However, if you want to add support for them, just look - at how this is done in aclocal.m4 for the existing - compilers, and add support for the one you prefer. You may also want - to get into contact with us on the matter. -

- - -

- I can't build the online documentation under Cygwin! -

- The Perl utility from Cygwin distribution (up to version 5.6.1-2) - contains a bug that causes a "permission denied" error with in-place - editing (using the -pi switch). This bug prevents - building the online documentation from the source files. To solve - this problem there are two workarounds as described in an article on - the Cygnus - Solutions mailing list. First, one should specify an - explicit extension in all makefiles, i.e. replace all - -npi or -pi options with - -npi~ or -pi~ for example. Second, apply a - patch to the source code of the perl utility and recompile. -

- -

- My program compiles and links under Cygwin, but it issues a - run-time error saying that libXXX.DLL cannot - be found! -

- With Version 5.1.0, deal.II creates and uses shared - libraries (DLLs) under cygwin. These DLLs will be linked to your program - at run-time, which requires Windows to know where the DLLs are stored. - Windows looks for DLLs in the execution path of your program, in the - Windows system directories, and in every directory specified in the - PATH environment variable. To do this, type -

- -

- export PATH=$PATH:/usr/local/lib/deal.II/lib -

- -

- (or the place where you have installed deal.II, respectively) in the shell - prior to execution, or add this line to .bashrc or - .bash_profile. - To disable shared libraries, run ./configure --disable-shared - and compile deal.II again (with make all). -

- - -

- Can I use deal.II on an Apple MacIntosh? -

- Yes, at least on the more modern OS X operating systems this works - just fine, as long as the developer tools like the GCC compiler, - PERL, etc are installed. The only issue we are currently aware of is - that if deal.II is configured to interface with - PETSc, then PETSc needs to be configured with the - --with-x=0 flag to prevent linking in the X11 libraries - (you probably won't need them anyway). -

- -

- Does deal.II support parallel computing? -

- Yes. If you use the --with-multithreading - --enable-multithreading flags when you run ./configure - (see the README file), then the - library will be set up to use multiple threads for various tasks, and you - can also use multiple threads in your program. See the example programs - to see how to do the latter. On machines with more than one processor - (i.e. SMP machines), using this functionality makes a lot of sense and can - significantly accelerate a program. -

- -

- By default, deal.II does not support operations on - clusters of computers that communicate via MPI. However, it also doesn't - prohibit you from doing so in your application programs (and there are a - number of programs that actually do this), it just doesn't implement - anything that actively uses MPI functionality. -

- -

- On the other hand, newer versions of deal.II have - interfaces to the PETSc library that implements a lot of functionality for - distributed linear algebra, i.e. for operations on vectors and matrices that - are distributed across a cluster of machines coupled via MPI. By using these - wrapper classes for linear algebra, it is possible to implement programs - that work on truly large problems by distributing computations. In addition, - we have functions that call into METIS to generate partitionings of triangulations. -

- -

- For questions how to set up deal.II to use PETSc and - METIS, refer to the readme file. -

- -

Can I use/implement triangles/tetrahedra in - deal.II?

- No, you can't. The basic data structures are too much - tailored to quadrilaterals and hexahedra. Implementing other cells - amounts to re-implementing nearly all grid and DoF classes from - scratch. On the other hand, the restriction to quadrilaterals and - hexahedra avoids a large number of run-time computations and makes - the library as fast as it is. -

- - -

Can I solve problem XXX with deal.II?

- The simple answer is: if it can be written as a PDE, then this is - possible as evidenced by the many publications in widely disparate - fields obtained with the help of deal.II. The - more complicated answer is: deal.II - is not a problem-solving environment, it is a toolbox that supports - you in solving a PDE by the method of finite elements. You will have - to implement assembling matrices and right hand side vectors - yourself, as well as nonlinear outer iterations, etc. However, you - will not need to care about programming a triangulation class that - can handle locally refined grids in one, two, and three dimensions, - linear algebra classes, linear solvers, different finite element - classes, etc. -

- -

- To give only a very brief overview of what is possible, here is a - list of the nontrivial problems that were treated by the programs - that the main authors alone wrote to date: -

Time-dependent acoustic and elastic wave equation, including - nonlocal absorbing boundary conditions; -
Stokes flow discretized with the discontinuous Galerkin finite - element method; -
General hyperbolic problems including Euler flow, using the - discontinuous Galerkin finite element method; -
Distributed parameter estimation problems; -
Mixed finite element discretization of a mortar multiblock formulation - of the Laplace equation; -
Large-deformation elasto-plasticity in the simulation of plate - tectonics. -

- -

- To illustrate the complexity of the programs mentioned above we note - that most of them include adaptive mesh refinement tailored to the - efficient computation of specific quantities of physical interest - and error estimation measured in terms of these quantities. This - includes the solution of a so-called dual problems, that means - e.g. for the wave equation the solution of a wave equation solved - backward in time. -

- -

- Problems other users of deal.II have solved include: -

Elastoplasticity; -
Porous media flow; -
Crystal growth simulations; -
Fuel cell simulations and optimization; -
Fluid-structure interaction problems; -
Time dependent large deformation problems for metal forming; -
Contact problems; -
Viscoelastic deformation of continental plates; -
Glacial ice flows; -
Thermoelastoplastic metal forming; -
Eulerian coordinates problems in biomechanical modeling. -

- Some images from these applications can be found on the - deal.II Wiki. - Probably, many other problem types are solved by the many users - which we do not know of directly. If someone would like to have his - project added to this page, just contact us. -

- -

How do I solve problem XXX - with deal.II?

- There is no general rule on how to attack implementing a program to - solve your particular problem. However, the way most often taken is - to look at one of the - example programs from the tutorial and modify it - such that it solves your equation. This way, a number of problems - can be solved at relatively small effort. -

- -

- If your class of problem does not allow taking and modifying one of - the examples programs, then you have to write something up - yourself. The example programs may nevertheless be a good guide on - how to program with deal.II. -

- -

Can I solve problems over complex numbers?

- Yes, you can, and it has been done numerous times with - deal.II. However, we have a standard - recommendation: consider such problems as systems of partial - differential equations, where the individual components of the - solution are the real and imaginary part of your unknown. The reason - for this is that for complex-valued problems, the product - <u,v> of two vectors is not the same as - <v,u>, and it is very easy to get this wrong in many - places. If you want to avoid these common traps, then the easiest - way around is to split up you equation into two equations of real - and imaginary part first, and then treat the resulting system as a - system of real variables. This also makes the type of linear system - clearer that you get after discretization, and tells you something - about which solver may be adequate for it. -

- -

I want to contribute to the development - of deal.II!

- deal.II is Open Source -- this not only implies - that you as everyone else has access to the source codes, it also - implies a certain development model: whoever would like to - contribute to the further development is invited to do so! -

- -

- This model follows a small number of simple rules. The first and - basic one is that if you have something that might be of interest to - others as well, you are invited to send it to the list for possible - inclusion into the library and use by others as well. Such additions - useful to others are, for example: -

new backends for output in a new graphical format; -
input filters for some kind of data; -
tool classes that do something that might be interesting to use - in other programs as well. -

- In general, once you start to use something you wrote for one - project in a second project, this is something that would make up a - good addition to the entire library! -

- -

- If you consider providing some code for inclusing into the library, - these are the simple rules of gaining reputation in the Open Source - community: -

your reputation grows with the number and complexity of your - contributions; -
your reputation with the maintainers of the library also grows - with the degree of conformance of your proposed additions with - the administrative rules stated below; -
originators of code are credited full authorship. -

- -

- In order to allow that a library remains a consistent piece of - software, there are a number of administrative rules: -

there are a number of maintainers that decide what goes into - the library; -
maintainers are benevolent, i.e. in general they want your - addition to become part of the library; -
however, they have to evaluate additions with respect to some - criteria, among which are -
- value for others; -
- whether it fits into the general framework (meaning that - if your contribution requires the installation of some - obscure other library that people do not usually have, then - that must be discussed; alternatively, a way must be provided - to disable your contribution on machines that do not have this - lib); -
- completeness and amount of documentation; -
- existence and completeness of error checking through - assertions. -
-

- -

- However, again: the basic rule is that if you think your addition is - interesting to others, there most probably is a way to get it into - the library! -

- - - diff --git a/deal.II/doc/navbar.html b/deal.II/doc/navbar.html index e89591cadf..31bb738929 100644 --- a/deal.II/doc/navbar.html +++ b/deal.II/doc/navbar.html @@ -5,7 +5,7 @@ deal.II navigation bar - + @@ -20,7 +20,7 @@

README
- FAQ
+ FAQ
News
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A fairly complete C++ compiler. We usually use - gcc3.x but also some - others. Various working compilers - are listed above. egcs1.x and older gcc versions will not - work, however. For gcc 2.96, see the Frequently Asked Questions. Also, Sun - Workshop C++ 5.0 will not work since it does not support - template member functions, Sun Forte C++ 5.5 will not work since it - does not understand a number of other advanced template features, - and IBM C Set++ 3.0 will not - work since they only have non-ISO header file names (with - appended .h. Version 5.0 does not work since they do not - allow the declaration of explicit specializations and a - larger number of other techniques that are used in the - library, see the link in the list above. The SGI MIPSpro + gcc3.x or + 4.x but also some others. Various working compilers + are listed above. We do not support gcc versions older than + 3.2 any more at this time. Except for the most recent versions, Sun + Workshop C++ and Sun Forte C++ will not work since they only + supports a limited subset of C++. The most recent versions of + IBM C Set++ should work. The SGI MIPSpro compiler 7.3 or earlier will not work since it is not C++ standard conforming. The MIPSpro compiler 7.4 will also not work since it is still too buggy.

- Note that we have supported egcs 1.1.x in previous releases - of the library (up to deal.II 3.0.x), - but due to some missing feature in the support of Standard - C++, we now only support later versions of gcc for releases - of deal.II after version 3.0.x. Beyond - that, we frequently compile deal.II with - newer gcc snapshots, to ensure that the library will - compile with upcoming releases. -

We are interested in writing portable C++, so if you find something that does not work with your compiler, we are @@ -941,7 +923,7 @@ the library may be found on the homepage of deal.II, or in the - Frequently Asked Questions section. + Frequently Asked Questions section. If you don't find anything there, feel free to ask if you have any problems with deal.II. If a question is of general interest, you may want to use our mailing list,