how to link an external library with YADE

It should be enough to add the library in your scons.profile.
You can just compile with "scons SHCCFLAGS="-lIcoFoam", then it will be added into the profile (and next time, you just type "scons"), else you edit the profile and include it manually.
If it needs a path, you add it to LIBPATH, the same way.
Do you plan to commit this coupling code one day? It would be a very interesting development.

Bruno

Hi Bruno,
Thanks a lot for your reply. Yes, I plan to commit this coupling code one day.
I tried your suggestion to link the library, but one more problem still exists when I use the engine. Please see bellow:

131 FATAL yade.Omega /home/tao/trunk/core/Omega.cpp:204 loadPlugins: /home/tao/YADE/lib/yade-bzr2866/plugins/libplugins.so: undefined symbol `icoFoam(..........)'

Actually, 'icoFoam' is just the function I want to use in the fluidDragForce engine. I'm not sure why YADE cannot locate the engine. Do I need to explicitly write the library path in the fluidDragForce.cpp?

Thanks.

Cheers,
Tao

The libpath is for the linker. You don't type it in any cpp usually, but
add the path to linker flags.
What is the output of "scons -h"? and in which directory is the library
on your system?
Sorry to ask basic questions, but, you recompiled right?

Hi Bruno,
The information in scons.profile-default is:

PREFIX = '/home/tao/YADE'
features = 'gts,log4cxx,opengl,openmp,qt4,vtk'
CPPPATH = '/usr/include/vtk-5.0:/usr/include/vtk-5.2:/usr/include/vtk-5.4:/usr/include/vtk-5.6:/usr/include/vtk:/home/tao/yadeopenfoam:/usr/include/eigen2'
LIBPATH = '/home/tao/yadefluid'
CXXFLAGS = []
SHCCFLAGS = ['-lIcoFoam', '-fPIC']

As for the last line, I have to add '-fPIC' to process the compilation. If not, some problems will occur. The compilation is correct with the message: "scons: done building targets." However, when I tried to test this engine in my script, problems as posted before occur.

The output of "scons -h" are listed as bellow:

tao@ubuntu:~/trunk$ scons -h
scons: Reading SConscript files ...
@@@ Using profile default (scons.profile-default) @@@
Eigen 2 math library will be used
Yade version is `bzr2866' (bzr2866), installed files will be suffixed with `-bzr2866'.
All intermediary files will be in `/home/tao/build-bzr2866'.
Checking whether c++ compiler "g++" works...(cached) yes
Finding libstdc++ library... (cached) /usr/lib/libstdc++.so.6
Checking for pthread_exit(NULL) in C library pthread... (cached) yes
Checking for Python development files... (cached) ok
Checking for C++ header file numpy/ndarrayobject.h... (cached) yes
Checking for required python modules... (cached) all ok
Checking boost libraries... (cached) all ok
Checking for C++ header file boost/foreach.hpp... (cached) yes
Checking for C++ header file Eigen/Core... (cached) yes
Checking for C++ header file loki/NullType.h... (cached) yes
Checking for glutGetModifiers() in C++ library glut... (cached) yes
Checking for QGLViewer() in C++ library qglviewer-qt4... (cached) yes
Checking for vtkInstantiator::New() in C++ library vtkCommon... (cached) yes
Checking for gts_object_class() in C++ library gts... (cached) yes
Checking for log4cxx::Logger::getLogger("") in C++ library log4cxx... (cached) yes
scons: done reading SConscript files.

PREFIX: Install path prefix
    default: /usr/local
    actual: /home/tao/YADE

runtimePREFIX: Runtime path prefix; DO NOT USE, inteded for packaging only.
    default: None
    actual: /home/tao/YADE

variant: Build variant, will be suffixed to all files, along with version.
    default:
    actual:

debug: Enable debugging information (yes|no)
    default: 0
    actual: False

gprof: Enable profiling information for gprof (yes|no)
    default: 0
    actual: False

optimize: Turn on optimizations (-1, 0 or 1); negative value sets optimization based on debugging: not optimize with debugging and vice versa.
    default: -1
    actual: True

PGO: Whether to "gen"erate or "use" Profile-Guided Optimization (|gen|use)
    default:
    actual:

features: Optional features that are turned on
    (all|none|comma-separated list of names)
    allowed names: opengl log4cxx cgal openmp gts vtk gl2ps qt4 sphere-padder never_use_this_one subdomains
    default: log4cxx,opengl,gts,openmp,vtk,qt4
    actual: gts log4cxx opengl openmp qt4 vtk

jobs: Number of jobs to run at the same time (same as -j, but saved)
    default: 2
    actual: 2

buildPrefix: Where to create build-[version][variant] directory for intermediary files
    default: ..
    actual: ..

hotPlugins: Files (without the .cpp extension) that will be compiled separately even in the monolithic build (use for those that you modify frequently); comma-separated.
    default:
    actual:

chunkSize: Maximum files to compile in one translation unit when building plugins. (unlimited if <= 0, per-file linkage is used if 1)
    default: 7
    actual: 7

version: Yade version (if not specified, guess will be attempted)
    default: None
    actual: None

realVersion: Revision (usually bzr revision); guessed automatically unless specified
    default: None
    actual: None

CPPPATH: Additional paths for the C preprocessor (colon-separated)
    default: /usr/include/vtk-5.0:/usr/include/vtk-5.2:/usr/include/vtk-5.4:/usr/include/vtk-5.6:/usr/include/vtk
    actual: /usr/include/vtk-5.0 /usr/include/vtk-5.2 /usr/include/vtk-5.4 /usr/include/vtk-5.6 /usr/include/vtk /home/tao/yadeopenfoam /usr/include/eigen2

LIBPATH: Additional paths for the linker (colon-separated)
    default: None
    actual: /home/tao/yadefluid

libstdcxx: Specify libstdc++ location by hand (opened dynamically at startup), usually not needed
    default: None
    actual: None

QT4CXX: Specify a different compiler for files including qt4; this is necessary for older qt version (<=4.7) which don't compile with clang
    default: None
    actual: None

QT4DIR: Directory where Qt4 is installed
    default: /usr/share/qt4
    actual: /usr/share/qt4

PATH: Path (not imported automatically from the shell) (colon-separated)
    default: None
    actual: None

CXX: The c++ compiler
    default: g++
    actual: g++

CXXFLAGS: Additional compiler flags for compilation (like -march=core2).
    default: None
    actual:

march: Architecture to use with -march=... when optimizing
    default: native
    actual: native

execCheck: Name of the main script that should be installed; if the current one differs, an error is raised (do not use directly, only intended for --rebuild
    default: None
    actual: None

defThreads: No longer used, specify -j each time yade is run (defaults to 1 now)
    default: -1
    actual: -1

SHCCFLAGS: Additional compiler flags for linking (for plugins).
    default: None
    actual: -lIcoFoam -fPIC

QUAD_PRECISION: typedef Real as long double (=quad) (yes|no)
    default: 0
    actual: False

brief: Don't show commands being run, only what files are being compiled/linked/installed (yes|no)
    default: True
    actual: True

Use scons -H for help about command-line options.

Thanks a lot.

Cheers,
Tao

> > and in which directory is the library
> on your system?

Hi Bruno,
The directory of the library is $HOME/yadefluid and the directory of yade is $HOME/trunk on my computer system.
I'm not sure if there is something wrong with the link or the library itself. I will try to check it.

Thanks a lot.

Cheers,
Tao

Ok thanks, I was not sure if it was yade dir or lib dir.
Can you can compile/run a small example programs using this lib?
Is it better if you add "-licoFoam" to CXXFLAGS instead of of SHCCFLAGS
(or both, it can't hurt)?

Hi,
Now I can link the library "-licoFoam" with YADE by editing the line "env.Append(CPPPATH='',LIBPATH='/home/tao/YADE/lib/yade-0.11.1/pkg-dem',LIBS='IcoFoam',CXXFLAGS='',SHCCFLAGS='')" in $HOME/trunk/SConstruct and the line in $HOME/trunk/scons.profile-default.
Actually, this libIcoFoam.so links YADE with one CFD software OpenFOAM and it will call one library named libparMetisDecomp.so in OpenFOAM. When I try to run YADE, one error occurs that indicates as bellow:

Welcome to Yade bzr2857
Traceback (most recent call last):
  File "/home/tao/YADE/bin/yade-bzr2857", line 118, in <module>
    import yade
  File "/home/tao/YADE/lib/yade-bzr2857/py/yade/__init__.py", line 58, in <module>
    import boot
ImportError: /home/tao/OpenFOAM/OpenFOAM-1.7.1/lib/linux64GccDPOpt/dummy/libparMetisDecomp.so: undefined symbol: _ZN4Foam10FatalErrorE

I'm not sure if it's just a problem with the link or with the library libparMetisDecomp.so.

Thanks a lot for your help.

Cheers,
Tao

1/ You should really try to compile a simple program out of yade first,
with a simple makefile, so you know where problems come from.
This error means (I think) that libparMetisDecomp has other dependencies
(e.g. blas, lapack, or whatever it can be), you would have find this
with a simple "helloOFoamWorld" program.
2/ Don't modify $HOME/trunk/SConstruct or profile.default. They are root
system files that you will (almost) never commit. Create user-defined
profile:
"scons profile='name' CXXFLAGS=... SHCCFLAGS=... ". It has the same
result, except that it will be easier for you and us to understand what
you are doing (e.g. by asking the output of "scons -h", I know what's in
your profile, but I can't tell if you messed up the SConstruct :-)).

Bruno

Hi, Tao:

Linking OpenFOAM libraries are not that simple, your libIcoFoam need additional libraries to operate, I will post additional information about YADE and OpenFOAM coupling shortly.

Feng

Hi Feng,
That's good to hear from you. Thanks a lot.

Cheers,
Tao

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