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<div class="section">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="mpi.getting_started"></a><a class="link" href="getting_started.html" title="Getting started">Getting started</a>
</h2></div></div></div>
<div class="toc"><dl class="toc">
<dt><span class="section"><a href="getting_started.html#mpi.getting_started.implementation">MPI Implementation</a></span></dt>
<dt><span class="section"><a href="getting_started.html#mpi.getting_started.config">Configure and Build</a></span></dt>
<dt><span class="section"><a href="getting_started.html#mpi.getting_started.using">Using Boost.MPI</a></span></dt>
</dl></div>
<p>
Getting started with Boost.MPI requires a working MPI implementation, a recent
version of Boost, and some configuration information.
</p>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="mpi.getting_started.implementation"></a><a class="link" href="getting_started.html#mpi.getting_started.implementation" title="MPI Implementation">MPI Implementation</a>
</h3></div></div></div>
<p>
To get started with Boost.MPI, you will first need a working MPI implementation.
There are many conforming <a href="http://www-unix.mcs.anl.gov/mpi/implementations.html" target="_top">MPI
implementations</a> available. Boost.MPI should work with any of the
implementations, although it has only been tested extensively with:
</p>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<a href="http://www.open-mpi.org" target="_top">Open MPI</a>
</li>
<li class="listitem">
<a href="http://www-unix.mcs.anl.gov/mpi/mpich/" target="_top">MPICH2</a>
</li>
<li class="listitem">
<a href="https://software.intel.com/en-us/intel-mpi-library" target="_top">Intel
MPI</a>
</li>
</ul></div>
<p>
You can test your implementation using the following simple program, which
passes a message from one processor to another. Each processor prints a message
to standard output.
</p>
<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">mpi</span><span class="special">.</span><span class="identifier">h</span><span class="special">></span>
<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">iostream</span><span class="special">></span>
<span class="keyword">int</span> <span class="identifier">main</span><span class="special">(</span><span class="keyword">int</span> <span class="identifier">argc</span><span class="special">,</span> <span class="keyword">char</span><span class="special">*</span> <span class="identifier">argv</span><span class="special">[])</span>
<span class="special">{</span>
<span class="identifier">MPI_Init</span><span class="special">(&</span><span class="identifier">argc</span><span class="special">,</span> <span class="special">&</span><span class="identifier">argv</span><span class="special">);</span>
<span class="keyword">int</span> <span class="identifier">rank</span><span class="special">;</span>
<span class="identifier">MPI_Comm_rank</span><span class="special">(</span><span class="identifier">MPI_COMM_WORLD</span><span class="special">,</span> <span class="special">&</span><span class="identifier">rank</span><span class="special">);</span>
<span class="keyword">if</span> <span class="special">(</span><span class="identifier">rank</span> <span class="special">==</span> <span class="number">0</span><span class="special">)</span> <span class="special">{</span>
<span class="keyword">int</span> <span class="identifier">value</span> <span class="special">=</span> <span class="number">17</span><span class="special">;</span>
<span class="keyword">int</span> <span class="identifier">result</span> <span class="special">=</span> <span class="identifier">MPI_Send</span><span class="special">(&</span><span class="identifier">value</span><span class="special">,</span> <span class="number">1</span><span class="special">,</span> <span class="identifier">MPI_INT</span><span class="special">,</span> <span class="number">1</span><span class="special">,</span> <span class="number">0</span><span class="special">,</span> <span class="identifier">MPI_COMM_WORLD</span><span class="special">);</span>
<span class="keyword">if</span> <span class="special">(</span><span class="identifier">result</span> <span class="special">==</span> <span class="identifier">MPI_SUCCESS</span><span class="special">)</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"Rank 0 OK!"</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span>
<span class="special">}</span> <span class="keyword">else</span> <span class="keyword">if</span> <span class="special">(</span><span class="identifier">rank</span> <span class="special">==</span> <span class="number">1</span><span class="special">)</span> <span class="special">{</span>
<span class="keyword">int</span> <span class="identifier">value</span><span class="special">;</span>
<span class="keyword">int</span> <span class="identifier">result</span> <span class="special">=</span> <span class="identifier">MPI_Recv</span><span class="special">(&</span><span class="identifier">value</span><span class="special">,</span> <span class="number">1</span><span class="special">,</span> <span class="identifier">MPI_INT</span><span class="special">,</span> <span class="number">0</span><span class="special">,</span> <span class="number">0</span><span class="special">,</span> <span class="identifier">MPI_COMM_WORLD</span><span class="special">,</span>
<span class="identifier">MPI_STATUS_IGNORE</span><span class="special">);</span>
<span class="keyword">if</span> <span class="special">(</span><span class="identifier">result</span> <span class="special">==</span> <span class="identifier">MPI_SUCCESS</span> <span class="special">&&</span> <span class="identifier">value</span> <span class="special">==</span> <span class="number">17</span><span class="special">)</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"Rank 1 OK!"</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span>
<span class="special">}</span>
<span class="identifier">MPI_Finalize</span><span class="special">();</span>
<span class="keyword">return</span> <span class="number">0</span><span class="special">;</span>
<span class="special">}</span>
</pre>
<p>
You should compile and run this program on two processors. To do this, consult
the documentation for your MPI implementation. With <a href="http://www.open-mpi.org" target="_top">OpenMPI</a>,
for instance, you compile with the <code class="computeroutput"><span class="identifier">mpiCC</span></code>
or <code class="computeroutput"><span class="identifier">mpic</span><span class="special">++</span></code>
compiler, boot the LAM/MPI daemon, and run your program via <code class="computeroutput"><span class="identifier">mpirun</span></code>. For instance, if your program is
called <code class="computeroutput"><span class="identifier">mpi</span><span class="special">-</span><span class="identifier">test</span><span class="special">.</span><span class="identifier">cpp</span></code>,
use the following commands:
</p>
<pre class="programlisting">mpiCC -o mpi-test mpi-test.cpp
lamboot
mpirun -np 2 ./mpi-test
lamhalt
</pre>
<p>
When you run this program, you will see both <code class="computeroutput"><span class="identifier">Rank</span>
<span class="number">0</span> <span class="identifier">OK</span><span class="special">!</span></code> and <code class="computeroutput"><span class="identifier">Rank</span>
<span class="number">1</span> <span class="identifier">OK</span><span class="special">!</span></code> printed to the screen. However, they may
be printed in any order and may even overlap each other. The following output
is perfectly legitimate for this MPI program:
</p>
<pre class="programlisting">Rank Rank 1 OK!
0 OK!
</pre>
<p>
If your output looks something like the above, your MPI implementation appears
to be working with a C++ compiler and we're ready to move on.
</p>
</div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="mpi.getting_started.config"></a><a class="link" href="getting_started.html#mpi.getting_started.config" title="Configure and Build">Configure and Build</a>
</h3></div></div></div>
<div class="toc"><dl class="toc">
<dt><span class="section"><a href="getting_started.html#mpi.getting_started.config.bootstrap">Bootstrap</a></span></dt>
<dt><span class="section"><a href="getting_started.html#mpi.getting_started.config.setup">Setting up your MPI
Implementation</a></span></dt>
<dt><span class="section"><a href="getting_started.html#mpi.getting_started.config.build">Build</a></span></dt>
<dt><span class="section"><a href="getting_started.html#mpi.getting_started.config.tests">Tests</a></span></dt>
<dt><span class="section"><a href="getting_started.html#mpi.getting_started.config.installation">Installation</a></span></dt>
</dl></div>
<p>
As the rest of Boost, Boost.MPI uses version 2 of the <a href="http://www.boost.org/doc/html/bbv2.html" target="_top">Boost.Build</a>
system for configuring and building the library binary.
</p>
<p>
Please refer to the general Boost installation instructions for <a href="http://www.boost.org/doc/libs/release/more/getting_started/unix-variants.html#prepare-to-use-a-boost-library-binary" target="_top">Unix
Variant</a> (including Unix, Linux and MacOS) or <a href="http://www.boost.org/doc/libs/1_58_0/more/getting_started/windows.html#prepare-to-use-a-boost-library-binary" target="_top">Windows</a>.
The simplified build instructions should apply on most platforms with a few
specific modifications described below.
</p>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="mpi.getting_started.config.bootstrap"></a><a class="link" href="getting_started.html#mpi.getting_started.config.bootstrap" title="Bootstrap">Bootstrap</a>
</h4></div></div></div>
<p>
As explained in the boost installation instructions, running the bootstrap
(<code class="computeroutput"><span class="special">./</span><span class="identifier">bootstrap</span><span class="special">.</span><span class="identifier">sh</span></code> for
unix variants or <code class="computeroutput"><span class="identifier">bootstrap</span><span class="special">.</span><span class="identifier">bat</span></code>
for Windows) from the boost root directory will produce a 'project-config.jam`
file. You need to edit that file and add the following line:
</p>
<pre class="programlisting"><span class="keyword">using</span> <span class="identifier">mpi</span> <span class="special">;</span>
</pre>
<p>
Alternatively, you can explicitly provide the list of Boost libraries you
want to build. Please refer to the <code class="computeroutput"><span class="special">--</span><span class="identifier">help</span></code> option of the <code class="computeroutput"><span class="identifier">bootstrap</span></code>
script.
</p>
</div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="mpi.getting_started.config.setup"></a><a class="link" href="getting_started.html#mpi.getting_started.config.setup" title="Setting up your MPI Implementation">Setting up your MPI
Implementation</a>
</h4></div></div></div>
<div class="toc"><dl class="toc"><dt><span class="section"><a href="getting_started.html#mpi.getting_started.config.setup.troubleshooting">Trouble
shooting</a></span></dt></dl></div>
<p>
First, you need to scan the <code class="literal">include/boost/mpi/config.hpp</code>
file and check if some settings need to be modified for your MPI implementation
or preferences.
</p>
<p>
In particular, the <code class="computeroutput"><a class="link" href="../BOOST_MPI_HOMOGENEOUS.html" title="Macro BOOST_MPI_HOMOGENEOUS">BOOST_MPI_HOMOGENEOUS</a></code>
macro, that you will need to comment out if you plan to run on a heterogeneous
set of machines. See the <a class="link" href="tutorial.html#mpi.tutorial.performance_optimizations.homogeneous_machines" title="Homogeneous Machines">optimization</a>
notes below.
</p>
<p>
Most MPI implementations require specific compilation and link options.
In order to mask theses details to the user, most MPI implementations provide
wrappers which silently pass those options to the compiler.
</p>
<p>
Depending on your MPI implementation, some work might be needed to tell
Boost which specific MPI option to use. This is done through the <code class="computeroutput"><span class="keyword">using</span> <span class="identifier">mpi</span> <span class="special">;</span></code> directive in the <code class="computeroutput"><span class="identifier">project</span><span class="special">-</span><span class="identifier">config</span><span class="special">.</span><span class="identifier">jam</span></code>
file those general form is (do not forget to leave spaces around <span class="bold"><strong>:</strong></span> and before <span class="bold"><strong>;</strong></span>):
</p>
<pre class="programlisting">using mpi
: [<MPI compiler wrapper>]
: [<compilation and link options>]
: [<mpi runner>] ;
</pre>
<p>
Depending on your installation and MPI distribution, the build system might
be able to find all the required informations and you just need to specify:
</p>
<pre class="programlisting">using mpi ;
</pre>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="mpi.getting_started.config.setup.troubleshooting"></a><a class="link" href="getting_started.html#mpi.getting_started.config.setup.troubleshooting" title="Trouble shooting">Trouble
shooting</a>
</h5></div></div></div>
<p>
Most of the time, specially with production HPC clusters, some work will
need to be done.
</p>
<p>
Here is a list of the most common issues and suggestions on how to fix
those.
</p>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
<span class="bold"><strong>Your wrapper is not in your path or does ot
have a standard name </strong></span>
</li></ul></div>
<p>
You will need to tell the build system how to call it using the first
parameter:
</p>
<pre class="programlisting">using mpi : /opt/mpi/bullxmpi/1.2.8.3/bin/mpicc ;
</pre>
<div class="warning"><table border="0" summary="Warning">
<tr>
<td rowspan="2" align="center" valign="top" width="25"><img alt="[Warning]" src="../../../doc/src/images/warning.png"></td>
<th align="left">Warning</th>
</tr>
<tr><td align="left" valign="top"><p>
Boost.MPI only uses the C interface, so specifying the C wrapper should
be enough. But some implementations will insist on importing the C++
bindings.
</p></td></tr>
</table></div>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
<span class="bold"><strong>Your wrapper is really eccentric or does not
exist</strong></span>
</li></ul></div>
<p>
With some implementations, or with some specific integration<a href="#ftn.mpi.getting_started.config.setup.troubleshooting.f0" class="footnote" name="mpi.getting_started.config.setup.troubleshooting.f0"><sup class="footnote">[10]</sup></a> you will need to provide the compilation and link options
through de second parameter using 'jam' directives. The following type
configuration used to be required for some specific Intel MPI implementation
(in such a case, the name of the wrapper can be left blank):
</p>
<pre class="programlisting">using mpi : mpiicc :
<library-path>/softs/intel/impi/5.0.1.035/intel64/lib
<library-path>/softs/intel/impi/5.0.1.035/intel64/lib/release_mt
<include>/softs/intel/impi/5.0.1.035/intel64/include
<find-shared-library>mpifort
<find-shared-library>mpi_mt
<find-shared-library>mpigi
<find-shared-library>dl
<find-shared-library>rt ;
</pre>
<p>
As a convenience, MPI wrappers usually have an option that provides the
required informations, which usually starts with <code class="computeroutput"><span class="special">--</span><span class="identifier">show</span></code>. You can use those to find out
the requested jam directive:
</p>
<pre class="programlisting">$ mpiicc -show
icc -I/softs/.../include ... -L/softs/.../lib ... -Xlinker -rpath -Xlinker /softs/.../lib .... -lmpi -ldl -lrt -lpthread
$
</pre>
<pre class="programlisting">$ mpicc --showme
icc -I/opt/.../include -pthread -L/opt/.../lib -lmpi -ldl -lm -lnuma -Wl,--export-dynamic -lrt -lnsl -lutil -lm -ldl
$ mpicc --showme:compile
-I/opt/mpi/bullxmpi/1.2.8.3/include -pthread
$ mpicc --showme:link
-pthread -L/opt/.../lib -lmpi -ldl -lm -lnuma -Wl,--export-dynamic -lrt -lnsl -lutil -lm -ldl
$
</pre>
<p>
To see the results of MPI auto-detection, pass <code class="computeroutput"><span class="special">--</span><span class="identifier">debug</span><span class="special">-</span><span class="identifier">configuration</span></code> on the bjam command line.
</p>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
<span class="bold"><strong>The launch syntax cannot be detected</strong></span>
</li></ul></div>
<div class="note"><table border="0" summary="Note">
<tr>
<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../doc/src/images/note.png"></td>
<th align="left">Note</th>
</tr>
<tr><td align="left" valign="top"><p>
This is only used when <a class="link" href="getting_started.html#mpi.getting_started.config.tests" title="Tests">running
the tests</a>.
</p></td></tr>
</table></div>
<p>
If you need to use a special command to launch an MPI program, you will
need to specify it through the third parameter of the <code class="computeroutput"><span class="keyword">using</span>
<span class="identifier">mpi</span></code> directive.
</p>
<p>
So, assuming you launch the <code class="computeroutput"><span class="identifier">all_gather_test</span></code>
program with:
</p>
<pre class="programlisting">$mpiexec.hydra -np 4 all_gather_test
</pre>
<p>
The directive will look like:
</p>
<pre class="programlisting">using mpi : mpiicc :
[<compilation and link options>]
: mpiexec.hydra -n ;
</pre>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="mpi.getting_started.config.build"></a><a class="link" href="getting_started.html#mpi.getting_started.config.build" title="Build">Build</a>
</h4></div></div></div>
<p>
To build the whole Boost distribution:
</p>
<pre class="programlisting">$cd <boost distribution>
$./b2
</pre>
<p>
To build the Boost.MPI library and dependancies:
</p>
<pre class="programlisting">$cd <boost distribution>/lib/mpi/build
$../../../b2
</pre>
</div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="mpi.getting_started.config.tests"></a><a class="link" href="getting_started.html#mpi.getting_started.config.tests" title="Tests">Tests</a>
</h4></div></div></div>
<p>
You can run the regression tests with:
</p>
<pre class="programlisting">$cd <boost distribution>/lib/mpi/test
$../../../b2
</pre>
</div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="mpi.getting_started.config.installation"></a><a class="link" href="getting_started.html#mpi.getting_started.config.installation" title="Installation">Installation</a>
</h4></div></div></div>
<p>
To install the whole Boost distribution:
</p>
<pre class="programlisting">$cd <boost distribution>
$./b2 install
</pre>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="mpi.getting_started.using"></a><a class="link" href="getting_started.html#mpi.getting_started.using" title="Using Boost.MPI">Using Boost.MPI</a>
</h3></div></div></div>
<p>
To build applications based on Boost.MPI, compile and link them as you normally
would for MPI programs, but remember to link against the <code class="computeroutput"><span class="identifier">boost_mpi</span></code>
and <code class="computeroutput"><span class="identifier">boost_serialization</span></code> libraries,
e.g.,
</p>
<pre class="programlisting">mpic++ -I/path/to/boost/mpi my_application.cpp -Llibdir \
-lboost_mpi -lboost_serialization
</pre>
<p>
If you plan to use the <a class="link" href="python.html" title="Python Bindings">Python bindings</a>
for Boost.MPI in conjunction with the C++ Boost.MPI, you will also need to
link against the boost_mpi_python library, e.g., by adding <code class="computeroutput"><span class="special">-</span><span class="identifier">lboost_mpi_python</span><span class="special">-</span><span class="identifier">gcc</span></code> to
your link command. This step will only be necessary if you intend to <a class="link" href="python.html#mpi.python.user_data" title="Transmitting User-Defined Data">register C++ types</a> or use the <a class="link" href="python.html#mpi.python.skeleton_content" title="Skeleton/Content Mechanism">skeleton/content mechanism</a> from
within Python.
</p>
</div>
<div class="footnotes">
<br><hr style="width:100; text-align:left;margin-left: 0">
<div id="ftn.mpi.getting_started.config.setup.troubleshooting.f0" class="footnote"><p><a href="#mpi.getting_started.config.setup.troubleshooting.f0" class="para"><sup class="para">[10] </sup></a>
Some HPC cluster will insist that the users uss theirs own in house
interface to the MPI system.
</p></div>
</div>
</div>
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
<td align="left"></td>
<td align="right"><div class="copyright-footer">Copyright © 2005-2007 Douglas Gregor,
Matthias Troyer, Trustees of Indiana University<p>
Distributed under the Boost Software License, Version 1.0. (See accompanying
file LICENSE_1_0.txt or copy at <ulink url="http://www.boost.org/LICENSE_1_0.txt">
http://www.boost.org/LICENSE_1_0.txt </ulink>)
</p>
</div></td>
</tr></table>
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