/*!
\page installation IT++ Installation

\section toc Table of Contents
- \ref requirements
- \ref download
- \ref inst_instructions
  - \ref modularization
  - \ref external_libs
  - \ref optimisation
  - \ref config_status
  - \ref compile_step
  - \ref test_step
  - \ref install_step
- \ref localinst
- \ref msvc


\section requirements IT++ Requirements

IT++ should compile without errors or warnings on most GNU/Linux, BSD and
UNIX systems, and on POSIX based environments for Microsoft Windows like
Cygwin or MinGW with MSYS. It can be also built on Microsoft Windows
NT/2000/XP using Microsoft's Visual C++ .NET (or Express), but our support
for this compiler is limited. For GNU/Linux, FreeBSD, Solaris SunOS, Cygwin
and MinGW we assume that you have at least the following GNU software
installed on your computer:
- <a href="http://www.gnu.org/software/make/">GNU make</a>, version 3.77
or later (check version with <tt>`make --version'</tt> or
<tt>`gmake --version`</tt>)
- <a href="http://gcc.gnu.org/">GCC</a> - GNU Compilers Collection including
C (gcc) and C++ (g++) compilers, version 3.3.x or later (check version with
<tt>`gcc --version'</tt>)
.
In most cases, a Fortran compiler is also required for proper linking of
IT++ with external BLAS and LAPACK libraries. GCC provides g77 (versions
3.x.x) or gfortran (versions 4.x.x) compilers.

We strongly recommend that you use recent stable releases of the GCC, if
possible. We do not actively work on supporting older versions of the GCC,
and they may therefore (without prior notice) become unsupported in future
releases of IT++.

Instead of using GCC, you might try to build and link the IT++ library using
other C/C++/Fortran compilers. For instance, Intel C++ (icpc) and Fortran
(ifc) compilers are known to work well.

To perform tests, two command line programs: \c sed and \c diff are
required. Optionally, you might need a few additional programs, i.e.
<a href="http://www.doxygen.org/">Doxygen</a>,
<a href="http://www.latex-project.org/">LaTeX</a>,
<a href="http://www.radicaleye.com/dvips.html">Dvips</a> and
<a href="http://www.cs.wisc.edu/~ghost/">Ghostscript</a>, to generate the
HTML documentation. The HTML documentation for each release is also
available as separate packages for download, so you do not need to generate
it during the installation.

In order to use all functionality provided by the IT++ library, it is
recommended that you have some external libraries compiled and installed in
your computer. The basic set of them is:
<a href="http://www.netlib.org/blas/">BLAS</a>,
<a href="http://www.netlib.org/lapack/">LAPACK</a> and
<a href="http://www.fftw.org/">FFTW</a> (version 3.0.0 or later).

Instead of NetLib's reference BLAS and LAPACK implementations, some
optimized platform-specific libraries can be used as well, i.e.:
- <a href="http://math-atlas.sourceforge.net/">ATLAS</a> (<em>Automatically
  Tuned Linear Algebra Software</em>) - includes optimised BLAS and a
  limited set of LAPACK routines (version 3.6.0 or later)
- <a href="http://www.intel.com/cd/software/products/asmo-na/eng/perflib/mkl/">MKL</a>
  (<em>Intel Math Kernel Library</em>) - includes all required BLAS,
  LAPACK and FFT routines (version 8.1.1 or later; FFTW not required)
- <a href="http://developer.amd.com/acml.aspx">ACML</a> (<em>AMD Core Math
  Library</em>) - includes BLAS, LAPACK and FFT routines (version
  2.5.3 or later; FFTW not required)

Except the Intel MKL, the above mentioned BLAS/LAPACK implementations
require additional support libraries provided by a Fortran compiler. To use
them with IT++, please make sure that you have the compatible Fortran
compiler installed. For instance, if your system BLAS and LAPACK libraries
were compiled and linked with GNU g77, you should have the same compiler
installed on your system before starting the IT++ configuration process.

It is possible to compile and use IT++ without these external libraries, but
the functionality will be reduced. Therefore, we recommend that you take
some time and effort to provide these external libraries in your system.
Please note that the basic set of them (FFTW, BLAS and LAPACK) is usually
included in most modern Linux distributions.


\section download Obtaining the IT++ Source Codes

IT++ is released under the GNU General Public License (GPL) and hence the
source code of the IT++ library is available for free download. To obtain
the IT++ source code, visit the project pages on SourceForge:
- <a href="http://itpp.sourceforge.net/">http://itpp.sourceforge.net/</a>
.
and download the file named \c itpp-\<VERSION\>.tar.gz or
\c itpp-\<VERSION\>.tar.bz2, where \c \<VERSION\> is the latest release
number, e.g. 4.0.0.


\section inst_instructions General IT++ Configuration and Installation Instructions

Assuming that you have already downloaded the latest IT++ sources, untar
and unpack the sources, and enter the unpacked directory. Depending on the
package type you have downloaded, use the following commands:

\verbatim
% gzip -cd itpp-<VERSION>.tar.gz | tar xf -
% cd itpp-<VERSION>
\endverbatim

\verbatim
% bzip2 -cd itpp-<VERSION>.tar.bz2 | tar xf -
% cd itpp-<VERSION>
\endverbatim

Since version 3.9.0, the IT++ library uses autoconf, automake and libtool
for preparing Makefiles and configuration script, so the compilation
procedure resembles a standard, well-known GNU method, i.e.

\verbatim
% ./configure
% make
\endverbatim

The \c `configure' command can be invoked with additional switches and
options (run <tt>`./configure --help'</tt> to get a full list of them). The
most important are:
- \c `--prefix=PREFIX' - set top installation directory to a certain \c
  PREFIX value. By default it is set to \c `/usr/local', so <tt>`make
  install'</tt> will install appropriate files into \c `/usr/local/include',
  \c `/usr/local/lib`, etc.
- \c `--enable-debug' - build an extra library named \c `libitpp_debug.*'
  using special debugging flags for compiler and linker (disabled by default)
- \c `--enable-exceptions' - enable exceptions handling of run-time errors
  instead of aborting the program (disabled by default)
- \c `--disable-html-doc' - do not generate and install the HTML
  documentation (enabled by default)
- \c `--disable-shared' - do not build the shared version of the library
  (enabled by default for non Windows based platforms)
- \c `--disable-static' - do not build the static version of the library
  (enabled by default for Windows based platforms)
.
Plese note that each \c `--enable-\<OPTION\>' switch can be replaced
with its opposite switch \c `--disable-\<OPTION\>'.


\subsection modularization Modularization

Since version 3.99.0, a modularization of the library has been introduced.
Therefore, several additional switches have been added to the configure
script, which can be used to disable building some of the library
components. Here is a list of them:
- \c `--disable-comm' - do not build the `Communications' module
- \c `--disable-fixed' - do not build the `Fixed-point' module
- \c `--disable-optim' - do not build the `Numerical optimisations' module
- \c `--disable-protocol' - do not include the `Protocols' module
- \c `--disable-signal' - do not build the `Signal processing' module
- \c `--disable-srccode' - do not build the `Source coding' module


\subsection external_libs External Libraries

By default, the \c `configure' script checks for a few external libraries,
which might be used by the IT++ library (cf. \ref requirements).
The detection procedure is as follows:
-# First, the presence of a BLAS library among MKL, ACML, ATLAS and
   NetLib's reference BLAS is checked. If one of the above mentioned can be
   used, \c HAVE_BLAS is defined.
-# Next, some LAPACK library is being searched, but only if BLAS is
   available. Full set of LAPACK routines can be found in the MKL, ACML and
   NetLib's reference LAPACK libraries. Besides, ATLAS contains a subset of
   optimised LAPACK routines, which can be used with NetLib's LAPACK library
   (this is described in the ATLAS documentation). If some LAPACK library
   can be found, \c HAVE_LAPACK is defined.
-# Finally, a set of separate checks for FFT libraries is executed.
   Currently three different libraries providing FFT/IFFT routines can be
   used: MKL, ACML and FFTW. If at least one of them is found, \c HAVE_FFT
   id defined. Besides, one of the following: \c HAVE_FFT_MKL, \c
   HAVE_FFT_ACML or \c HAVE_FFTW3 is defined, respectively.

If some external libraries are installed in a non-standard location in your
system, e.g. MKL in <tt>`/opt/intel/mkl/9.1'</tt>, the \c `configure' script
will not detect them automatically. In such a case, you should use LDFLAGS
and CPPFLAGS environment variables to define additional directories to be
searched for libraries (LDFLAGS) and include files (CPPFLAGS). For instance,
to configure IT++ to link to 32-bit versions of MKL 9.1 external libraries,
which is installed in <tt>`/opt/intel/mkl/9.1'</tt> directory, you should
use the following commands:

\verbatim
% export LDFLAGS="-L/opt/intel/mkl/9.1/lib/32"
% export CPPFLAGS="-I/opt/intel/mkl/9.1/include"
% ./configure
\endverbatim

Instead of CPPFLAGS, one can use \c `--with-fft-include=\<PATH\>' configure
option to set path to header files that provide FFT functionality, i.e. to
<tt>`fftw3.h'</tt>, <tt>`mkl_dft.h'</tt> or <tt>`acml.h'</tt>.

In the case that external libraries have non-standard names, e.g.
<tt>`libblas3.a'</tt> for BLAS, you might specify them to the configure
using \c `--with-\<LIBNAME\>' switches, where \c \<LIBNAME\> is one of the
following: \c `blas', \c `lapack' or \c `fft'. You might use
more than one library names by quoting them, e.g.

\verbatim
% ./configure --with-blas="-latlas -lblas"
\endverbatim

If there is only one library specified, you can use a simplified notation
without the preceding `-l', e.g. \c `--with-fft=fftw3' instead of \c
`--with-fftw=-lfftw3'.

Please refer to the documentation of your external libraries, to find out
what are the correct library names and paths on your architecture, operating
system, etc.

Since 4.0.3 release, the configure script provides a new \c
`--with-zdotu=\<method\>' option. It can be used to force the default
calling convention of BLAS \c `zdotu_' Fortran function. The BLAS libraries
built with g77 compiler do not return the complex result of a function, but
pass it via the first argument of the function. By using \c
`--with-zdotu=void' option, this approach can be forced (g77 compatible). On
the other hand, the libraries built with a newer gfortran compiler return
the complex result like a normal function does, but calling such interface
from C++ is not portable, due to incompatibilities between C++
complex<double> and Fortran's COMPLEX. Therefore in such case a Fortran
wrapper function \c `zdotusub_' can be used (\c `--with-zdotu=zdotusub'),
however it requires a working Fortran compiler. By default, IT++ tries to
guess the proper method based on the detected BLAS implementation. For
instance, the BLAS library provided by Intel MKL works fine with the `void'
method. Eventually, if no Fortran compiler is available and the `void'
method can not be used, the \c zdotu_ BLAS function is not used at all and a
relevant warning message is displayed during the configuration step.

Although it is not recommended, you can intentionally prevent detection of
some external libraries. To do this you should use \c
`--without-\<LIBNAME\>' or \c `--with-\<LIBNAME\>=no', e.g.:

\verbatim
% ./configure --without-blas --without-lapack
\endverbatim


\subsection optimisation Optimisation Flags

It is recommended to set the CXXFLAGS environment variable with some
compiler- and platform-specific optimisation flags, before invoking the \c
`configure' command. Additionally, \c `-DNDEBUG' should be included in the
optimised CXXFLAGS, because it turns off all conditional assertion checks.
This will improve the computation performance of many IT++ functions. For
example, in the case of using the Intel Pentium 4 processor one might employ
the following flags:

\verbatim
% CXXFLAGS="-DNDEBUG -O3 -march=pentium4 -pipe" ./configure
\endverbatim

In the case of Sun's UltraSPARC 64-bit platform and GCC compiler, the flags
might be set as follows:

\verbatim
% export CXXFLAGS="-DNDEBUG -O3 -mcpu=v9 -m64 -pipe"
% ./confiugre
\endverbatim

If CXXFLAGS is not set in the environment, it will be initialised with
the default flags, i.e. <tt>"-DNDEBUG -O3 -pipe"</tt>.


\subsection config_status Configuration Status

When the configuration process is finished, a status message is displayed.
For instance, after having invoked the following configuration command

\verbatim
% ./configure --with-blas="-lblas"
\endverbatim

on a recent Gentoo Linux system with blas-atlas, lapack-atlas and fftw
packages installed, one can observe something like this:

\verbatim
------------------------------------------------------------------------------
itpp-4.0.3 library configuration:
------------------------------------------------------------------------------

Directories:
  - prefix ......... : /usr/local
  - exec_prefix .... : ${prefix}
  - includedir ..... : ${prefix}/include
  - libdir ......... : ${exec_prefix}/lib
  - datarootdir .... : ${prefix}/share
  - docdir ......... : ${datarootdir}/doc/${PACKAGE_TARNAME}

Switches:
  - debug .......... : no
  - exceptions ..... : no
  - html-doc ....... : yes
  - shared ......... : yes
  - static ......... : no
  - explicit deps .. : no
  - zdotu .......... : zdotusub

Documentation tools:
  - doxygen ........ : yes
  - latex .......... : yes
  - dvips .......... : yes
  - ghostscript .... : yes

Testing tools:
  - diff ........... : yes

Optional modules:
  - comm ........... : yes
  - fixed .......... : yes
  - optim .......... : yes
  - protocol ....... : yes
  - signal ......... : yes
  - srccode ........ : yes

External libs:
  - BLAS ........... : yes
    * MKL .......... : no
    * ACML ......... : no
    * ATLAS ........ : yes
  - LAPACK ......... : yes
  - FFT ............ : yes
    * MKL .......... : no
    * ACML ......... : no
    * FFTW ......... : yes

Compiler/linker flags/libs/defs:
  - CXX ............ : g++
  - F77 ............ : gfortran
  - CXXFLAGS ....... : -DNDEBUG -O3 -pipe
  - CXXFLAGS_DEBUG . :
  - CPPFLAGS ....... :
  - LDFLAGS ........ :
  - LIBS ........... : -lfftw3 -llapack -lblas

------------------------------------------------------------------------------
Now type 'make && make install' to build and install itpp-4.0.3 library
------------------------------------------------------------------------------

\endverbatim


\subsection compile_step Compilation

Now, it is time for compiling and linking the IT++ library. To do so, please
simply run the following command:

\verbatim
% make
\endverbatim

IT++ should compile without any errors or warnings. If this is not the case,
please report the problem on the IT++ Help forum at SourceForge. Please
include information about your OS, compiler version, external libraries and
their versions, etc.


\subsection test_step Testing the Compiled Library

It is recommended that you check if your library has been compiled and linked
properly and works as expected. To do so, you should execute the testing
process:

\verbatim
% make check
\endverbatim

As a result, you should obtain a similar report:

\verbatim
------------------------------------------------------------------------------
Test `array_test' PASSED.
------------------------------------------------------------------------------
Test `bessel_test' PASSED.
------------------------------------------------------------------------------

[...]

------------------------------------------------------------------------------
Test `window_test' PASSED.
------------------------------------------------------------------------------
Test `histogram_test' PASSED.
------------------------------------------------------------------------------
Test `stat_test' PASSED.
------------------------------------------------------------------------------
\endverbatim

Check if all the executed tests PASSED. If not, please report the problem on
the IT++ Help forum.


\subsection install_step Installation

Finally, you should install the compiled and linked library, include files
and HTML documentation (optionally) by typing:

\verbatim
% make install
\endverbatim

Depending on the \c PREFIX settings during configuration, you might need
the root (administrator) access to perform this step.

Eventually, you might invoke the following command

\verbatim
% make clean
\endverbatim

to remove all files created during compilation process, or even

\verbatim
% make distclean
\endverbatim

to remove all files generated by the \c `configure' script.


\section localinst How To Set Up a Local, Dual-config IT++ Installation without Being Root

This section presents a walkthrough of how to easily set up an IT++
environment without being root (all files are installed locally). The
installation results in two parallel versions of the IT++ library, one
version with debugging features enabled (this is slow in general but
can be valuable during the development phase) and one version which is
complied with maximum optimization. When compiling executables, one
can then easily generate two versions of a program: one for debugging
and one for maximum runtime efficiency. See the Makefile below for an
example.

The philosophy behind this installation is:
- to locally compile and install all required external libraries (LAPACK,
  BLAS and FFTW) from sources; this is because not all systems
  provide these libraries as ready to use binaries
- to install two parallel IT++ libraries: one optimized and one for
  debugging
- to use static linking only (this gives larger executables but is sometimes
  useful for debugging purposes)

The source code will reside in the directories itpp-external-3.0.0 and
itpp-4.0.0. The libraries will be created in the directories
it++external-3.0.0 and it++4.0.0.

The installation procedure goes as follows (\c $HOME can be replaced by any
directory where you have write access):
<ol>
<li> Download itpp-external-3.0.0.tar.bz2 and itpp-4.0.0.tar.bz2. Save
them in your \c $HOME directory, and unpack them:
\verbatim
% cd $HOME
% tar jzf itpp-external-3.0.0.tar.bz2
% tar jzf itpp-4.0.0.tar.bz2
\endverbatim
</li>

<li> Compile and install the external libs
\verbatim
% cd $HOME/itpp-external-3.0.0
% make distclean
% ./configure --prefix=$HOME/it++external-3.0.0 --disable-shared --enable-static
% make && make install
\endverbatim
</li>

<li> Compile and install the optimized and debugging IT++ libraries:
\verbatim
% export LDFLAGS=-L$HOME/it++external-3.0.0/lib
% export CPPFLAGS=-I$HOME/it++external-3.0.0/include
% cd $HOME/itpp-4.0.0
% make distclean
% ./configure --disable-shared --enable-static --enable-debug --prefix=$HOME/it++4.0.0
% make && make check && make install
\endverbatim
</li>

<li> Go to a temporary directory, and create the following program \c
example.cpp:
\code
#include <itpp/itsignal.h>

using namespace itpp;
using namespace std;

int main()
{
  for (int i = 0; i < 10; i++) {
    mat X = randn(500, 500);
    mat Z = chol(X * X.transpose());
    cout << Z(0, 0) << endl;
  }

  for (int i = 0; i < 10; i++) {
    cvec a = fft(randn_c(10000));
    cout << a(5) << endl;
  }

  it_assert_debug(1 == 0, "Debugging is on!");
}
\endcode

Also, in the same directory, create the following \c Makefile:
\verbatim
FLAGS_DEBUG = `$(HOME)/it++4.0.0/bin/itpp-config --debug --cflags`
FLAGS_OPT   = `$(HOME)/it++4.0.0/bin/itpp-config --cflags`

LIBS_DEBUG  = `$(HOME)/it++4.0.0/bin/itpp-config --debug --static --libs`
LIBS_OPT    = `$(HOME)/it++4.0.0/bin/itpp-config --static --libs`

example: example.cpp
	g++ $(FLAGS_DEBUG) example.cpp -o example_debug  $(LIBS_DEBUG)
	g++ $(FLAGS_OPT) example.cpp -o example_opt  $(LIBS_OPT)
\endverbatim

This \c Makefile produces two programs: \c example_opt and \c example_debug.
The former is optimized for performance but offers no debugging or
assertions. The latter includes debugging info and is compiled with all
assertions enabled (this generally gives "safe" but slow code).

Run \c make and try the programs \c example_opt and \c example_debug. If
this works the library is ready to use. (The program \c example_debug should
exit with an assertion error.) </li>

<li> If you want to conserve disk space, clean up all temporary files:
\verbatim
% cd $HOME/itpp-external-3.0.0
% make distclean
% cd $HOME/itpp-4.0.0
% make distclean
\endverbatim

To conserve even more diskspace (remove all sources) then do
\verbatim
% rm -rf $HOME/itpp-external-3.0.0
% rm -rf $HOME/itpp-4.0.0
\endverbatim
</li>
</ol>

Note: the \c make \c distclean commands in some steps may result in an error
message; just ignore this. But the command is recommended because it
guarantees that you start with a clean directory, in the event you would
repeat the installation procedure.


\section msvc IT++ Compilation and Installation using Microsoft Visual C++

It is possible to compile and link the IT++ library using the
<a href="http://msdn.microsoft.com/visualc/">Microsoft Visual C++ .NET</a>
(or Express) compiler and either
<a href="http://www.intel.com/cd/software/products/asmo-na/eng/perflib/mkl/">
Intel Math Kernel Library (MKL)</a> or
<a href="http://developer.amd.com/acml.aspx">AMD Core Math Library (ACML)</a>.

First, you need to install ACML or MKL in your system. If you decide to use
ACML, please download the library built with PGI compiler for Windows, e.g.
<tt>acml3.6.0-32-pgi.exe</tt> file for 32-bit systems. Please follow the
default installation steps of the ACML or MKL installer. After waiting a few
dozens of seconds you should have the chosen external libraries installed on
your computer. Finally, you need to set up a few environment variables, so
the library and include files can be found during compilation and linking of
the IT++ library. These environment variables are as follows:
- \c INCLUDE - specifies the path to header files, e.g.
  <tt>INCLUDE="C:\\Program Files\\AMD\\acml3.6.0\\pgi32\\include"</tt> for
  ACML 3.6.0 or
  <tt>INCLUDE="C:\\Program Files\\Intel\\MKL\\9.1\\include"</tt> for MKL 9.1
- \c LIB - specifies the path to library files, e.g.
  <tt>LIB="C:\\Program Files\\AMD\\acml3.6.0\\pgi32\\lib"</tt> or
  <tt>LIB="C:\\Program Files\\Intel\\MKL\\9.1\\ia32\\lib"</tt>
- \c PATH - specifies the runtime path to DLL libraries, e.g.
  <tt>PATH="C:\\Program Files\\AMD\\acml3.6.0\\pgi32\\lib"</tt> or
  <tt>PATH="C:\\Program Files\\Intel\\MKL\\9.1\\ia32\\bin"</tt>
.
Please note that the \c PATH environment variable is usually already defined,
so you should just append the runtime path to DLL libraries to the existing
\c PATH, using a semicolon as a separation character.

The next step is to compile and link the IT++ library. Assuming that you
have already downloaded and unpacked the IT++ package, you should find
the <tt>itpp_acml.vcproj</tt> and <tt>itpp_mkl.vcproj</tt> MSVC++ project
files in the <tt>win32</tt> directory. Depending on the installed external
library (ACML or MKL), open one of these project files in the MSVC++ IDE
environment. There are two default targets prepared for compilation and
linking: <tt>Debug</tt> and <tt>Release</tt>. The former can be used to
compile a non-optimised version of the library for debugging purposes,
named <tt>itpp_debug.lib</tt>, whereas the latter one should produce an
optimised library named <tt>itpp.lib</tt>, which is also used by test
programs. Both libraries will be created in <tt>win32\\lib</tt> directory.
IT++ should compile and link without any warnings or errors.

Last but not least, test programs can be compiled and linked to IT++ with
MKL or ACML by using the project files included
in <tt>win32\\itpp_mkl_tests</tt> or <tt>win32\\itpp_acml_tests</tt>
respectively. The resulting executable test files should be created
in <tt>win32\\bin</tt> directory. Currently there is no automated method for
comparing the output of these test programs with the reference files
(<tt>*.ref</tt>) located in <tt>tests</tt> directory.

To learn how to set up your own project for linking with the IT++ library
and ACML or MKL, please read the following manual: \ref msvc_linking.

*/