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IT++ Installation

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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:

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: sed and diff are required. Optionally, you might need a few additional programs, i.e. Doxygen, LaTeX, Dvips and Ghostscript, 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: BLAS, LAPACK and FFTW (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.:

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.

Obtaining the IT++ Source Codes

IT++ is released under the terms of 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:

and download the file named itpp-<VERSION>.tar.gz or itpp-<VERSION>.tar.bz2, where <VERSION> is the latest release number, e.g. 4.0.0.

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:

% gzip -cd itpp-<VERSION>.tar.gz | tar xf -
% cd itpp-<VERSION>
% bzip2 -cd itpp-<VERSION>.tar.bz2 | tar xf -
% cd itpp-<VERSION>

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.

% ./configure
% make

The `configure' command can be invoked with additional switches and options (run `./configure --help' to get a full list of them). The most important are:

Plese note that each `--enable-<OPTION>' switch can be replaced with its opposite switch `--disable-<OPTION>'.


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:

External Libraries

By default, the `configure' script checks for a few external libraries, which might be used by the IT++ library (cf. IT++ Requirements). The detection procedure is as follows:

  1. 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, HAVE_BLAS is defined.
  2. 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, HAVE_LAPACK is defined.
  3. 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, HAVE_FFT id defined. Besides, one of the following: HAVE_FFT_MKL, HAVE_FFT_ACML or HAVE_FFTW3 is defined, respectively.

If some external libraries are installed in a non-standard location in your system, e.g. MKL in `/opt/intel/mkl/9.1', the `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 `/opt/intel/mkl/9.1' directory, you should use the following commands:

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

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

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

% ./configure --with-blas="-latlas -lblas"

If there is only one library specified, you can use a simplified notation without the preceding `-l', e.g. `--with-fft=fftw3' instead of `--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 `--with-zdotu=<method>' option. It can be used to force the default calling convention of BLAS `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 `--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 `zdotusub_' can be used (`--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 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 `--without-<LIBNAME>' or `--with-<LIBNAME>=no', e.g.:

% ./configure --without-blas --without-lapack

Optimisation Flags

It is recommended to set the CXXFLAGS environment variable with some compiler- and platform-specific optimisation flags, before invoking the `configure' command. Additionally, `-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:

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

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

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

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

Configuration Status

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

% ./configure --with-blas="-lblas"

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

itpp-4.0.3 library configuration:

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

  - 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
  - CPPFLAGS ....... :
  - LDFLAGS ........ :
  - LIBS ........... : -lfftw3 -llapack -lblas

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


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

% make

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.

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:

% make check

As a result, you should obtain a similar report:

Test `array_test' PASSED.
Test `bessel_test' PASSED.


Test `window_test' PASSED.
Test `histogram_test' PASSED.
Test `stat_test' PASSED.

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


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

% make install

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

Eventually, you might invoke the following command

% make clean

to remove all files created during compilation process, or even

% make distclean

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

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:

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 ($HOME can be replaced by any directory where you have write access):

  1. Download itpp-external-3.0.0.tar.bz2 and itpp-4.0.0.tar.bz2. Save them in your $HOME directory, and unpack them:

    % cd $HOME
    % tar jzf itpp-external-3.0.0.tar.bz2
    % tar jzf itpp-4.0.0.tar.bz2

  2. Compile and install the external libs

    % cd $HOME/itpp-external-3.0.0
    % make distclean
    % ./configure --prefix=$HOME/it++external-3.0.0 --disable-shared --enable-static
    % make && make install

  3. Compile and install the optimized and debugging IT++ libraries:

    % 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

  4. Go to a temporary directory, and create the following program example.cpp:

    #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!");

    Also, in the same directory, create the following Makefile:

    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)

    This Makefile produces two programs: example_opt and 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 make and try the programs example_opt and example_debug. If this works the library is ready to use. (The program example_debug should exit with an assertion error.)

  5. If you want to conserve disk space, clean up all temporary files:

    % cd $HOME/itpp-external-3.0.0
    % make distclean
    % cd $HOME/itpp-4.0.0
    % make distclean

    To conserve even more diskspace (remove all sources) then do

    % rm -rf $HOME/itpp-external-3.0.0
    % rm -rf $HOME/itpp-4.0.0

Note: the make 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.

IT++ Compilation and Installation using Microsoft Visual C++

It is possible to compile and link the IT++ library using the Microsoft Visual C++ .NET (or Express) compiler and either Intel Math Kernel Library (MKL) or AMD Core Math Library (ACML).

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. acml3.6.0-32-pgi.exe 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:

Please note that the PATH environment variable is usually already defined, so you should just append the runtime path to DLL libraries to the existing 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 itpp_acml.vcproj and itpp_mkl.vcproj MSVC++ project files in the win32 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: Debug and Release. The former can be used to compile a non-optimised version of the library for debugging purposes, named itpp_debug.lib, whereas the latter one should produce an optimised library named itpp.lib, which is also used by test programs. Both libraries will be created in win32\lib 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 win32\itpp_mkl_tests or win32\itpp_acml_tests respectively. The resulting executable test files should be created in win32\bin directory. Currently there is no automated method for comparing the output of these test programs with the reference files (*.ref) located in tests 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: Linking your own programs with IT++ using MSVC++.

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