INSTALL.md

Installation Notes

The library is written in Fortran. It is Fortran-90/95-compliant. Fortran 77 compilers are no longer supported. This includes the f2c translator as well.

Requirements

The library requires a Fortran 90/95 compiler, BLAS, and LAPACK. The following compilers and BLAS/LAPACK implementations are tested under Linux. Other operating systems, which are supported by CMAKE, should work as well.

Tested Fortran compilers:

• GNU gfortran 4.8.5, 5.4, 7.3, 8.3, 9.2, 9.3
• Intel ifort 18.0.1
• IBM XLF 16.1.1

Tested BLAS/LAPACK implementations:

• Reference BLAS/LAPACK, http://www.netlib.org/lapack
• OpenBLAS, https://www.openblas.net
• FlexiBLAS, https://www.mpi-magdeburg.mpg.de/projects/ flexiblas
• Intel MKL, https://software.intel.com/en-us/mkl
• IBM ESSL (Missing LAPACK routines are automatically added.), https://www.ibm.com/support/knowledgecenter/en/SSFHY8

The compilation requires at least CMAKE 3.1.

Configuration and Installation

CMAKE is used to configure the source code. Out-of-source builds are prefered.

The default installation of qrupdate-ng is done by

mkdir -p build && cd build
cmake ../ -DCMAKE_INSTALL_PREFIX=/your/installation/path/
make
make install

The installation can adjusted with the help of the CMAKE options. Beside the standard options of CMAKE, the following ones are supported:

Option	Description
-DEBUG=OFF/ON	Enable the debug build.
-DHOSTOPT=OFF/ON	Enable host specific compiler flags.
-DFORTRAN_BOUND_CHECK=OFF/ON	Enable the runtime bound checker.
-DFORTRAN_SANITIZE=OFF/ON	Enable the runtime sanitizer.
-DBUILD_SHARED_LIBS=ON/OFF	Enable building of shared libraries.

The FORTRAN_BOUND_CHECK option is only supported for gfortran and ifort compilers. The FORTRAN_SANITIZE option can only be used with the gfortran compiler. If the host optimizations are enabled, the build might not be portable to other computers.

The qrupdate-ng code includes a testsuite which can be executed by make test.

Selecting individual BLAS and LAPACK libraries

By default CMAKE uses the first BLAS and LAPACK library it finds on the system. If a special selection is required, one can either specifiy the BLA_VENDOR vendor option of CMAKE's FindBLAS.cmake module or specify the BLAS and LAPACK libraries completly on ones own.

Possible values for the BLA_VENDOR options can be found in the help of the FindBLAS.cmake module and can be obtained by cmake --help-module FindBLAS.

A custom BLAS and LAPACK library can be specified by setting the BLAS_LIBRRARIES and LAPACK_LIBRARIES variables. The variable contain a semicolon separated list of libraries that are required to provide the BLAS and LAPACK functionality. If a libraries contains both, BLAS and LAPACK, it needs to be set in both variables. An example to use a self-compiled reference BLAS and LAPACK could yield the following CMAKE call:

cmake ../ -DBLAS_LIBRARIES=/home/user/software/libblas.a \
          -DLAPACK_LIBRARIES=/home/user/software/liblapack.a

Cross Compiling for Windows

The build system supports cross compiling from Unix-like operating systems to Windows. Therefore, MingW64 (https://www.mingw-w64.org/) and Wine (https://www.winehq.org/) need to be present on the system. In case of Ubuntu 20.04 the following packages are required:

• mingw-w64, mingw-w64-i686-dev , mingw-w64-x86-64-dev
• gfortran-mingw-w64-i686, gfortran-mingw-w64-x86-64
• wine32, wine64
• wget

Furthermore, BLAS and LAPACK are required in the MingW installation. If this is not the case, the reference BLAS and LAPACK library can be installed via

 bash ./tools/install-lapack-mingw-i686.sh

for the Windows 32-bit environment, and using

bash ./tools/install-lapack-mingw-x86_64.sh

for the Windows 64-bit environment.

The Windows 32-bit library can then be compiled using

cmake -S . -B build.win32 \
      -DCMAKE_TOOLCHAIN_FILE=$(pwd)/cmake/mingw-w32-i686.cmake \
      -DBUILD_SHARED_LIBS=ON \
      -DCMAKE_INSTALL_PREFIX=$(pwd)/install-win32
make -C build.win32 all
(cd build.win32; ctest -V )
make -C build.win32 install

In case of the 64-bit Windows library, the build process looks like

cmake -S . -B build.win64 \
      -DCMAKE_TOOLCHAIN_FILE=$(pwd)/cmake/mingw-w64-x86_64.cmake \
      -DBUILD_SHARED_LIBS=ON \
      -DCMAKE_INSTALL_PREFIX=$(pwd)/install-win32
make -C build.win64 all
(cd build.win64; ctest -V )
make -C build.win64 install