BLOCK implements the density matrix renormalization group (DMRG) algorithm for quantum chemistry.

BLOCK requires BLAS, LAPACK and BOOST. MPI library is needed for distributed-memory parallel compilation. BLOCK is compiled using the makefile supplied in the distribution. The following customizations need to be made to the makefile placed in the main directory ./Block.

Choose compilers by specifying,

CXX = g++  

For MPI-based parallel execution on distributed-memory machines,

    USE_MPI = yes
    MPICXX = mpicxx  

MPI library must be compiled using the same compiler as for compiling BLOCK. Intel compiler such as icpc is also supported with approriate compiling flags chosen automatically.

To enable MKL library,

    USE_MKL = yes

And supply MKL and BOOST libraries by giving the locations,

MKLLIB = /opt/intel/composer_xe_2013_sp1.0.080/mkl/lib/intel64/ 
MKLFLAGS = /opt/intel/composer_xe_2013_sp1.0.080/mkl/include

BOOSTLIB = /lib64/boost_1_55_0/lib/
BOOSTINCLUDE = /lib64/boost_1_55_0/include/

When the makefile is configured, run in the directory ./Block

    $./make

The successful compilation generates the executable block.spin_adapted, static and shared DMRG libraries libqcdmrg.a and libqcdmrg.so.

BLOCK can be tested by executing the script in the directory ./Block/dmrg_tests,

    $cd dmrg_tests
    $./runtest

The tests require Python to be installed on the system.

The standalone serial code can be executed running

    $block.spin_adapted input.dat > output.dat

input.dat is the input file and the output of the program is piped into the output file output.dat.

The MPI parallel mode can be called running

    $mpirun -np 4 block.spin_adapted input.dat > output.dat

Block is distributed under the GNU GPL license which is reproduced in the file LICENSE. In addition, Block contains a full copy of the Newmat C++ matrix library by Robert Davies.

We would appreciate if you cite the following papers in publications resulting from the use of Block:

• G. K.-L. Chan and M. Head-Gordon, J. Chem. Phys. 116, 4462 (2002),
• G. K.-L. Chan, J. Chem. Phys. 120, 3172 (2004),
• D. Ghosh, J. Hachmann, T. Yanai, and G. K.-L. Chan, J. Chem. Phys., 128, 144117 (2008),
• S. Sharma and G. K-.L. Chan, J. Chem. Phys. 136, 124121 (2012).

In addition, a useful list of DMRG references relevant to quantum chemistry can be found in the article above by Sharma and Chan.

The online documentation is available at https://sanshar.github.io/Block.