Quick Start

Licensing

The full software license for DMRG++ version 3 can be found in file LICENSE in the root directory of the code. DMRG++ is a free and open source implementation of the DMRG algorithm. You are welcomed to use it and publish data obtained with DMRG++. If you do, please cite this work (see next subsection).

DISCLAIMER

 THE SOFTWARE IS SUPPLIED BY THE COPYRIGHT HOLDERS AND
 CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
 WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 COPYRIGHT OWNER, CONTRIBUTORS, UNITED STATES GOVERNMENT,
 OR THE UNITED STATES DEPARTMENT OF ENERGY BE LIABLE FOR
 ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
 OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
 DAMAGE.

 NEITHER THE UNITED STATES GOVERNMENT, NOR THE UNITED
 STATES DEPARTMENT OF ENERGY, NOR THE COPYRIGHT OWNER, NOR
 ANY OF THEIR EMPLOYEES, REPRESENTS THAT THE USE OF ANY
 INFORMATION, DATA, APPARATUS, PRODUCT, OR PROCESS
 DISCLOSED WOULD NOT INFRINGE PRIVATELY OWNED RIGHTS.

How To Cite This Work

\@article{re:alvarez0209,
author="G. Alvarez",
title="The Density Matrix Renormalization Group for
Strongly Correlated Electron Systems: A Generic Implementation",
journal="Computer Physics Communications",
volume="180",
pages="1572-1578",
year="2009"}

\@article{re:alvarez0310,
author="G. Alvarez",
title="Implementation of the SU(2) Hamiltonian
Symmetry for the DMRG Algorithm",
journal="Computer Physics Communications",
volume="183",
pages="2226-2232",
year="2012"}


\@article{re:alvarez0311,
author="G. Alvarez and  L. G. G. V. Dias da Silva and
E. Ponce and  E. Dagotto",
title="Time Evolution with the DMRG Algorithm:
A Generic Implementation
for Strongly Correlated Electronic Systems",
journal="Phys. Rev. E",
volume="84",
pages="056706",
year="2011"}

\@article{re:alvarez0713,
author="G. Alvarez",
title="Production of minimally entangled typical thermal states
with the Krylov-space approach",
journal="Phys. Rev. B",
volume="87",
pages="245130",
year="2013"}

And also:
\@article{re:alvarez08,
 re:webDmrgPlusPlus,
 Author = {G. Alvarez},
 Title = {DMRG++ Website},
 Publisher = {\\url{https://g1257.github.com/dmrgPlusPlus}} }

Code Integrity

Hash of the latest commit is also posted at

https://g1257.github.com/hashes.html

Latest commit should always be signed. Keys at https://g1257.github.com/keys.html

Building and Running DMRG++

Required Software

• GNU C++ or LLVM CLANG++ (C++17 is used)

• The BLAS and LAPACK library or equivalent

• [required] HDF5

• [required] boost-devel (boost-spirit) for Ainur Only headers files are used; boost runtime is not used.

• [required] cmake and dependencies

• [required] perl

• [required] GSL (GNU Scientific Library)

Downloading DMRG++

Create a directory somewhere and cd to it.

cd ../
git clone https://github.com/g1257/dmrgpp.git
cd dmrgpp/

Pull requests should be opened against the master branch.

Configure

Use the following command to configure DMRG++

cmake -B builddir [<options...>]

-B builddir creates a build directory named builddir (you can choose a different name if you prefer).

The [<options...>] part is where you specify other configuration options.

Common CMake Options

These options are generally useful for any CMake project:

• -DCMAKE_CXX_COMPILER=<compiler>: Specifies the full path to the C++ compiler.

  Example: -DCMAKE_CXX_COMPILER=clang++

• -DCMAKE_CXX_STANDARD=<standard>: Sets the C++ standard. The default is 17.

  Example: -DCMAKE_CXX_STANDARD=20

• -DCMAKE_BUILD_TYPE=<type>: Controls optimization level and debugging information. Common options are Debug, Release, RelWithDebInfo (default), and MinSizeRel.

• -G<generator>: Specifies the generator to create a native build system (e.g., "Unix Makefiles" for standard UNIX makefiles, "Ninja" for build.ninja or "Visual Studio 17 2022" for Visual Studio.

  Example: -GNinja

External dependencies (Third-Party Libraries)

To control where the project should find external dependencies installed on your system, you may pass -D<PackageName>_ROOT=/path/to/package/install to find a specific <PackageName> installed at /path/to/package/install.

External dependencies are: BLAS, Boost, GSL, HDF5, Kokkos, KokkosKernels, LAPACK and MPI.

Example: -DBoost_ROOT=/path/to/boost

Note on Catch2 and Kokkos: We use the Catch2 library as our unit test framework and Kokkos as required dependency. By default, our CMake is set up to use FetchContent to download these libraries if they aren't found on your system.

To force the use of a locally installed library and disable the automatic download fallback, use the following options (where Catch2 serves as an example):

-DCMAKE_REQUIRE_FIND_PACKAGE_Catch2=ON -DCatch2_ROOT=/path/to/catch2

By default, CMake tries to check externally dependencies that have been installed via FetchContent for updates. This can be avoided by configuring with

-DFETCHCONTENT_UPDATES_DISCONNECTED=ON

which might be especially useful when there is limited access to the internet.

Build and Test

After the configuration step succeeded, build using

cmake --build builddir

and test with

ctest --test-dir builddir --output-on-failure

Install

After building, install with

cmake --install builddir --prefix installdir

Running DMRG++

Assuming you are in dmrgpp/src, copy input2.ain to dmrgpp/src with

cp ../TestSuite/inputs/input2.ain .

and then you may run with

./dmrg -f ../TestSuite/inputs/input2.ain

You will now have two files a data2.hdf5 and an ASCII file runForinput2.cout. The name data2 is obtained from the corresponding label in the input file, in this case input2.ain. Normally the code writes stdout to runForinput2.cout for an input called input2.inp, and stderr to the terminal. If you would like to override the default inferred name runForinput2.cout you may use ./dmrg -f ../TestSuite/inputs/input2.ain -l myoutputfile If you would like stdout be written to the terminal say -l -

Profiling

DMRG++ uses Kokkos for its most compute intensive components. Thus, it supports profiling through Kokkos Tools. To use, e.g., the Space Time Stack tool set the KOKKOS_TOOLS_LIBS environment variable to the corresponding library path

export KOKKOS_TOOLS_LIBS=${YOUR_KOKKOS_TOOLS_INSTALL_DIR}/lib/libkp_space_time_stack.so

before running dmrg.