TorsoMaxSAT

A MaxSAT solver based on Tree Decompositions of the Torso Graph.

Run Examples

You can run the solver (with some of the provided examples) as follows:

xz -cd examples/<file> | python main.py

In TorsoMaxSAT you have the option to chose one of multiple predefined solvers via:

xz -cd examples/<file> | python main.py -s <solver>

Where <solver> is one of gurobi, scip, rc2, hs, fm, ortools, or dp. Alternatively, <solver> can also be a command used to execute an external solver.

Using Subsolvers

If TorsoMaxSAT is used with option -s dp the instance is solved with a dynamic program on the formulas torso, whereby subinstances are solved with another solver (called subsolver). This subsolver can be specifed via --subsolver <solver> with the same options as for -s. For instance:

xz -dc examples/<file>  | python main.py -s dp --subsolver rc2 

Use an External Treewidth Solver

TorsoMaxSAT computes tree decompositions by default with NetworkX. However, it supports external treewidth solvers that are compatible with the PACE format:

xz -cd examples/<file> | python main.py -s db --twsolver <cmd>

Here, <cmd> is the command that should be executed to run the external treewidth solver.

Preprocessing

TorsoMaxSAT supports the MaxSAT preprocessor maxpre2. By providing a path to the executable, all implemented solvers will operate on a preprocessed formula:

xz -cd examples/<file> | python main.py --maxpre <path to maxpre executable>

Currently, we do not support configurations of maxpre but use a carefully chosen setting tailored toward a decomposition-guided approach. In particular, <path to maxpre executable> should indeed map to the executable and should not contain any flags or options.

Install the Conda Environment

After having downloaded the repository and moved to its root, you can install your conda environment as follows:

conda config --add channels conda-forge
conda config --set channel_priority strict
conda env create -f environment.yml

Additional Packages

The following packages need to be installed addionaly via pip:

pip install gurobipy
pip install 'python-sat[aiger,approxmc,pblib]'
pip install ortools

Updating the Conda Environment

conda env update --file environment.yml --prune

Testing the Solver

Run the following command to see if the installation works as intended:

python -m unittest -v