This is the used code for the simulations of the paper: 'Exchanging replicas with unequal cost, infinitely and permanently' by Sander Roet, Daniel T. Zhang and Titus S. van Erp, which can be found on arXiv (https://arxiv.org/abs/2205.12663). It is not user-friendly and highly optimized for our specific hardware and output requirements. **We would advice anyone to use the examples of the infretis github(https://github.com/infretis/infretis) instead.** The required dependencies are: - All requirements for PyRETIS (`conda install --only-deps pyretis`) - The development branch of PyRETIS (`pip install git+https://gitlab.com/pyretis/pyretis.git@develop`) And because the MSVS system is based on code in a jupyter notebook (https://jupyter.org/) it also requires: - jupyter (`conda install jupyter`) To run the two-channel system or the 1D double well potential with wire fencing: 1. Go to the directory of the system you want to run 2. Open the `run.py` file and update the variables `n_workers` and `walltime` to the wanted values 3. Run `python run.py` To run the MSVS system: 1. Go to the MSVS directory 2. Open the IPython notebook with `jupyter notebook MSVS.ipynb` 3. Change the values of `n_workers` and `walltime` to the wanted values 4. Rerun all cells

We acknowledge funding from the Research Council of Norway through FRINATEK Project No. 275506.