Dear Dakshesh, thanks for your mail. Regarding your problem you could first try to switch on logging while running the simulation. Its explained here: https://tkwant.kwant-project.org/doc/dev/tutorial/logging.html Maybe you get some more specific error message from that. I would also suggest to not prebind parameters via "kwant.operator.Density(..).bind(params)". There was some issue with this kwant operator binding and tkwant should even complain when evaluating such an operator, if I remember correctly. Finally, if the problem persists, you could also send a mininal example which still reproduces the error to the list, in order to have a closer look. Best, Thomas ________________________________________ From: dakshesh.kololgi17@imperial.ac.uk [dakshesh.kololgi17@imperial.ac.uk] Sent: Sunday, March 28, 2021 3:09 AM To: kwant-discuss@python.org Subject: [Kwant] Memory error while using tkwant Dear users, I am a Physics Masters student and am using tkwant to simulate braiding (adiabatic exchanging) of Majorana fermions in a 2D system. Currently, even for the smallest systems, although these do work using Jupyter, I get a memory error when using my university's HPC supercomputer and MPI ranks. Also, when running simulations on Jupyter notebook (supercomputer client) any large-ish system never actually completes. More specifically, my issue seems to lie with 'wave_function.evolve' and 'wave_function.evaluate' for the time for loop. density_operator = kwant.operator.Density(syst, np.eye(8)).bind(params=params) wave_function = manybody.WaveFunction(psi_init, tasks) for time in times: wave_function.evolve(time) density = wave_function.evaluate(density_operator) densities.append(density) plt.plot(sites, density - density0, label='time={}'.format(time)) In my system, I have 4 time-dependent gates and they are supposed to turn on and off according to what time the system is in. I have used 'if' statements to specify when the gates should be on or off. If anyone can help it would be of great help. Thank you.