Comp-phys-alps-users

comp-phys-alps-users@lists.phys.ethz.ch

October 2020

3 participants
2 discussions

Questions about MC Simulation of XY Model
by Wei Wang 26 Oct '20

26 Oct '20

Hi, I am just new to ALPS, and I have a silly question about running MC simulations of XY model: Following the tutorials, I use python to run the simulations and change the model from “Ising” to “XY”, like: > import pyalps > > parms = [ > { > 'LATTICE': "square lattice", > 'T': 1, > 'J': 1, > 'THERMALIZATION': 10000, > 'SWEEPS': 400000, > 'UPDATE': "cluster", > 'MODEL': "XY", > 'L': 8 > } > ] > > input_file = pyalps.writeInputFiles('data/parmXY', parms) > pyalps.runApplication('spinmc', input_file, Tmin=5) > result_files = pyalps.getResultFiles(prefix='data/parmXY') > > data = pyalps.loadMeasurements(result_files) > how can I get some observables like <\cos\theta>, where \theta is the direction of the spin at each site? If such a quantity is not provided directly by ALPS, is there a possible method to get these quantities I want. I just get lost when I see the source code of ALPS. Thank you in advance! Best, Wei

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Question of MC Simulation for XY Model
by Wei Wang 13 Oct '20

13 Oct '20

Hi, I am just new to ALPS, and I have a question about running MC simulations of XY model: Following the tutorials, I use python to run the simulations and change the model from “Ising” to “XY”, like: > import pyalps > parms = [ > { > 'LATTICE': "square lattice", > 'T': 1, > 'J': 1, > 'THERMALIZATION': 10000, > 'SWEEPS': 400000, > 'UPDATE': "cluster", > 'MODEL': "XY", > 'L': 8 > } > ] > input_file = pyalps.writeInputFiles('data/parmXY', parms) > pyalps.runApplication('spinmc', input_file, Tmin=5) > result_files = pyalps.getResultFiles(prefix='data/parmXY') > data = pyalps.loadMeasurements(result_files) how can I get some quantities like $$<M_x^2>=<\cos^2\theta>$$, or the nematic $$<N_x>=<\cos 2\theta>$$, where $$\theta$$ is the direction of the spin at each site? Is it possible to get these quantities I want through ALPS? Really hope someone can give me a hint to do this. Thank you in advance! Best, Wei

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