Getting Started

This page walks through installing montecarlo and running a first Ising-model calculation.

Installation

montecarlo requires Python 3.8 or higher and depends on NumPy and NetworkX. Clone the repository and install it in development mode:

git clone https://github.com/max-miller1204/montecarlo.git
cd montecarlo
pip install -e .

To also install the test dependencies, use:

pip install -e ".[test]"

Quickstart

The example below builds a 6-site ring with antiferromagnetic coupling and computes exact thermodynamic averages at temperature T = 1:

import networkx as nx
import montecarlo

N = 6
G = nx.Graph()
G.add_nodes_from(range(N))
G.add_edges_from([(i, (i + 1) % N) for i in range(N)])
for e in G.edges:
    G.edges[e]['weight'] = 2.0

ham = montecarlo.IsingHamiltonian(G)
E, M, HC, MS = ham.compute_average_values(T=1.0)

print(f"E  = {E:.6f}")
print(f"M  = {M:.6f}")
print(f"HC = {HC:.6f}")
print(f"MS = {MS:.6f}")

For systems where exact enumeration of all \(2^N\) configurations is too expensive, use the Metropolis sampler:

mc = montecarlo.MonteCarlo(ham)
energies, magnetizations = mc.run(T=2.0, n_samples=10_000, n_burn=200)

import numpy as np
print(f"<E> ~ {np.mean(energies):.4f}")
print(f"<M> ~ {np.mean(magnetizations):.4f}")

See the User Guide for a more detailed walkthrough and the API Documentation for the full API reference.