feat: add main w terminal execution of lattice size and optional visu…

…alisation via --plot

main.py

@@ -0,0 +1,58 @@
+import numpy as np
+import argparse
+from src.py_ising_2d import Config, mc_metro_random, initial_lattice, calc_magnetisation, plot_results
+
+def run_simulation(n, plot):
+    config = Config(n=n)
+
+    for t_index, temp in enumerate(config.T):
+        M1 = 0
+        M2 = 0
+        spin_config = initial_lattice(config.n)
+        beta = 1.0 / temp
+
+        # Equilibrate the system
+        for _ in range(config.eq_steps):
+            mc_metro_random(spin_config, config.n, beta)
+
+        # Perform Monte Carlo steps
+        for _ in range(config.mc_steps):
+            mc_metro_random(spin_config, config.n, beta)
+            mag = calc_magnetisation(spin_config)
+
+            M1 += mag
+            M2 += mag * mag
+
+        # Store results
+        config.M[t_index] = config.norm_1 * M1
+        config.Chi[t_index] = (config.norm_1 * M2 - config.norm_2 * M1 * M1) * beta
+
+    # Output results for the current lattice size
+    print(f"Lattice size {n} completed.")
+    print("\nMagnetizations:")
+    print(np.array2string(config.M, formatter={'float_kind':lambda x: "%.4f" % x}))
+    print("\nSusceptibilities:")
+    print(np.array2string(config.Chi, formatter={'float_kind':lambda x: "%.4f" % x}))
+
+    # Plot the results if the plot flag is set
+    if plot:
+        plot_results(config.T, config.M, config.Chi, n)
+
+def main():
+    parser = argparse.ArgumentParser(description="Monte Carlo Simulation using the Metropolis algorithm.")
+    parser.add_argument(
+        "lattice_size",
+        type=int,
+        help="Size of the lattice (e.g., 4, 8, 16, 32)"
+    )
+    parser.add_argument(
+        "--plot",
+        action='store_true',
+        help="Plot the results after simulation"
+    )
+
+    args = parser.parse_args()
+    run_simulation(args.lattice_size, args.plot)
+
+if __name__ == "__main__":
+    main()