Running the model

Introduction to the Ising Model

Running the model

You have two options to choose from here: you can run either NetLogo or MATLAB simulation.

*Ising1.nlogo***

1. Set up the NetLogo Ising1 simulation with either only setup – 1 (shown above) or +1. Set the temperature at 0.0 and hit go.

What happens?

2. Change the temperature configuration in small steps (i.e., 0.2, 0.4, 0.6, etc.).

How does the simulation change as the temperature gets higher?

3. At what temperature does the simulation move away from ferromagnetic domains to paramagnetism?

4. Now switch the LetLogo Ising1 simulation to the other spin (+1 if you originally started with –1 or – if you began with +1). Repeat the previous steps.

Is the temperature at which paramagnetism prevails the same? If not, why not?

5. Finally, set the simulation up by clicking the middle setup button setup-random (as shown below). Move the temperature slider around until you just reach ferromagnetism with –1 of +1 dominant.

Is the temperature at which paramagnetism prevails the same? If not, why not?

ising.m

*ising.fig***

The picture on the left shows how the initial set up for the model looks like. Notice that the initial temperature is set to 2.269, which is the threshold value. The current temperature is the one being used in the simulation.

You could change the temperature using the Temperature slider. Notice that once you move the slider, New temperature is going to turn red.

You can also change how fast is the picture being updated by using the pop-up menu.

Reset Once you select the desired temperature, you can press the Reset button to change the Current temperature to match the New temperature. If the temperatures are different and resetting was successful, the New temperature will turn blue.

Run Press Run to start the simulation. The step number will indicate how far you are in the simulation.

Stop Press Stop if you don't want to run the simulation any further. Once you press Run again, the simulation will start from the beginning.

Exit Desirable way to end the simulation and close the window. Warning: If you press the x in the upper-right corner, you will get error messages.

Notes: In order to run the MATLAB simulation you will need to have both ising.m and ising.fig in the same directory.

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