|
|
|
Matlab can be accessed on any computer with internet by going to
http://www.loyola.edu/moresoftware/
and clicking "Go to Login". Log into Citrix using your Loyola username and password. From there click "Academic Applications" and then "MatLab 7". A prompt will come up and click "Allow".
The first thing to do once Matlab is loaded is to change your Current Directory to your G: drive, which is simple to do. Just click the button with the ellipsis . . . on it and scroll up to the G: drive. Therefore, everything will be saved to your G drive. So, now you can start experimenting!
Matlab is like a glorified calculator. You can add (+), subtract (-), multiply (*), divide(/), and take powers (^). For example, at the prompt you can add 2 and 4 and cube the quantity by typing
>> (2+4)^3
and hitting the "Return" key. Matlab will spit out
ans =
216
You can also assign variables in Matlab. Suppose you want to know how much 2 chairs and a table would cost if you knew that a chair is $5 and a table is $10. In Matlab, you would type the following
>>chair = 5, table = 10
chair =
5
table =
10
>> 2*chair + 1*table
ans =
20
For this lab we are interested in plotting functions. To do this you need a list of x values and a list of y values. So, how do you create a list? The easiest way is to just list the numbers. Suppose you wanted the numbers 1,2,3,4,5. Then in Matlab you would just type
x = [1 2 3 4 5]
x =
1 2 3 4 5
Another option is to use the bracket notation [start:increment:end]. For example, if you want the values between 0 and 1, incremented by .25 for x, you would type
>>x = [0:.25:1]
x =
0 0.2500 0.5000 0.7500 1.0000
Yet another option is to use the command linspace. For example,
>>x = linspace(-50,50,200);
will create 200 equally spaced points between -50 and 50, and will store the values in the variable x.
Now, you can create y values that are based on these x-values. If you are using the commands * / ^, remember to put a . before the operations so that the command will be given component-wise. For example, if you wanted to square each element of x, you would use the command
>>y = x.^2;
Now that you have a list of x and y values you can plot the graph with the command
>>plot(x,y);
For different methods for plotting such as colors and marker style, type
>>help plot
and a list will be given showing the different options. For example, to have a plot of red circles, you would type
>>plot(x,y,'ro');
To add graphs to the figure use the command hold on, while the command hold off will release the graph. That is it! You should now have all the tools necessary to plot your first graph. You can see an example of code to draw a lollipop here. Experiment and make some pretty pictures!
|
|
