Assignment 5 OOPs I did it again

MATLAB Assignment 5
, Section A
In this homework, we will go through a few advanced data structures in MATLAB, such as cell
arrays, classes, chars, as well as dataset-importing. You will be importing in the fisheriris dataset
and encapsulating it in classes. After obtaining all the data, you will be required to write some
methods for the class you just created. Also note that some operations will require you to do some
research, but not too much!
Please submit this homework as .m files with suppressed output (obviously, the plots should still be
displayed). Remember that all lectures and homeworks may be found at github.com/guybaryosef/ECE210-
materials. This homework is due by 4:00 PM on March 25th to guybymatlab@gmail.com. Remember to also bring a hardcopy in to class!
1. OOPs I did it again
a. Load in the fisheriris dataset with the command load fisheriris. You should obtain a 150 × 4
matrix called meas, as well as a 150 × 1 cell array called species in your workspace. This is a
very popular dataset, and you can quickly google fisherisis to see what the columns of meas
represent.
b. Create a class called Flower in its own .m file. In your Flower class, you should have the
following properties:
• petalWidth (double)
• petalLength(double)
• sepalWidth(double)
• sepalLength(double)
• species(char).
The ith species corresponds to the ith row of information in meas. Note that you do not need to
specify the data type of the properties when you are declaring a class - the following properties
are just here to impress on you what type of properties you would be expecting.
c. Create a constructor for your class. It should take in 4 doubles and a char array corresponding,
in order, to the five properties of your class.
d. Now, import the entries from meas and species into MATLAB and store them in a 150×1 cell
array of Flower instances. You can either use a for loop to import the entries, or use a more
elegant way to create all entries in one line (this would require some research on object formation
in MATLAB). Either way is OK. However, note that the names of the species are stored as cell
arrays; make sure to extract them from the cell as a char and remove trailing white spaces before
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storing them in the Flower instances. There is a single function that will do this, which you
should be able to find with a quick google search.
e. Create a method called getSLength for the Flower object, which will return the sepal length of
the object. Use this on the 25th Flower in your cell array, and check (using ==) that this is the
correct value by comparing it to the corresponding entry in meas.
f. Create another method called report for the Flower object, which will print out a statement on
the command window and report the details about the Flower object. This function does not
need to return anything. It should print out a statement of the following form if the flower is
5.1 cm in sepal length, 3.5 cm in sepal width, 1.4 cm in petal length, 0.2 cm in petalWidth, and
the species is setosa, for example:
“The length and width of its sepal are 5.1 cm and 3. 5cm respectively, while the length and
width of its petal are 1.4cm and 0.2cm respectively. It belongs to the setosa species.”
Bonus (These two questions below are together worth 1 extra point):
2. As computer programmers, when we see a number such as 1.9999999 as the output of some
function, we are quick to assume that the output is really 2 and that this is simply the effects of
quantization. However this is not always the case- there are some numbers, sometimes coined as
near integers, that closely, but not exactly, resemble integers.
Although this could often lead to an obscure and difficult distinction in computer programming, in
MATLAB we can use the symbolic toolbox to find the exact values of such numbers. Actually, if
you want to be technical about it, you will never find the exact value of these numbers, but rather
will get as close to the exact value as you wish.
Take as an example Ramanujan’s Constant, e
(π
√
163)
.
a First try to calculate its value using regular variables (i.e. a double).
b Next use the symbolic toolbox’s sym function to get a symbolic representation of this number.
Then use vpa to get a 30 and 100 digit representation of this number.
c Create a table comparing these 3 values.
3. Lets try a different, but equally interesting, experiment. Although it is believed that as the
decimal digits of π go into infinity each digit appears equally often, no such proof exists. Let us
see if we can garner some intuition on this:
Use vpa to get the first 10001 digits of π, convert the resulting number into a char, and then iterate
through it, keeping tally of the amount of times each digit appears. Finally, create a histogram of
the frequency of each digit.
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