foundations-of-applied-mathematics / labs Goto Github PK

On page 8 of Python Essentials you are using the words "named arguments" without ever defining them.

It has come to my attention that the Exceptions and File IO lab has a section on string manipulation. It mentions format strings, but never mentions f strings. These are a more readable, more concise, and less prone to error than other ways of formatting, and they are also faster.

Example: In the third-to-last code block of the lab, you have the following code:
print("Is today {} {}, {}?".format(day, month, year))
Which could be simplified to the following using an f-string:
print(f"Is today {day} {month}, {year}?")

In addition, the statement " The comma after the print command suppresses the automatic newline character, keeping the output of each individual print statement on the same line" is no longer correct, and does not reflect the code as it is in the lab currently.

The statement " The comma after the print command suppresses the automatic newline character, keeping the output of each individual print statement on the same line" is no longer correct, and does not reflect the code as it is in the lab currently.

The ContentFilter class (problems 3 and 4), the doc string for the class is in the wrong place. It is written before the class definition.

This paragraph is incorrect.
https://github.com/Foundations-of-Applied-Mathematics/Labs/blob/master/PythonEssentials/StandardLibrary/StandardLibrary.tex#L151

Assigning a new name to an immutable object does not create a copy. Both names simply point to the same object in memory. IIRC, assignments in Python never create copies.

a = (1, 2, 3)  # immutable tuple
b = a    # b now references the same object as a
id(a) == id(a)    # True

Clarify in the problem where you add "hunter" to the last element of the string that they know it should read "bearhunter" not "bear hunter"

There is a typo in the Additional Material section regarding complex QR decomposition. As I was working to apply the changes, I think I found that the defined sign(x) function might be incorrect. I believe it should be sign = lambda x: x/np.abs(x) if x!=0 else 1 instead of sign = lambda x: 1 if np.real(x) >= 0 else -1.

Suggestion for @jhumpherys @tylerjarvis. I wanted to make a suggestion for the labs that would really give them more legs and accessibility. The Jupyter people have now come up with a format (Jupyter Book) that really marries the PDF concept with the html concept with the executable code concept in a way that can be version controlled. Here is the workflow.

1. Write content as markdown file (.md) along with some Jupyter configuration files and version control those in a GitHub repository.
2. Jupyter book sofware allows you to compile an html version of the book locally (for testing)
3. Set up GitHub Action on book source repository to push changes to a GitHub Pages site of the book upon commits to master.
4. The html site for the Jupyter Book labs would be very accessible, LaTeX- and BibTex-like links and math rendering, and with a click of a button, the page will open as a local Jupyter notebook or Jupyter Lab hosted notebook or a CoLab hosted notebook with executable code and with a specified code environment.

I think this is the sweet spot. We've moved all the documentation for a number of our open source projects over to Jupyter Books. The two following examples are still under development, but they are far enough along to show a lot of the functionality of the medium.

• The Tax-Calculator project's documentation is shown in the associated GitHub page in the upper-right corner. All the source code for that documentation is version controlled in the Tax-Calculator/docs/ folder. Whenever a pull-request is merged that has commits to the files in that folder, a GitHub Action deploys the updated version of the documentation to the GitHub page.
• Another example is the OG-USA model. The Jupyter Book documentation is at the GitHub page associated with the repo, and the source for the documentation is in the OG-USA/docs/ folder.

The transforms problem (#1) should say "return a transformation of the data" not "return the transformed data" because at least one student actually made his code transform the original data array, so that the data input for the next method was corrupted by the previous method. It's a subtle change in wording, but an important point for the students to learn.

In the test_driver.py file for breadth first search, two of the test graphs are directed, where students can only make undirected graphs on problem 2.
(see pictures file for more details)

There appears to be a typo in exercise 7 of Lab 08. In particular, there is a snippet of code which reads:

def matrix_power(A, n):
    """Compute A^n, the n-th power of the matrix A."""
    product = A.copy()
    temporary_array = np.empty_like(A[0])
    m = A.shape[0]
    for power in range(1, power):
        #...

I think that the for loop should be changed to:

     for power in range(1, n):

This can also be found on line 757 in the profiling.tex file

On the first page of the Breadth First Search Lab, the D row of this adjacency dictionary should be D : {A, B, C}.

It has come to my attention that the Exceptions and File IO lab has a section on string manipulation. It mentions format strings, but never mentions f strings. These are a more readable, more concise, and less prone to error than other ways of formatting, and they are also faster.

Example: In the third-to-last code block of the lab, you have the following code:
print("Is today {} {}, {}?".format(day, month, year))
Which could be simplified to the following using an f-string:
print(f"Is today {day} {month}, {year}?")

ADD F STRINGS WHERE NEEDED!!!

For the string magic method of ComplexNumber there's a "# Or, more likely," after the return statement with a way that students would probably code it. For the case where the complex part is negative it returns sign + str(self.imag) but a negative number cast as a string already has a negative sign. So this would print two negative signs.

I had two students who returned valid shortest path lists that did not match what the auto grader was expecting. Below you will find their code and feedback.

----------Student 1----------
CODE:
if source not in self.d.keys():
raise KeyError("source node not in graph")

    # initialize list
    V = [] 
    # initialize deque
    Q = deque(source)
    # initialize set
    M = set(source)


    #traverse through graph step

    while set(V) != set(self.d.keys()): # until traversed graph
        diff = self.d[source].difference(M)

        M = M.union(self.d[source]) # update
        for x in diff:

            Q.append(x)

        source = Q.popleft()

        V.append(source) #append visited nodes
    return V

FEEDBACK:
Problem 2 (10 points):
Graph.traverse('A') failed
Graph: {'A': {'C', 'B'}, 'B': {'D', 'E', 'A'}, 'C': {'F', 'G', 'A'}, 'D': {'H', 'I', 'B'}, 'E': {'K', 'J', 'B'}, 'F': {'M', 'L', 'C'}, 'G': {'N', 'O', 'C'}, 'H': {'D'}, 'I': {'D'}, 'J': {'E'}, 'K': {'E'}, 'L': {'F'}, 'M': {'F'}, 'N': {'G'}, 'O': {'G'}}
Correct response: "['A', 'C', 'B', 'F', 'G', 'D', 'E', 'M', 'L', 'N', 'O', 'H', 'I', 'K', 'J']"
Student response: "['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'K', 'J', 'M', 'L', 'N', 'O']"
Score += 8

----------Student 2----------
CODE:
#raise NotImplementedError("Problem 2 Incomplete")
V = [] # .append
Q = deque() #.append #pop(0)
M = set() #use .add

    M.add(source)                    #append the fist one
    Q.append(source)

    while len(Q) != 0:
        current_node = Q.popleft()          #pop the first one and call it current node
        V.append(current_node)           #append it to V
        for x in self.d[current_node]-M:       #for loop so we add each individually, and subtract M so we dont re-add stuff
            M.add(x)                                            #self.d[current_node] is the neighbors
            Q.append(x)

    return V

FEEDBACK:
Problem 2 (10 points):
Graph.traverse('A') failed
Graph: {'A': {'C', 'B'}, 'B': {'D', 'E', 'A'}, 'C': {'F', 'G', 'A'}, 'D': {'H', 'I', 'B'}, 'E': {'K', 'J', 'B'}, 'F': {'M', 'L', 'C'}, 'G': {'N', 'O', 'C'}, 'H': {'D'}, 'I': {'D'}, 'J': {'E'}, 'K': {'E'}, 'L': {'F'}, 'M': {'F'}, 'N': {'G'}, 'O': {'G'}}
Correct response: "['A', 'C', 'B', 'F', 'G', 'D', 'E', 'M', 'L', 'N', 'O', 'H', 'I', 'K', 'J']"
Student response: "['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'K', 'J', 'M', 'L', 'N', 'O']"
Score += 8