Detailing the Problem

For those that are reading this and have followed my post in the past, you may call me out as being a hypocrite. But, if you don’t know what I am talking about then you may view any article in my Algorithms from scratch series:

I was reading through an article that used coded examples with Medium’s code cells. I got so frustrated! I ended up copying and pasting the code into my visual studio environment and even this was wasn’t enough to save the code — There were no indentations so I basically had to clean the code myself.

If it wasn’t urgent that I understood that topic, I’d of probably clicked off that article and searched for a new one. It was a gruesome experience to say the least.

def plot_svm():
    ## https://scikit-learn.org/stable/auto_examples/svm/plot_separating_hyperplane.html
    ## getting the decision function
    plt.figure(figsize=(10, 5))
    decision_function = svc.decision_function(X)
    support_vector_indices = np.where((2 * y - 1) * decision_function <= 1)[0]
    support_vectors = X.iloc[support_vector_indices]

    ## plot observations
    plt.scatter(X.iloc[:, 0], X.iloc[:, 1], c=y, cmap=plt.cm.Paired)

    ## plot the decision function
    ax = plt.gca()
    xlim = ax.get_xlim()
    ylim = ax.get_ylim()

    ## creating the grid to evaluate the model
    xx, yy = np.meshgrid(np.linspace(xlim[0], xlim[1], 50),
                         np.linspace(ylim[0], ylim[1], 50))
    Z = svc.decision_function(np.c_[xx.ravel(), yy.ravel()])
    Z = Z.reshape(xx.shape)

    ## plot decision boundaries and margins
    plt.contour(xx, yy, Z, colors='k', levels=[-1, 0, 1], alpha=0.5,
                linestyles=['--', '-', '--'])

    ## plot support vectors
    plt.scatter(support_vectors.iloc[:, 0], support_vectors.iloc[:, 1], s=100,
                linewidth=1, facecolors='none', edgecolors='k')

    plt.title("Linear SVM (Hard Margin Classification)")
    plt.tight_layout()
    plt.show()

I don’t know if it is just me, but I find this extremely difficult to read. There is a way to format code in Medium’s code cells to make it appear more readable as I’ve done below…

def gradient_descent(X, y, params, alpha, n_iter): 
    """
    Gradient descent to minimize cost function
    __________________ 
    Input(s)
    X: Training data
    y: Labels
    params: Dictionary contatining random coefficients
    alpha: Model learning rate
    __________________
    Output(s)
    params: Dictionary containing optimized coefficients
    """
    W = params["W"] 
    b = params["b"]
    m = X.shape[0] ## number of training instances 

    for _ in range(n_iter): 
        ## prediction with random weights
        y_pred = np.dot(X, W) + b
        ## taking the partial derivative of coefficients
        dW = (2/m) * np.dot(X.T, (y_pred - y)) 
        db = (2/m) * np.sum(y_pred -  y)
        ## updates to coefficients
        W -= alpha * dW
        b -= alpha * db 

    params["W"] = W
    params["b"] = b
    return params

If you noticed, I’ve manually highlighted the Python built-ins in bold font and I’ve indented everything so it is pretty readable — I must have had the time that day because if you are writing a full technical blog, as I had done for this one, to do this to each bit of code you write is very, very, very long.

Detailing the Solution

A better strategy is to use Github Gist — For the veterans on here, you’d know this is far from some revolutionary discovery. I am going to use the first code cell (with difficult to read code) and create a Github Gist.

I am not a Math genius, but I am sure we can all agree that that is 3000 times much clearer than the Medium code cell we saw earlier. And to be honest, it makes sense, why…

#coding #programming #opinion #advice #technical-writing