Becoming a Web Developer

Now that Grad School is over I’m moving on to the next exciting chapter of my career - I’m joining a great company called Shopify in the fall and I am going to be working as a Web Developer! I’m quite excited, in fact so excited I took a course from Udacity to get up to speed on some Web Dev basics.

CS 253 Web Development - Building a Blog with Steve Huffman (for those who don’t know this is the guy who started Reddit so he might know a thing or two about building websites) was a really great course and I would definitely recommend it to anyone who wants to learn a thing or two about the web. I also really liked Steve’s teaching style - while he did a great job explaining things simply he also wasn’t afraid to show how he really works i.e. in the terminal and using Linux/Unix commands etc. The course could have easily hidden all of this away but I think it was important to show - using windows and gui’s just isn’t how people work in this industry so why should the course be taught like so? Good job Steve for keeping it real!

Taking the class was really worthwhile as it helped tie together a bunch of knowledge I had accumulated randomly over the years and it helped make some sense of some of the Django hacking I did once upon a time(I say hacking because I got stuff to work but didn’t totally understand everything).

Here is my hard-earned certificate! I completed the course with High Distinction meaning I did all the homework, the final and the bonus question!

I also pushed all my code to my GitHub account:

https://github.com/pickle27/cs253_blog

https://github.com/pickle27/cs253_wiki

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One Example Three Languages

I wanted to post this example of my Google Summer of Code work because I think its neat. One of the cool things about Shogun is our great SWIG wrapper and our static interface which lets us use Shogun natively in a bunch of different languages. So here is an example program of doing Blind Source Separation using the Jade algorithm from Python, Octave and R:

"""
Blind Source Separation using the Jade Algorithm with Shogun
Based on the example from scikit-learn
http://scikit-learn.org/

Kevin Hughes 2013
"""

import numpy as np
import pylab as pl

from shogun.Features  import RealFeatures
from shogun.Converter import Jade

# Generate sample data
np.random.seed(0)
n_samples = 2000
time = np.linspace(0, 10, n_samples)

# Source Signals
s1 = np.sin(2 * time)  # sin wave
s2 = np.sign(np.sin(3 * time))  # square wave
S = np.c_[s1, s2]
S += 0.2 * np.random.normal(size=S.shape)  # add noise

# Standardize data
S /= S.std(axis=0)  
S = S.T

# Mixing Matrix
A = np.array([[1, 0.5], [0.5, 1]])

# Mix Signals
X = np.dot(A,S)
mixed_signals = RealFeatures(X)

# Separating
jade = Jade()
signals = jade.apply(mixed_signals)
S_ = signals.get_feature_matrix()
A_ = jade.get_mixing_matrix();

# Plot results
pl.figure()
pl.subplot(3, 1, 1)
pl.plot(S.T)
pl.title('True Sources')
pl.subplot(3, 1, 2)
pl.plot(X.T)
pl.title('Mixed Sources')
pl.subplot(3, 1, 3)
pl.plot(S_.T)
pl.title('Estimated Sources')
pl.subplots_adjust(0.09, 0.04, 0.94, 0.94, 0.26, 0.36)
pl.show()
% Blind Source Separation using the Jade Algorithm with Shogun
%
% Based on the example from scikit-learn
% http://scikit-learn.org/
%
% Kevin Hughes 2013

% Generate sample data
n_samples = 2000;
time = linspace(0,10,n_samples);

% Source Signals
S = zeros(2, length(time));
S(1,:) = sin(2*time);
S(2,:) = sign(sin(3*time));
S += 0.2*rand(size(S));

% Standardize data
S = S ./ std(S,0,2);

% Mixing Matrix
A = [1 0.5; 0.5 1]

% Mix Signals
X = A*S;
mixed_signals = X;

% Separating
sg('set_converter', 'jade');
sg('set_features', 'TRAIN', mixed_signals);
S_ = sg('apply_converter');

% Plot
figure();
subplot(311);
plot(time, S(1,:), 'b');
hold on;
plot(time, S(2,:), 'g');
set(gca, 'xtick', [])
title("True Sources");

subplot(312);
plot(time, X(1,:), 'b');
hold on;
plot(time, X(2,:), 'g');
set(gca, 'xtick', [])
title("Mixed Sources");

subplot(313);
plot(time, S_(1,:), 'b');
hold on;
plot(time, S_(2,:), 'g');
title("Estimated Sources");
# Blind Source Separation using the Jade Algorithm with Shogun
#
# Based on the example from scikit-learn
# http://scikit-learn.org/
#
# Kevin Hughes 2013

library('sg')

# Generate sample data
n_samples <- 2000
time <- seq(0,10,length=n_samples)

# Source Signals
S <- matrix(0,2,n_samples)
S[1,] <- sin(2*time)
S[2,] <- sign(sin(3*time))
S <- S + 0.2*matrix(runif(2*n_samples),2,n_samples)

# Standardize data
S <- S * (1/apply(S,1,sd))

# Mixing Matrix
A <- rbind(c(1,0.5),c(0.5,1))

# Mix Signals
X <- A %*% S
mixed_signals <- matrix(X,2,n_samples)

# Separating
sg('set_converter', 'jade')
sg('set_features', 'TRAIN', mixed_signals)
S_ <- sg('apply_converter')

# Plot
par(mfcol=c(3,1));

plot(time, S[1,], type="l", col='blue', main="True Sources", ylab="", xlab="")
lines(time, S[2,], type="l", col='green')

plot(time, X[1,], type="l", col='blue', main="Mixed Sources", ylab="", xlab="")
lines(time, X[2,], type="l", col='green')

plot(time, S_[1,], type="l", col='blue', main="Estimated Sources", ylab="", xlab="")
lines(time, S_[2,], type="l", col='green')

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