Calculate the counter-clock-wise angle degree between two vectors

	from __future__ import division
	from math import atan2
	# reference: http://stackoverflow.com/questions/23408572/angle-between-two-points-0-360-cw
	def calcVectAngle(vec1, vec2):
	""" calculate the counter-clock-wise angle between two vectors """
	angle = atan2(vec1[1], vec1[0]) - atan2(vec2[1], vec2[0])
	angle = angle * 360 / (2 * pi)
	if angle < 0:
	angle += 360
	print angle

view raw VectorAngle.py hosted with ❤ by GitHub

Execute python code using ./

Step1: add #!/usr/local/bin/python in the first line of the code

Step2: in the bash, type chmod +x myscript.py

Step3: type ./myscript.py to execute the python code

"[[0] * n] * m" is not equal to "[[0 for i in range(n)] for j in range(m)]"

	# When generate list of list, be careful of following methods, they produce different results
	>>> x = [[0] * 2] * 3
	>>> x
	[[0, 0], [0, 0], [0, 0]]
	>>> y = [[0 for i in range(2)] for j in range(3)]
	>>> y
	[[0, 0], [0, 0], [0, 0]]
	# although they look the same and are equal to each other
	>>> x == y
	True
	# but... the operation can generate different results
	>>> x[0][0] = 1
	>>> x
	[[1, 0], [1, 0], [1, 0]] # Surprise!! every list is changed
	>>> y[0][0] = 1
	>>> y
	[[1, 0], [0, 0], [0, 0]] # this is what we expected

view raw List.py hosted with ❤ by GitHub

Use Jazzy to generate Swift documentation.

Format:

• /// description
• - parameter param: description
• - returns: xxxxxxx

run Jazzy

$ jazzy --min-acl internal --swift-version 2.1

Embed images to latex

\graphicspath{ {pic/} } % The folder containing images.
\includegraphics[scale=0.5]{imageName} % Embed a image.

CS229 Machine Learning - 3 (Linear regression, Probabilistic interpretation, Logistic regression, Newton's method)

Outline:
- Linear regression
- Probabilistic interpretation
- Logistic regression
- Newton's method