This post is intended to assist folks who are trying to install and work with grunt on mac osx

Install Node.js and npm with Homebrew #

First, install Homebrew by typing in the following command ruby -e “$(curl -fsSL https://raw.github.com/Homebrew/homebrew/go/install)"

Then, type in brew update to ensure your Homebrew is up to date.

brew update

Run

brew doctor 

to make sure your system is all good.

Follow any other recommendations from brew doctor.

Range Normalization is a normalization technique that allows you to map a number to a specific range.

Lets say that we have a data set where the values are in a range of 1 to 10, however we wish to normalise it to a range between 0 and 5

Mathematically speaking the equation comes down to

translated to Python

class Normaliser:

   def \_\_init\_\_(self,dH,dL,nH,nL):
       self.dH = dH
       self.dL = dL
       self.nH = nH
       self.nL = nL

   def normalize(self,x):
       return ((x - self.dL) / (self.dH - self.dL))  * (self.nH - self.nL) + self.nL

   def denormalize(self,x):
       return ((self.dL - self.dH) * x - self.nH * self.dL + self.dH * self.nL) / (self.nL - self.nH)

if \_\_name\_\_ == "\_\_main\_\_":
   norm = Normaliser(10,1,5,0);

   for a in range(1,11):
       x = norm.normalize(a);
       y = norm.denormalize(x);
       print str(a) + " : " + str(x) + " : " + str(y)

The results

In computer science, a ternary search tree is a type of prefix tree where nodes are arranged as a binary search tree. Like other prefix trees, a ternary search tree can be used as an associative map structure with the ability for incremental string search. However, ternary search trees are more space efficient compared to standard prefix trees, at the cost of speed. Common applications for ternary search trees include spell-checking and auto-completion.

As with other trie data structures, each node in a ternary search tree represents a prefix of the stored strings. All strings in the middle subtree of a node start with that prefix.