Chapter 2. Project Overview

Table of Contents

1. What is Sake?
2. What is Polynomial Regression?
3. Where is it?
4. License
5. Bugs, features requests and support?

1. What is Sake?

Sake is a PHP implementation of Polynomial Least Squares Regression. The algorithm takes data points as input and returns the resulting polynomial.

Graphs can be made using any plotting package. Sake provides the polynomial and will compute as many points as desired.

2. What is Polynomial Regression?

Polynomial regression is a model in the form of a polynomial function. The model is typically used to understand trends in a collection data points. It is often used in the analysis of behaviors in graphs. A simple linear example is shown bellow where the ci are coefficients, x is the input and y the output.

Equation 2.1. First Degree Polynomial

y = c1x + c0

Equation 2.2. Forth Degree Polynomial

y = c4x4 + c3x3 + c2x2 + c1x + c0

The coefficients are determined based on the input data set. The general equasion for the coefficients is shown below.

Equation 2.3. Least Squares

MC = Y

Table 2.1. Matrix M
n
Ʃ nx
-
Ʃ nxk
Ʃ nx
Ʃ nx2
-
Ʃ nxk+1
-
-
-
-
Ʃ nxk
Ʃ nxk+1
-
Ʃ nx2k
Table 2.2. Matrix C
c1
c2
-
ck+1
Table 2.3. Matrix Y
Ʃ ny
Ʃ nyt
-
Ʃ nytk

3. Where is it?

4. License

The MIT License

Copyright (c) 2008 Thomas Davis (sunsetbrew)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

5. Bugs, features requests and support?

Please report bugs, request features or support using the tracker at http://sourceforge.net/tracker/?group_id=243341. Using this interface will help others who may see the issue and help the project team prioritize and remember it.

As it says in the license, this software is "AS IS". While the project team wants to provide the best software, it does not constitute a waver in the license.