[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
## Re: Principle component analysis

**From**: |
E. Joshua Rigler |

**Subject**: |
Re: Principle component analysis |

**Date**: |
Thu, 16 Apr 2009 09:24:16 -0600 |

On Thu, Apr 16, 2009 at 8:54 AM, Oguz Yarimtepe <address@hidden> wrote:
>* Hi,*
>
>* I am trying to use PCA at my project. I need to get some graphics like*
>* the one here[1]*
>
>* I am not sure how will i use octave to create such graphics after*
>* applying princomp funtion to my dataset. Can someone help me on this?*
>
>* [1] http://tinypic.com/view.php?pic=9giped&s=5*
>
My guess is that the graphic you linked to is a plot of the first
column of the second output argument to princomp.m (i.e., the
"transformed data"). Either call princomp.m with a second output
argument, or multiply the demeaned input matrix by the principal
component matrix. (e.g.,
>*> pc = princomp(obs_matrix);*
>*> xform_matrix = center(obs_matrix)*pc;*
This is exactly what princomp.m does to get the transformed data.
-EJR