#coding:utf-8

from numpy import *

def loadDataSet(filename,delim = '\t'):

    fr = open(filename)

    stringArr = [line.strip().split(delim) for line in fr.readlines()]

    datArr    = [map(float,line) for line in stringArr]

    return mat(datArr)

def pca(datamat,topNfeat = 999999):

    meanVals    = mean(datamat,axis = 0)

    meanRemoved = datamat -meanVals

    covMat      = cov(meanRemoved,rowvar = 0)

    eigVals,eigVect = linalg.eig(mat(covMat))

    eigValInd       = argsort(eigVals)

    eigValInd       = eigValInd[:-(topNfeat+1):-1]

    redEigVects     = eigvals(:,eigValInd)

    lowDDataMat     = meanRemoved*redEigVects

    reconMat        = (lowDDataMat*redEigVects.T)+meanVals

    return lowDDataMat,reconMat