from numpy import *

def loadDataSet(fileName):
    dataMat = []
    with open(fileName) as fr:
        for line in fr.readlines():
            curLine = line.strip().split('\t')
            fltLine = list(map(float, curLine))
            dataMat.append(fltLine)
    return dataMat

def distEclud(vecA, vecB):
    return sqrt(sum(power(vecA - vecB, 2)))

def randCent(dataSet, k):
    n = shape(dataSet)[1]
    centroids = mat(zeros((k,n)))
    for j in range(n):
        minJ = min(dataSet[:, j])
        rangeJ = float(max(dataSet[:, j]) - minJ)
        centroids[:, j] = minJ + rangeJ * random.rand(k,1)
    return centroids

def kMeans(dataSet, k, distMeas = distEclud, createCent = randCent):
    m = shape(dataSet)[0]
    clusterAssment = mat(zeros((m,2)))
    centroids = createCent(dataSet, k)
    clusterChanged = True
    while clusterChanged:
        clusterChanged = False
        for i in range(m):
            minDist = inf
            minIndex = -1
            for j in range(k):
                distJI = distMeas(centroids[j,:], dataSet[i,:])
                if distJI < minDist:
                    minDist = distJI
                    minIndex = j
            if clusterAssment[i,0] != minIndex:
                clusterChanged = True
            clusterAssment[i,:] = minIndex, minDist**2
        print(centroids)
        for cent in range(k):
            ptsInClust = dataSet[nonzero(clusterAssment[:, 0].A == cent)[0]]
            centroids[cent,:] = mean(ptsInClust, axis=0)
    return centroids, clusterAssment

def biKmeans(dataSet, k, distMeas = distEclud):
    m = shape(dataSet)[0]
    clusterAssment = mat(zeros((m,2)))
    centroid0 = mean(dataSet, axis = 0).tolist()[0]
    centList = [centroid0]
    for j in range(m):
        clusterAssment[j, 1] = distMeas(mat(centroid0), dataSet[j, :]) ** 2
    while (len(centList) < k):
        lowestSSE = inf
        for i in range(len(centList)):
            ptsInCurrCluster = dataSet[nonzero(clusterAssment[:,0].A == i)[0],:]
            centroidMat, splitClustAss = kMeans(ptsInCurrCluster, 2, distMeas)
            sseSplit = sum(splitClustAss[:,1])
            sseNotSplit = sum(clusterAssment[nonzero(clusterAssment[:,0].A!= i)[0],1])
            print('sseSplit, and notSplit:', sseSplit, sseNotSplit)
            if (sseSplit + sseNotSplit) < lowestSSE:
                bestCentToSplit = i
                bestNewCents = centroidMat
                bestClustAss = splitClustAss.copy()
                lowestSSE = sseSplit + sseNotSplit
        bestClustAss[nonzero(bestClustAss[:,0].A == 1)[0],0] = len(centList)
        bestClustAss[nonzero(bestClustAss[:,0].A == 0)[0],0] = bestCentToSplit
        print('the bestCentToSplit is:', bestCentToSplit)
        print('the len of bestClustAss is:', len(bestClustAss))
        centList[bestCentToSplit] = bestNewCents[0, :]
        centList.append(bestNewCents[1,:])
        clusterAssment[nonzero(clusterAssment[:,0].A == bestCentToSplit)[0],:] = bestClustAss
    return mat(centList), clusterAssment


