自组织映射工作不完美,输出总是同一个类别

我想训练和测试科霍宁网络,这是一种自组织映射(Self Organizing Maps)。

我的问题是每次运行代码时,尽管使用了每次不同的随机权重矩阵,输出的值总是相同,不是0000就是1111!

我的数据集是下面链接中的3个小文本文件:请注意,我首先使用训练数据中的样本来检查我的代码是否正确,然后再使用测试数据。

数据集链接

#==============================================================#Import necessary Libraries#---------------------------import randomimport numpy as npimport pandas as pdimport matplotlib.pyplot as pltfrom Kohonen_Funcs import Train,Test#=============================================================# Reading Data#=============================================================patient = pd.read_fwf('patient.txt', header = None, delimiter="\t",keep_default_na=False)control = pd.read_fwf('control.txt', header = None, delimiter="\t",keep_default_na=False)#-------------------------------------------------------------test = np.loadtxt('test_dud_ten.txt', delimiter="\t",dtype = str,max_rows=4)#xt = test[:,0:650].astype(float)#-------------------------------------------------------------#=============================================================# convert Data into Arrays to deal with.#=============================================================xp = np.array(patient,dtype = float)xp = np.roll(xp, 10,axis = 1) # shift data on time axis by 10 to be alignedxc = np.array(control,dtype = float)xt = np.vstack((xp[0:2,:],xc[0:2,:]))#-------------------------------------------------------------#=========================# Initial Parameters:#=========================Alpha  = 0.6 # Learning RatioW = np.random.random((2,650))# Weights random Array 2 Rows 650 Columnsiter = 50 # Number of iterations #print(W,'\n')#========================# Training#========================W_Tr , t_used = Train(xp,xc,W,Alpha,iter)#print(W_Tr)#------------------------------------#========================# Testing#========================Result = Test(xt,W_Tr)print(Result)#------------------------------------

以下是我使用的函数:

#==============================================================#Import necessary Libraries#---------------------------import matplotlib.pyplot as pltimport numpy as npimport time#=============================================================def winner(dist):            # dist : 2 x 650 array    D = np.sum(dist,axis=1)  # sum all values on time axis    first_w  = D[0]    second_w = D[1]    if first_w < second_w: # if first w was closer (shorter distance)        return 0     else:        return 1 #------------------------------------#=============================================================def Train(x1,x2,Wr,a,iterations):    tic = time.time() # set a timer    subjects_range = int(2*x1.shape[0]) # 20    #--------------------------------------    x1 = np.vstack((x1,x1)) # 20x650    # Rearrange the array to make each group of 2 rows is similar    x1 = x1[np.ix_([0,10,1,11,2,12,3,13,4,14,5,15,6,16,7,17,8,18,9,19])]    #-------------------------------------------------------------------    x2 = np.vstack((x2,x2)) # 20x650    # Rearrange the array to make each group of 2 rows is similar    x2 = x2[np.ix_([0,10,1,11,2,12,3,13,4,14,5,15,6,16,7,17,8,18,9,19])]    #--------------------------------------    Dist1 = Dist2 = np.zeros_like(Wr)    for epoch in range(iterations):        for subject in range(0,subjects_range,2):            #-----------------( Dist : 2 x 20 )-----------------------            # Patient subjects            Dist1 = (Wr - x1[subject:subject+2,:])**2            win1 = winner(Dist1)            Wr[win1,:]+= a*(x1[subject,:]-Wr[win1,:]) # W1 = a * (X1-W1)            #---------------------------------------------------------            # Control subjects            Dist2 = (Wr - x2[subject:subject+2,:])**2            win2 = winner(Dist2)            Wr[win2,:]+= a*(x2[subject,:]-Wr[win2,:]) # W2 = a * (X2-W2)            #---------------------------------------------------------            a *= 0.5 # update Learning Ratio after each epoch    #===============================    toc = time.time() # reset the timer, and get time used    t_used = toc - tic    return Wr , t_used#------------------------------------#=============================================================def Test(test,W):    output = [] # list to store the output     subjects_range = int(2*test.shape[0]) # 8     xt = np.vstack((test,test)) # 8 x 650    # Rearrange the array to make each group of 2 rows is similar    xt = xt[np.ix_([0,4,1,5,2,6,3,7])]    dist = np.zeros_like(xt) # 8 x 650    for subject in range(0,subjects_range,2):        # for each subject calculate distance        dist[subject:subject+2,:] = (xt[subject:subject+2,:] - W)**2        # for each subject get to which class it belongs        win = winner(dist[subject:subject+2,:])        print(subject,'win = ',win)        output.append(win)    return output

回答:

整个问题出在权重上,由于它们是随机初始化的,无法保证结果正确。与其使用W = np.random.random((2,650)),我手动初始化了权重,得到了正确的结果。

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