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这是我的矩阵分解代码的一部分（一个非常奇怪的 nmf 版本）。我的问题是，虽然每次迭代时，我都会保存 W 和 H 矩阵的旧副本，但当我在 W 每次完成更新后比较 old_W 和 W 时，它们实际上是相同的！所以实际的错误输出总是 0 并且 while 循环在第一次迭代后停止。但是，“#print old - new”显示元素 W[r][i] 实际上每次都会更新。什么是我没有看到的？
def csmf(V, l, max_iter, err, alpha=0.01, beta=0.01, lamb=0.01):
W = np.random.rand(V.shape[0], l)
H = np.random.rand(l, V.shape[1])
n = V.shape[0]
N = V.shape[1]
NwOone = 60
NwOtwo = 60
NhOone = 50
NhOtwo = 50
for t in range(max_iter):
old_W = W # save old values
old_H = H
old = criterion(V,old_W,old_H,l,alpha,beta,lamb)
print "iteration ", t
##### update W
print "updating W"
setw = range(0,n)
subset_one = random.sample(setw,NwOone)
subset_two = calcGw(V, W, H, n, l, alpha, beta, NwOtwo)
chosen = np.intersect1d(subset_one,subset_two)
for r in chosen:
for i in range(len(W[0])):
update = wPosNeg(W[r],N,i,l,V,r,beta,H)
old = W[r][i]
W[r][i] = update
new = W[r][i]
#print old - new
##### update H
print "updating H"
seth = range(0,N)
subset_oneh = random.sample(seth,NhOone)
subset_twoh = calcGh(V, W, H, N, l, NhOtwo,lamb)
chosenh = np.intersect1d(subset_oneh,subset_twoh)
for s in chosenh: # column
for i in range(len(H)):
updateh = hPosNeg(H[i],n,i,l,V,s,lamb,W)
H[i][s] = updateh
##### check err
print "Checking criterion"
print criterion(V,W,H,l,alpha,beta,lamb)
print criterion(V,old_W,old_H,l,alpha,beta,lamb)
actual = abs(criterion(V,W,H,l,alpha,beta,lamb) -criterion(V,old_W,old_H,l,alpha,beta,lamb))
if actual |