May i know how you estimate the ZCA matrix? about semi-supervised-paper-implementation HOT 1 OPEN

I just rent an AWS instance and calculated the ZCA matrix of CIFAR10:
the result is different from yours:

my one(calculated based on the whole dataset, i.e. 50K images):
[[ 3.16225757e+00 -1.93212111e-05 -1.86190303e-05 ... -5.32311332e-06
-5.54466758e-06 -5.91178032e-06]
[-1.93212111e-05 3.16225810e+00 -1.90527165e-05 ... -5.17075653e-06
-5.37499166e-06 -5.64742587e-06]
[-1.86190303e-05 -1.90527165e-05 3.16225821e+00 ... -5.08378483e-06
-5.26505783e-06 -5.50406835e-06]
...
[-5.32311332e-06 -5.17075653e-06 -5.08378483e-06 ... 3.16226195e+00
-1.54090321e-05 -1.49700770e-05]
[-5.54466758e-06 -5.37499166e-06 -5.26505783e-06 ... -1.54090321e-05
3.16226180e+00 -1.56390237e-05]
[-5.91178032e-06 -5.64742587e-06 -5.50406835e-06 ... -1.49700770e-05
-1.56390237e-05 3.16226137e+00]]
size = (3072, 3072)

yours:
[[ 4.6536251e+01 -1.6922934e+01 -4.2759528e+00 ... 3.2285467e-01
-1.3231681e-01 -1.8512923e-01]
[-1.6922934e+01 6.5734108e+01 -2.5042648e+01 ... -6.3035327e-01
2.3367840e-01 1.9456828e-01]
[-4.2759528e+00 -2.5042648e+01 7.5144257e+01 ... 2.4870060e-01
1.9999361e-02 -2.3955733e-02]
...
[ 3.2285476e-01 -6.3035333e-01 2.4870069e-01 ... 7.9308556e+01
-3.2609344e+01 1.0282707e+00]
[-1.3231690e-01 2.3367813e-01 1.9999307e-02 ... -3.2609344e+01
7.7910210e+01 -2.8092228e+01]
[-1.8512926e-01 1.9456822e-01 -2.3955926e-02 ... 1.0282707e+00
-2.8092228e+01 5.6274792e+01]]
size = (3072, 3072)

based on the fomula, the ZCA matrix should be a diagnal matrix, and i think your matrix is not correct.

from semi-supervised-paper-implementation.