Hi,
Good idea, I did not think that. After printing out I see no zeros ~
Here is the output of x_std:
tensor([[  92.6681],
        [ 404.6292],
        [ 404.8976],
        [ 250.7227],
        [ 250.4256],
        [ 404.3423],
        [ 405.0550],
        [ 251.0206],
        [  92.5387],
        [  93.0143],
        [ 250.8486],
        [ 250.7405],
        [ 251.2732],
        [ 251.1312],
        [ 405.1576],
        [ 251.5628],
        [ 405.3494],
        [ 251.1480],
        [ 251.1116],
        [ 250.7486],
        [  92.4530],
        [ 404.8680],
        [ 405.2231],
        [ 404.7466],
        [ 251.1800],
        [ 251.3008],
        [ 404.9897],
        [  92.7674],
        [ 251.1480],
        [ 250.7218],
        [ 250.3925],
        [ 251.2240],
        [ 250.2169],
        [ 404.4504],
        [ 250.0995],
        [ 251.2035],
        [  92.9458],
        [ 249.7354],
        [ 404.9981],
        [ 404.6703],
        [ 251.3260],
        [ 405.0110],
        [ 250.1668],
        [ 404.6394],
        [ 250.3278],
        [ 251.0508],
        [ 251.0729],
        [ 250.6330],
        [ 405.1168],
        [ 250.6799],
        [  92.4707],
        [ 251.1223],
        [ 250.9282],
        [  92.1929],
        [ 251.3193],
        [  92.0439],
        [ 251.4816],
        [ 250.2316],
        [ 251.3165],
        [ 405.0492],
        [ 250.7802],
        [ 250.8962],
        [ 404.7462],
        [ 404.8201],
        [ 251.0861],
        [ 251.0475],
        [ 250.3490],
        [ 404.3512],
        [ 251.4652],
        [ 250.8202],
        [ 404.1475],
        [ 250.6063],
        [ 405.0731],
        [ 250.9353],
        [ 250.2173],
        [ 250.8657],
        [ 251.2978],
        [ 249.7068],
        [ 250.8334],
        [ 250.7502],
        [ 249.7354],
        [ 250.4344],
        [ 251.0381],
        [ 250.4152],
        [ 250.4865],
        [ 404.9912],
        [ 250.6725],
        [ 250.4263],
        [ 251.4652],
        [  92.8861],
        [ 250.4647],
        [ 250.7429],
        [ 250.6835],
        [ 250.9700],
        [ 404.8431],
        [ 250.6500],
        [ 250.9970],
        [ 250.8521],
        [ 405.1579],
        [ 404.6438],
        [ 250.6725],
        [ 250.1192],
        [ 250.4342],
        [ 404.7541],
        [ 404.9801],
        [ 404.9246],
        [ 251.1625],
        [  93.1926],
        [ 404.9897],
        [ 404.6542],
        [ 405.0998],
        [ 250.4555],
        [ 250.5661],
        [ 250.4902],
        [ 251.4263],
        [ 250.8609],
        [ 251.2598],
        [ 404.7595],
        [ 405.3346],
        [ 249.7911],
        [ 250.8093],
        [ 250.1427],
        [  92.8163],
        [ 250.6440],
        [ 250.3875],
        [ 250.8757],
        [ 251.1032],
        [ 404.8384]])
tensor([[nan., nan., nan.,  ..., nan., nan., nan.],
        [nan., nan., nan.,  ..., nan., nan., nan.],
        [nan., nan., nan.,  ..., nan., nan., nan.],
        ...,
        [nan., nan., nan.,  ..., nan., nan., nan.],
        [nan., nan., nan.,  ..., nan., nan., nan.],
        [nan., nan., nan.,  ..., nan., nan., nan.]])