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Posted to commits@mxnet.apache.org by GitBox <gi...@apache.org> on 2018/06/08 16:23:02 UTC

[GitHub] thomelane opened a new issue #11203: ConvTranspose2d giving incorrect output

thomelane opened a new issue #11203: ConvTranspose2d giving incorrect output
URL: https://github.com/apache/incubator-mxnet/issues/11203
 
 
   When applying ConvTranspose2d with stride and dilation, the output is incorrect.
   
   Working through a simple example:
   
   * Input Shape: 1x3x3
   * Kernel size: 3x3
   * Padding: Same (i.e.2x2 in this case)
   * Stride: 2x2
   * Dilation: 2x2
   
   # Manual Calculation
   
   ![incorrect_trans2](https://user-images.githubusercontent.com/4902813/41142087-497e3348-6aa9-11e8-9a60-a465a5d07e8b.png)
   
   # MXNet Output
   
   We get a different output from MXNet, which I believe is incorrect. Output is offset at top and left sides, and then clusters on bottom and right sides.
   
   ```
   ...
   conv = mx.gluon.nn.Conv2DTranspose(in_channels=1, channels=1,
                                      kernel_size=(3,3), padding=(2,2),
                                      strides=(2,2), dilation=(2,2))
   ....
   ```
   ```
   [[[[ 0.  0.  0.  0.  0.]
      [ 0.  1.  0.  2.  3.]
      [ 0.  0.  0.  0.  0.]
      [ 0.  4.  0.  5.  6.]
      [ 0.  7.  0.  8.  9.]]]]
   <NDArray 1x1x5x5 @cpu(0)>
   ```
   
   # PyTorch
   
   Also, PyTorch returns an output that matches the manual calculations above. Code for this can be found below too.
   
   ```
   ...
   conv = torch.nn.ConvTranspose2d(in_channels=1, out_channels=1,
                                   kernel_size=(3,3), padding=(2,2),
                                   stride=(2,2), dilation=(2,2))
   ...
   ```
   ```
   tensor([[[[ 1.,  0.,  2.,  0.,  3.],
             [ 0.,  0.,  0.,  0.,  0.],
             [ 4.,  0.,  5.,  0.,  6.],
             [ 0.,  0.,  0.,  0.,  0.],
             [ 7.,  0.,  8.,  0.,  9.]]]])
   ```
   
   
   ## Environment info (Required)
   
   ```
   (mxnet_p36) ubuntu@ip-172-31-68-231:~$ python diagnose.py
   ----------Python Info----------
   Version      : 3.6.4
   Compiler     : GCC 7.2.0
   Build        : ('default', 'Jan 16 2018 18:10:19')
   Arch         : ('64bit', '')
   ------------Pip Info-----------
   Version      : 10.0.1
   Directory    : /home/ubuntu/anaconda3/envs/mxnet_p36/lib/python3.6/site-packages/pip
   ----------MXNet Info-----------
   Version      : 1.2.0
   Directory    : /home/ubuntu/anaconda3/envs/mxnet_p36/lib/python3.6/site-packages/mxnet
   Commit Hash   : 297c64fd2ee404612aa3ecc880b940fb2538039c
   ----------System Info----------
   Platform     : Linux-4.4.0-1057-aws-x86_64-with-debian-stretch-sid
   system       : Linux
   node         : ip-172-31-68-231
   release      : 4.4.0-1057-aws
   version      : #66-Ubuntu SMP Thu May 3 12:49:47 UTC 2018
   ----------Hardware Info----------
   machine      : x86_64
   processor    : x86_64
   Architecture:          x86_64
   CPU op-mode(s):        32-bit, 64-bit
   Byte Order:            Little Endian
   CPU(s):                8
   On-line CPU(s) list:   0-7
   Thread(s) per core:    2
   Core(s) per socket:    4
   Socket(s):             1
   NUMA node(s):          1
   Vendor ID:             GenuineIntel
   CPU family:            6
   Model:                 79
   Model name:            Intel(R) Xeon(R) CPU E5-2686 v4 @ 2.30GHz
   Stepping:              1
   CPU MHz:               2699.984
   CPU max MHz:           3000.0000
   CPU min MHz:           1200.0000
   BogoMIPS:              4600.08
   Hypervisor vendor:     Xen
   Virtualization type:   full
   L1d cache:             32K
   L1i cache:             32K
   L2 cache:              256K
   L3 cache:              46080K
   NUMA node0 CPU(s):     0-7
   Flags:                 fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx pdpe1gb rdtscp lm constant_tsc rep_good nopl xtopology nonstop_tsc aperfmperf eagerfpu pni pclmulqdq ssse3 fma cx16 pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand hypervisor lahf_lm abm 3dnowprefetch invpcid_single retpoline kaiser fsgsbase bmi1 hle avx2 smep bmi2 erms invpcid rtm rdseed adx xsaveopt
   ----------Network Test----------
   Setting timeout: 10
   Timing for MXNet: https://github.com/apache/incubator-mxnet, DNS: 0.0040 sec, LOAD: 0.3429 sec.
   Timing for Gluon Tutorial(en): http://gluon.mxnet.io, DNS: 0.0385 sec, LOAD: 0.3615 sec.
   Timing for Gluon Tutorial(cn): https://zh.gluon.ai, DNS: 0.4978 sec, LOAD: 0.3804 sec.
   Timing for FashionMNIST: https://apache-mxnet.s3-accelerate.dualstack.amazonaws.com/gluon/dataset/fashion-mnist/train-labels-idx1-ubyte.gz, DNS: 0.0207 sec, LOAD: 0.1522 sec.
   Timing for PYPI: https://pypi.python.org/pypi/pip, DNS: 0.0027 sec, LOAD: 0.0859 sec.
   Timing for Conda: https://repo.continuum.io/pkgs/free/, DNS: 0.0284 sec, LOAD: 0.0201 sec.
   ```
   
   Package used (Python/R/Scala/Julia):
   I'm using Python
   
   
   ## Minimum reproducible example
   
   MXNet (giving incorrect output):
   
   ```
   import mxnet as mx
   
   data = mx.nd.array(((0,0,0),
                       (0,1,0),
                       (0,0,0)))
   kernel = mx.nd.array(((1,2,3),
                         (4,5,6),
                         (7,8,9)))
   
   data_batch = data.expand_dims(0).expand_dims(0)
   weight = kernel.expand_dims(0).expand_dims(0)
   # initialize and set weight
   conv = mx.gluon.nn.Conv2DTranspose(in_channels=1, channels=1,
                                      kernel_size=(3,3), padding=(2,2),
                                      strides=(2,2), dilation=(2,2))
   conv.initialize()
   conv.weight.set_data(weight)
   print(conv(data_batch))
   ```
   
   ```
   [[[[ 0.  0.  0.  0.  0.]
      [ 0.  1.  0.  2.  3.]
      [ 0.  0.  0.  0.  0.]
      [ 0.  4.  0.  5.  6.]
      [ 0.  7.  0.  8.  9.]]]]
   <NDArray 1x1x5x5 @cpu(0)>
   ```
   
   PyTorch (giving correct output):
   
   ```
   import torch
   
   data = torch.tensor(((0,0,0),
                        (0,1,0),
                        (0,0,0)), dtype=torch.float32)
   kernel = torch.tensor(((1,2,3),
                          (4,5,6),
                          (7,8,9)), dtype=torch.float32)
   
   data_batch = data.expand(1,1,-1,-1)
   weight = kernel.expand(1,1,-1,-1)
   conv = torch.nn.ConvTranspose2d(in_channels=1, out_channels=1,
                                   kernel_size=(3,3), padding=(2,2),
                                   stride=(2,2), dilation=(2,2))
   conv.weight.data = weight
   print(conv(data_batch).round())
   ```
   
   ```
   tensor([[[[ 1.,  0.,  2.,  0.,  3.],
             [ 0.,  0.,  0.,  0.,  0.],
             [ 4.,  0.,  5.,  0.,  6.],
             [ 0.,  0.,  0.,  0.,  0.],
             [ 7.,  0.,  8.,  0.,  9.]]]])
   ```
   

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