Plotting the latent space

1

Hi All

I trained a variational autoencoder, however don’t know how I can plot my latent space. Below you can see my codes that used for defining the class of autoencoder:(I would like to plot the z)

class B_VAE(nn.Module):

def init(self,zdims):
super().init()
self.zdims = zdims
#Encoder layer
self.encoder = nn.Sequential(nn.Conv1d(1,4,kernel_size = 4, stride = 3),
nn.MaxPool1d(kernel_size = 4, stride = 3),
nn.Tanh(),

        nn.Conv1d(4,8,kernel_size=4, stride = 2),
        nn.MaxPool1d(kernel_size = 4,stride = 2),
        nn.Tanh(),
                 
        
        nn.Conv1d(8,12,kernel_size = 4, stride = 2),
        nn.MaxPool1d(kernel_size = 4,stride = 1),
        nn.Tanh(),

        nn.Conv1d(12,16,kernel_size = 4, stride = 1),
        nn.MaxPool1d(kernel_size = 3,stride = 1),
        nn.Tanh())

#Cov FC LAYER
self.fc_mu = nn.Linear(16,self.zdims)
self.fc_std = nn.Linear(16,self.zdims)

#Deconv FC LAYER

self.fc_d = nn.Linear(self.zdims,16)

#Decoder layer
self.decoder = nn.Sequential(nn.ConvTranspose1d(16,12,kernel_size = 5, stride = 2),
        nn.Tanh(),
        

        nn.ConvTranspose1d(12,8,kernel_size = 5,stride = 3),
        nn.Tanh(),
                    

        nn.ConvTranspose1d(8,4,kernel_size= 12,stride = 4),
        nn.Tanh(),

        nn.ConvTranspose1d(4,1,kernel_size = 18, stride = 9),
        nn.Tanh())

def parameterization_trick(self,mu,logvar):

  std = torch.exp(logvar*0.5)
  # sample epslion from N(0,1)
  eps = torch.randn_like(std)
  # sampling now can be done by shifting the eps by (adding) the mean 
    # and scaling it by the variance.
  return mu+eps*std

def encode(self,imgs):

  output = self.encoder(imgs)
  output = output.view(-1,16)
  mu = self.fc_mu(output)
  logvar = self.fc_std(output)
  z = self.parameterization_trick(mu,logvar)
  return mu,logvar,z

def decode(self,z):

  deconv_input = (self.fc_d(z))
  deconv_input = deconv_input.view(-1,16,2)
  reconstructed_img = self.decoder(deconv_input)
  return reconstructed_img

def forward(self,x):
mu,logvar,z = self.encode(x)
reconstructed_img = self.decode(z)
return reconstructed_img, mu, logvar

def loss_disentangled_vae(outputs, imgs, mu, logvar, Beta):
criterion = nn.MSELoss()
recons_loss = criterion(outputs,imgs)
kl = -0.5 * torch.sum(1 + logvar - mu.pow(2) - logvar.exp())
return (recons_loss+(Beta*kl))

Thanks

2

I don’t think there is an easy way to plot a multi-dimensional tensor.
Often your latent vector has >100 dimensions, so you could try to apply some dimensionality reduction techniques such as t-SNE, PCA etc. to be able to plot these tensors in a 2D scatter plot.

1 Like
3

Hi Patrick

Thank you for your comments. I actually use PCA to reduce dim of my latent space and then plot that.
After training my model, I can see that reconstruction become awful :frowning: Actually trained model can not even reconstruct the input roughly.

I would guess that sth should be wrong in my codes. I tried many things however, could not find that. May I ask you to take a quick look to my model and see if you can find my mistake?
zdim = 20
Beta = 3

ps: classic AE gives me perfect result however this one almost gives me nothing.

I appreciate you time,
Wash your hands after reading this massage, :smiley:

Pedram