+import svrt
+
+labels = torch.LongTensor(12).zero_()
+labels.narrow(0, 0, labels.size(0)//2).fill_(1)
+
+x = svrt.generate_vignettes(4, labels)
+
+print('compression factor {:f}'.format(x.storage().size() / svrt.compress(x.storage()).size()))
+
+x = x.view(x.size(0), 1, x.size(1), x.size(2))
+
+x.div_(255)