Merge branch 'master' of https://github.com/williamFalcon/pytorch-lightning

README.md

@@ -40,21 +40,24 @@ With lightning, you guarantee those parts of your code work so you can focus on
 To use lightning do 2 things:  
 1. [Define a LightningModel](https://williamfalcon.github.io/pytorch-lightning/LightningModule/RequiredTrainerInterface/)         
 ```python
-import pytorch_lightning as ptl
+import os
 import torch
 from torch.nn import functional as F
 from torch.utils.data import DataLoader
 from torchvision.datasets import MNIST
+import torchvision.transforms as transforms
+
+import pytorch_lightning as ptl
 
 class CoolModel(ptl.LightningModule):
 
-    def __init(self):
+    def __init__(self):
         super(CoolModel, self).__init__()
         # not the best model...
         self.l1 = torch.nn.Linear(28 * 28, 10)
 
     def forward(self, x):
-        return torch.relu(self.l1(x))
+        return torch.relu(self.l1(x.view(x.size(0), -1)))
 
     def my_loss(self, y_hat, y):
         return F.cross_entropy(y_hat, y)
@@ -62,7 +65,7 @@ class CoolModel(ptl.LightningModule):
     def training_step(self, batch, batch_nb):
         x, y = batch
         y_hat = self.forward(x)
-        return {'tng_loss': self.my_loss(y_hat, y)}
+        return {'loss': self.my_loss(y_hat, y)}
 
     def validation_step(self, batch, batch_nb):
         x, y = batch
@@ -70,23 +73,23 @@ class CoolModel(ptl.LightningModule):
         return {'val_loss': self.my_loss(y_hat, y)}
 
     def validation_end(self, outputs):
-        avg_loss = torch.stack([x for x in outputs['val_loss']]).mean()
-        return avg_loss
+        avg_loss = torch.stack([x['val_loss'] for x in outputs]).mean()
+        return {'avg_val_loss': avg_loss}
 
     def configure_optimizers(self):
         return [torch.optim.Adam(self.parameters(), lr=0.02)]
 
     @ptl.data_loader
     def tng_dataloader(self):
-        return DataLoader(MNIST('path/to/save', train=True), batch_size=32)
+        return DataLoader(MNIST(os.getcwd(), train=True, download=True, transform=transforms.ToTensor()), batch_size=32)
 
     @ptl.data_loader
     def val_dataloader(self):
-        return DataLoader(MNIST('path/to/save', train=False), batch_size=32)
+        return DataLoader(MNIST(os.getcwd(), train=True, download=True, transform=transforms.ToTensor()), batch_size=32)
 
     @ptl.data_loader
     def test_dataloader(self):
-        return DataLoader(MNIST('path/to/save', train=False), batch_size=32)
+        return DataLoader(MNIST(os.getcwd(), train=True, download=True, transform=transforms.ToTensor()), batch_size=32)
 ```
 
 2. Fit with a [trainer](https://williamfalcon.github.io/pytorch-lightning/Trainer/)    
@@ -95,15 +98,23 @@ from pytorch_lightning import Trainer
 from test_tube import Experiment
 
 model = CoolModel()
+exp = Experiment(save_dir=os.getcwd())
 
-# fit on 32 gpus across 4 nodes
-exp = Experiment(save_dir='some/dir')
-trainer = Trainer(experiment=exp, nb_gpu_nodes=4, gpus=[0,1,2,3,4,5,6,7])
+# train on cpu using only 10% of the data (for demo purposes)
+trainer = Trainer(experiment=exp, max_nb_epochs=1, train_percent_check=0.1)
 
+# train on 4 gpus
+# trainer = Trainer(experiment=exp, max_nb_epochs=1, gpus=[0, 1, 2, 3])
+
+# train on 32 gpus across 4 nodes (make sure to submit appropriate SLURM job)
+# trainer = Trainer(experiment=exp, max_nb_epochs=1, gpus=[0, 1, 2, 3, 4, 5, 6, 7], nb_gpu_nodes=4)
+
+# train (1 epoch only here for demo)
 trainer.fit(model)
 
-# see all experiment metrics here
-# tensorboard --log_dir some/dir   
+# view tensorflow logs 
+print(f'View tensorboard logs by running\ntensorboard --logdir {os.getcwd()}')
+print('and going to http://localhost:6006 on your browser')
 ```
 
 
@@ -305,4 +316,4 @@ python multi_node_cluster_template.py --nb_gpu_nodes 4 --gpus '0,1,2,3,4,5,6,7'
 If you can't wait for the next release, install the most up to date code with:  
 ```bash
 pip install git+https://github.com/williamFalcon/pytorch-lightning.git@master --upgrade
-```
+```