From 3015941b5c61b686161701887a8618f5f77044bb Mon Sep 17 00:00:00 2001
From: Alby M <1473644+Linux-cpp-lisp@users.noreply.github.com>
Date: Tue, 20 Apr 2021 12:16:39 -0600
Subject: Option to keep parameters reference in `ExponentialMovingAverage`
 (#5)

---
 tests/test_ema.py | 64 ++++++++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 51 insertions(+), 13 deletions(-)

(limited to 'tests')

diff --git a/tests/test_ema.py b/tests/test_ema.py
index 6d7e43e..ad6ee37 100644
--- a/tests/test_ema.py
+++ b/tests/test_ema.py
@@ -7,7 +7,8 @@ from torch_ema import ExponentialMovingAverage
 
 @pytest.mark.parametrize("decay", [0.995, 0.9])
 @pytest.mark.parametrize("use_num_updates", [True, False])
-def test_val_error(decay, use_num_updates):
+@pytest.mark.parametrize("explicit_params", [True, False])
+def test_val_error(decay, use_num_updates, explicit_params):
     """Confirm that EMA validation error is lower than raw validation error."""
     torch.manual_seed(0)
     x_train = torch.rand((100, 10))
@@ -30,27 +31,37 @@ def test_val_error(decay, use_num_updates):
         optimizer.zero_grad()
         loss.backward()
         optimizer.step()
-        ema.update(model.parameters())
+        if explicit_params:
+            ema.update(model.parameters())
+        else:
+            ema.update()
 
     # Validation: original
     model.eval()
     logits = model(x_val)
     loss_orig = torch.nn.functional.cross_entropy(logits, y_val)
-    print(f"Original loss: {loss_orig}")
 
     # Validation: with EMA
     # First save original parameters before replacing with EMA version
-    ema.store(model.parameters())
+    if explicit_params:
+        ema.store(model.parameters())
+    else:
+        ema.store()
     # Copy EMA parameters to model
-    ema.copy_to(model.parameters())
+    if explicit_params:
+        ema.copy_to(model.parameters())
+    else:
+        ema.copy_to()
     logits = model(x_val)
     loss_ema = torch.nn.functional.cross_entropy(logits, y_val)
 
-    print(f"EMA loss: {loss_ema}")
     assert loss_ema < loss_orig, "EMA loss wasn't lower"
 
     # Test restore
-    ema.restore(model.parameters())
+    if explicit_params:
+        ema.restore(model.parameters())
+    else:
+        ema.restore()
     model.eval()
     logits = model(x_val)
     loss_orig2 = torch.nn.functional.cross_entropy(logits, y_val)
@@ -60,7 +71,8 @@ def test_val_error(decay, use_num_updates):
 
 @pytest.mark.parametrize("decay", [0.995, 0.9, 0.0, 1.0])
 @pytest.mark.parametrize("use_num_updates", [True, False])
-def test_store_restore(decay, use_num_updates):
+@pytest.mark.parametrize("explicit_params", [True, False])
+def test_store_restore(decay, use_num_updates, explicit_params):
     model = torch.nn.Linear(10, 2)
     ema = ExponentialMovingAverage(
         model.parameters(),
@@ -68,15 +80,22 @@ def test_store_restore(decay, use_num_updates):
         use_num_updates=use_num_updates
     )
     orig_weight = model.weight.clone().detach()
-    ema.store(model.parameters())
+    if explicit_params:
+        ema.store(model.parameters())
+    else:
+        ema.store()
     with torch.no_grad():
         model.weight.uniform_(0.0, 1.0)
-    ema.restore(model.parameters())
+    if explicit_params:
+        ema.restore(model.parameters())
+    else:
+        ema.restore()
     assert torch.all(model.weight == orig_weight)
 
 
 @pytest.mark.parametrize("decay", [0.995, 0.9, 0.0, 1.0])
-def test_update(decay):
+@pytest.mark.parametrize("explicit_params", [True, False])
+def test_update(decay, explicit_params):
     model = torch.nn.Linear(10, 2, bias=False)
     with torch.no_grad():
         model.weight.fill_(0.0)
@@ -87,10 +106,29 @@ def test_update(decay):
     )
     with torch.no_grad():
         model.weight.fill_(1.0)
-    ema.update(model.parameters())
+    if explicit_params:
+        ema.update(model.parameters())
+    else:
+        ema.update()
     assert torch.all(model.weight == 1.0), "ema.update changed model weights"
-    ema.copy_to(model.parameters())
+    if explicit_params:
+        ema.copy_to(model.parameters())
+    else:
+        ema.copy_to()
     assert torch.allclose(
         model.weight,
         torch.full(size=(1,), fill_value=(1.0 - decay))
     ), "average was wrong"
+
+
+def test_explicit_params():
+    model = torch.nn.Linear(10, 2)
+    with torch.no_grad():
+        model.weight.fill_(0.0)
+    ema = ExponentialMovingAverage(model.parameters(), decay=0.9)
+    model2 = torch.nn.Linear(10, 2)
+    with torch.no_grad():
+        model2.weight.fill_(1.0)
+    ema.update(model2.parameters())
+    ema.copy_to()
+    assert not torch.all(model.weight == 0.0)
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