add pruner unit test (#1771)

* add pruner unit test
* modify pruners compatible with torch0.4.1

docs/en_US/Compressor/SlimPruner.md

@@ -34,6 +34,6 @@ We implemented one of the experiments in ['Learning Efficient Convolutional Netw
 | Model         | Error(paper/ours) | Parameters | Pruned    |
 | ------------- | ----------------- | ---------- | --------- |
 | VGGNet        | 6.34/6.40     | 20.04M   |           |
-| Pruned-VGGNet | 6.20/6.39     | 2.03M    | 88.5% |
+| Pruned-VGGNet | 6.20/6.26     | 2.03M    | 88.5% |
 
 The experiments code can be found at [examples/model_compress]( https://github.com/microsoft/nni/tree/master/examples/model_compress/)

examples/model_compress/slim_pruner_torch_vgg19.py

@@ -169,7 +169,7 @@ def main():
     new_model.to(device)
     new_model.load_state_dict(torch.load('pruned_vgg19_cifar10.pth'))
     test(new_model, device, test_loader)
-    # top1 = 93.61%
+    # top1 = 93.74%
 
 
 if __name__ == '__main__':

src/sdk/pynni/nni/compression/torch/builtin_pruners.py

@@ -47,7 +47,7 @@ class LevelPruner(Pruner):
             k = int(weight.numel() * config['sparsity'])
             if k == 0:
                 return torch.ones(weight.shape).type_as(weight)
-            threshold = torch.topk(w_abs.view(-1), k, largest=False).values.max()
+            threshold = torch.topk(w_abs.view(-1), k, largest=False)[0].max()
             mask = torch.gt(w_abs, threshold).type_as(weight)
             self.mask_dict.update({op_name: mask})
             self.if_init_list.update({op_name: False})
@@ -108,7 +108,7 @@ class AGP_Pruner(Pruner):
                 return mask
             # if we want to generate new mask, we should update weigth first
             w_abs = weight.abs() * mask
-            threshold = torch.topk(w_abs.view(-1), k, largest=False).values.max()
+            threshold = torch.topk(w_abs.view(-1), k, largest=False)[0].max()
             new_mask = torch.gt(w_abs, threshold).type_as(weight)
             self.mask_dict.update({op_name: new_mask})
             self.if_init_list.update({op_name: False})
@@ -336,7 +336,7 @@ class L1FilterPruner(Pruner):
             if k == 0:
                 return torch.ones(weight.shape).type_as(weight)
             w_abs_structured = w_abs.view(filters, -1).sum(dim=1)
-            threshold = torch.topk(w_abs_structured.view(-1), k, largest=False).values.max()
+            threshold = torch.topk(w_abs_structured.view(-1), k, largest=False)[0].max()
             mask = torch.gt(w_abs_structured, threshold)[:, None, None, None].expand_as(weight).type_as(weight)
         finally:
             self.mask_dict.update({layer.name: mask})
@@ -370,10 +370,10 @@ class SlimPruner(Pruner):
         config = config_list[0]
         for (layer, config) in self.detect_modules_to_compress():
             assert layer.type == 'BatchNorm2d', 'SlimPruner only supports 2d batch normalization layer pruning'
-            weight_list.append(layer.module.weight.data.clone())
+            weight_list.append(layer.module.weight.data.abs().clone())
         all_bn_weights = torch.cat(weight_list)
         k = int(all_bn_weights.shape[0] * config['sparsity'])
-        self.global_threshold = torch.topk(all_bn_weights.view(-1), k, largest=False).values.max()
+        self.global_threshold = torch.topk(all_bn_weights.view(-1), k, largest=False)[0].max()
 
     def calc_mask(self, layer, config):
         """

src/sdk/pynni/tests/test_compressor.py

@@ -8,6 +8,7 @@ import nni.compression.torch as torch_compressor
 if tf.__version__ >= '2.0':
     import nni.compression.tensorflow as tf_compressor
 
+
 def get_tf_model():
     model = tf.keras.models.Sequential([
         tf.keras.layers.Conv2D(filters=5, kernel_size=7, input_shape=[28, 28, 1], activation='relu', padding="SAME"),
@@ -20,42 +21,49 @@ def get_tf_model():
         tf.keras.layers.Dense(units=10, activation='softmax'),
     ])
     model.compile(loss="sparse_categorical_crossentropy",
-        optimizer=tf.keras.optimizers.SGD(lr=1e-3),
-        metrics=["accuracy"])
+                  optimizer=tf.keras.optimizers.SGD(lr=1e-3),
+                  metrics=["accuracy"])
     return model
 
+
 class TorchModel(torch.nn.Module):
     def __init__(self):
         super().__init__()
         self.conv1 = torch.nn.Conv2d(1, 5, 5, 1)
+        self.bn1 = torch.nn.BatchNorm2d(5)
         self.conv2 = torch.nn.Conv2d(5, 10, 5, 1)
+        self.bn2 = torch.nn.BatchNorm2d(10)
         self.fc1 = torch.nn.Linear(4 * 4 * 10, 100)
         self.fc2 = torch.nn.Linear(100, 10)
 
     def forward(self, x):
-        x = F.relu(self.conv1(x))
+        x = F.relu(self.bn1(self.conv1(x)))
         x = F.max_pool2d(x, 2, 2)
-        x = F.relu(self.conv2(x))
+        x = F.relu(self.bn2(self.conv2(x)))
         x = F.max_pool2d(x, 2, 2)
         x = x.view(-1, 4 * 4 * 10)
         x = F.relu(self.fc1(x))
         x = self.fc2(x)
         return F.log_softmax(x, dim=1)
 
+
 def tf2(func):
     def test_tf2_func(*args):
         if tf.__version__ >= '2.0':
             func(*args)
+
     return test_tf2_func
 
-k1 = [[1]*3]*3
-k2 = [[2]*3]*3
-k3 = [[3]*3]*3
-k4 = [[4]*3]*3
-k5 = [[5]*3]*3
+
+k1 = [[1] * 3] * 3
+k2 = [[2] * 3] * 3
+k3 = [[3] * 3] * 3
+k4 = [[4] * 3] * 3
+k5 = [[5] * 3] * 3
 
 w = [[k1, k2, k3, k4, k5]] * 10
 
+
 class CompressorTestCase(TestCase):
     def test_torch_level_pruner(self):
         model = TorchModel()
@@ -74,7 +82,7 @@ class CompressorTestCase(TestCase):
             'quant_bits': {
                 'weight': 8,
             },
-            'op_types':['Conv2d', 'Linear']
+            'op_types': ['Conv2d', 'Linear']
         }]
         torch_compressor.NaiveQuantizer(model, configure_list).compress()
 
@@ -133,6 +141,73 @@ class CompressorTestCase(TestCase):
 
         assert all(masks.sum((0, 2, 3)) == np.array([90., 0., 0., 0., 90.]))
 
+    def test_torch_l1filter_pruner(self):
+        """
+        Filters with the minimum sum of the weights' L1 norm are pruned in this paper:
+        PRUNING FILTERS FOR EFFICIENT CONVNETS,
+        https://arxiv.org/abs/1608.08710
+
+        So if sparsity is 0.2, the expected masks should mask out filter 0, this can be verified through:
+        `all(torch.sum(mask1, (1, 2, 3)).numpy() == np.array([0., 27., 27., 27., 27.]))`
+
+        If sparsity is 0.6, the expected masks should mask out filter 0,1,2, this can be verified through:
+        `all(torch.sum(mask2, (1, 2, 3)).numpy() == np.array([0., 0., 0., 27., 27.]))`
+        """
+        w = np.array([np.zeros((3, 3, 3)), np.ones((3, 3, 3)), np.ones((3, 3, 3)) * 2,
+                      np.ones((3, 3, 3)) * 3, np.ones((3, 3, 3)) * 4])
+        model = TorchModel()
+        config_list = [{'sparsity': 0.2, 'op_names': ['conv1']}, {'sparsity': 0.6, 'op_names': ['conv2']}]
+        pruner = torch_compressor.L1FilterPruner(model, config_list)
+
+        model.conv1.weight.data = torch.tensor(w).float()
+        model.conv2.weight.data = torch.tensor(w).float()
+        layer1 = torch_compressor.compressor.LayerInfo('conv1', model.conv1)
+        mask1 = pruner.calc_mask(layer1, config_list[0])
+        layer2 = torch_compressor.compressor.LayerInfo('conv2', model.conv2)
+        mask2 = pruner.calc_mask(layer2, config_list[1])
+        assert all(torch.sum(mask1, (1, 2, 3)).numpy() == np.array([0., 27., 27., 27., 27.]))
+        assert all(torch.sum(mask2, (1, 2, 3)).numpy() == np.array([0., 0., 0., 27., 27.]))
+
+    def test_torch_slim_pruner(self):
+        """
+        Scale factors with minimum l1 norm in the BN layers are pruned in this paper:
+        Learning Efficient Convolutional Networks through Network Slimming,
+        https://arxiv.org/pdf/1708.06519.pdf
+
+        So if sparsity is 0.2, the expected masks should mask out channel 0, this can be verified through:
+        `all(mask1.numpy() == np.array([0., 1., 1., 1., 1.]))`
+        `all(mask2.numpy() == np.array([0., 1., 1., 1., 1.]))`
+
+        If sparsity is 0.6, the expected masks should mask out channel 0,1,2, this can be verified through:
+        `all(mask1.numpy() == np.array([0., 0., 0., 1., 1.]))`
+        `all(mask2.numpy() == np.array([0., 0., 0., 1., 1.]))`
+        """
+        w = np.array([0, 1, 2, 3, 4])
+        model = TorchModel()
+        config_list = [{'sparsity': 0.2, 'op_types': ['BatchNorm2d']}]
+        model.bn1.weight.data = torch.tensor(w).float()
+        model.bn2.weight.data = torch.tensor(-w).float()
+        pruner = torch_compressor.SlimPruner(model, config_list)
+
+        layer1 = torch_compressor.compressor.LayerInfo('bn1', model.bn1)
+        mask1 = pruner.calc_mask(layer1, config_list[0])
+        layer2 = torch_compressor.compressor.LayerInfo('bn2', model.bn2)
+        mask2 = pruner.calc_mask(layer2, config_list[0])
+        assert all(mask1.numpy() == np.array([0., 1., 1., 1., 1.]))
+        assert all(mask2.numpy() == np.array([0., 1., 1., 1., 1.]))
+
+        config_list = [{'sparsity': 0.6, 'op_types': ['BatchNorm2d']}]
+        model.bn1.weight.data = torch.tensor(w).float()
+        model.bn2.weight.data = torch.tensor(w).float()
+        pruner = torch_compressor.SlimPruner(model, config_list)
+
+        layer1 = torch_compressor.compressor.LayerInfo('bn1', model.bn1)
+        mask1 = pruner.calc_mask(layer1, config_list[0])
+        layer2 = torch_compressor.compressor.LayerInfo('bn2', model.bn2)
+        mask2 = pruner.calc_mask(layer2, config_list[0])
+        assert all(mask1.numpy() == np.array([0., 0., 0., 1., 1.]))
+        assert all(mask2.numpy() == np.array([0., 0., 0., 1., 1.]))
+
 
 if __name__ == '__main__':
     main()