update doc for pruning algorithms

docs/en_US/Compressor/Overview.md

@@ -21,11 +21,11 @@ Pruning algorithms compress the original network by removing redundant weights o
 | [AGP Pruner](./Pruner.md#agp-pruner) | Automated gradual pruning (To prune, or not to prune: exploring the efficacy of pruning for model compression) [Reference Paper](https://arxiv.org/abs/1710.01878)|
 | [Lottery Ticket Pruner](./Pruner.md#agp-pruner) | The pruning process used by "The Lottery Ticket Hypothesis: Finding Sparse, Trainable Neural Networks". It prunes a model iteratively. [Reference Paper](https://arxiv.org/abs/1803.03635)|
 | [FPGM Pruner](./Pruner.md#fpgm-pruner) | Filter Pruning via Geometric Median for Deep Convolutional Neural Networks Acceleration [Reference Paper](https://arxiv.org/pdf/1811.00250.pdf)|
-| [L1Filter Pruner](./Pruner.md#l1filter-pruner) | Pruning filters with the smallest L1 norm of weights in convolution layers(PRUNING FILTERS FOR EFFICIENT CONVNETS)[Reference Paper](https://arxiv.org/abs/1608.08710) |
+| [L1Filter Pruner](./Pruner.md#l1filter-pruner) | Pruning filters with the smallest L1 norm of weights in convolution layers (Pruning Filters for Efficient Convnets) [Reference Paper](https://arxiv.org/abs/1608.08710) |
 | [L2Filter Pruner](./Pruner.md#l2filter-pruner) | Pruning filters with the smallest L2 norm of weights in convolution layers |
-| [ActivationAPoZRankFilterPruner](./Pruner.md#ActivationAPoZRankFilterPruner) | Pruning filters prunes the filters with the smallest APoZ(average percentage of zeros) of output activations(Network Trimming: A Data-Driven Neuron Pruning Approach towards Efficient Deep Architectures)[Reference Paper](https://arxiv.org/abs/1607.03250) |
-| [ActivationMeanRankFilterPruner](./Pruner.md#ActivationMeanRankFilterPruner) | Pruning filters prunes the filters with the smallest mean value of output activations(Pruning Convolutional Neural Networks for Resource Efficient Inference)[Reference Paper](https://arxiv.org/abs/1611.06440) |
-| [Slim Pruner](./Pruner.md#slim-pruner) | Pruning channels in convolution layers by pruning scaling factors in BN layers(Learning Efficient Convolutional Networks through Network Slimming)[Reference Paper](https://arxiv.org/abs/1708.06519) |
+| [ActivationAPoZRankFilterPruner](./Pruner.md#ActivationAPoZRankFilterPruner) | Pruning filters based on the metric APoZ (average percentage of zeros) which measures the percentage of zeros in activations of (convolutional) layers. [Reference Paper](https://arxiv.org/abs/1607.03250) |
+| [ActivationMeanRankFilterPruner](./Pruner.md#ActivationMeanRankFilterPruner) | Pruning filters based on the metric that calculates the smallest mean value of output activations |
+| [Slim Pruner](./Pruner.md#slim-pruner) | Pruning channels in convolution layers by pruning scaling factors in BN layers(Learning Efficient Convolutional Networks through Network Slimming) [Reference Paper](https://arxiv.org/abs/1708.06519) |
 
 
 **Quantization**

docs/en_US/Compressor/Pruner.md

@@ -1,6 +1,19 @@
 Pruner on NNI Compressor
 ===
 
+Index of supported pruning algorithms
+* [Level Pruner](#level-pruner)
+* [AGP Pruner](#agp-pruner)
+* [Lottery Ticket Hypothesis](#lottery-ticket-hypothesis)
+* [Slim Pruner](#slim-pruner)
+* [Filter Pruners with Weight Rank](#weightrankfilterpruner)
+    * [FPGM Pruner](#fpgm-pruner)
+    * [L1Filter Pruner](#l1filter-pruner)
+    * [L2Filter Pruner](#l2filter-pruner)
+* [Filter Pruners with Activation Rank](#activationrankfilterpruner)
+    * [APoZ Rank Pruner](#activationapozrankfilterpruner)
+    * [Activation Mean Rank Pruner](#activationmeanrankfilterpruner)
+
 ## Level Pruner
 
 This is one basic one-shot pruner: you can set a target sparsity level (expressed as a fraction, 0.6 means we will prune 60%). 
@@ -131,13 +144,43 @@ The above configuration means that there are 5 times of iterative pruning. As th
 * **sparsity:** The final sparsity when the compression is done.
 
 ***
+
+## Slim Pruner
+
+This is an one-shot pruner, In ['Learning Efficient Convolutional Networks through Network Slimming'](https://arxiv.org/pdf/1708.06519.pdf), authors Zhuang Liu, Jianguo Li, Zhiqiang Shen, Gao Huang, Shoumeng Yan and Changshui Zhang.
+
+![](../../img/slim_pruner.png)
+
+> Slim Pruner **prunes channels in the convolution layers by masking corresponding scaling factors in the later BN layers**, L1 regularization on the scaling factors should be applied in batch normalization (BN) layers while training, scaling factors of BN layers are **globally ranked** while pruning, so the sparse model can be automatically found given sparsity.
+
+### Usage
+
+PyTorch code
+
+```python
+from nni.compression.torch import SlimPruner
+config_list = [{ 'sparsity': 0.8, 'op_types': ['BatchNorm2d'] }]
+pruner = SlimPruner(model, config_list)
+pruner.compress()
+```
+
+#### User configuration for Slim Pruner
+
+- **sparsity:** This is to specify the sparsity operations to be compressed to
+- **op_types:** Only BatchNorm2d is supported in Slim Pruner
+
+
 ## WeightRankFilterPruner
 WeightRankFilterPruner is a series of pruners which prune the filters with the smallest importance criterion calculated from the weights in convolution layers to achieve a preset level of network sparsity
 
-### 1, FPGM Pruner
+### FPGM Pruner
 
 This is an one-shot pruner, FPGM Pruner is an implementation of paper [Filter Pruning via Geometric Median for Deep Convolutional Neural Networks Acceleration](https://arxiv.org/pdf/1811.00250.pdf)
 
+FPGMPruner prune filters with the smallest geometric median
+
+ ![](../../img/fpgm_fig1.png)
+
 >Previous works utilized “smaller-norm-less-important” criterion to prune filters with smaller norm values in a convolutional neural network. In this paper, we analyze this norm-based criterion and point out that its effectiveness depends on two requirements that are not always met: (1) the norm deviation of the filters should be large; (2) the minimum norm of the filters should be small. To solve this problem, we propose a novel filter pruning method, namely Filter Pruning via Geometric Median (FPGM), to compress the model regardless of those two requirements. Unlike previous methods, FPGM compresses CNN models by pruning filters with redundancy, rather than those with “relatively less” importance.
 
 #### Usage
@@ -181,9 +224,9 @@ You can view example for more information
 
 ***
 
-### 2, L1Filter Pruner
+### L1Filter Pruner
 
-This is an one-shot pruner, In ['PRUNING FILTERS FOR EFFICIENT CONVNETS'](https://arxiv.org/abs/1608.08710), authors Hao Li, Asim Kadav, Igor Durdanovic, Hanan Samet and Hans Peter Graf.
+This is an one-shot pruner, In ['PRUNING FILTERS FOR EFFICIENT CONVNETS'](https://arxiv.org/abs/1608.08710), authors Hao Li, Asim Kadav, Igor Durdanovic, Hanan Samet and Hans Peter Graf. The reproduced experiment results can be found [here](l1filterpruner.md)
 
 ![](../../img/l1filter_pruner.png)
 
@@ -217,9 +260,9 @@ pruner.compress()
 
 ***
 
-### 3, L2Filter Pruner
+### L2Filter Pruner
 
-This is a structured pruning algorithm that prunes the filters with the smallest L2 norm of the weights.
+This is a structured pruning algorithm that prunes the filters with the smallest L2 norm of the weights. It is implemented as a one-shot pruner.
 
 #### Usage
 
@@ -240,9 +283,13 @@ pruner.compress()
 ## ActivationRankFilterPruner
 ActivationRankFilterPruner is a series of pruners which prune the filters with the smallest importance criterion calculated from the output activations of convolution layers to achieve a preset level of network sparsity
 
-### 1, ActivationAPoZRankFilterPruner
+### ActivationAPoZRankFilterPruner
+
+We implemented it as a one-shot pruner, it prunes convolutional layers based on the criterion `APoZ` which is explained in the paper [Network Trimming: A Data-Driven Neuron Pruning Approach towards Efficient Deep Architectures](https://arxiv.org/abs/1607.03250). Iterative pruning based on `APoZ` will be supported in future release.
 
-This is an one-shot pruner, ActivationAPoZRankFilterPruner is an implementation of paper [Network Trimming: A Data-Driven Neuron Pruning Approach towards Efficient Deep Architectures](https://arxiv.org/abs/1607.03250)
+The APoZ is defined as:
+
+![](../../img/apoz.png)
 
 #### Usage
 
@@ -269,9 +316,9 @@ You can view example for more information
 
 ***
 
-### 2, ActivationMeanRankFilterPruner
+### ActivationMeanRankFilterPruner
 
-This is an one-shot pruner, ActivationMeanRankFilterPruner is an implementation of paper [Pruning Convolutional Neural Networks for Resource Efficient Inference](https://arxiv.org/abs/1611.06440)
+We implemented it as a one-shot pruner, it prunes convolutional layers based on the criterion `mean activation` which is explained in section 2.2 of the paper[Pruning Convolutional Neural Networks for Resource Efficient Inference](https://arxiv.org/abs/1611.06440). Other pruning criteria mentioned in this paper will be supported in future release.
 
 #### Usage
 
@@ -296,28 +343,4 @@ You can view example for more information
 - **sparsity:** How much percentage of convolutional filters are to be pruned.
 - **op_types:** Only Conv2d is supported in ActivationMeanRankFilterPruner
 
-***
-
-## Slim Pruner
-
-This is an one-shot pruner, In ['Learning Efficient Convolutional Networks through Network Slimming'](https://arxiv.org/pdf/1708.06519.pdf), authors Zhuang Liu, Jianguo Li, Zhiqiang Shen, Gao Huang, Shoumeng Yan and Changshui Zhang.
-
-![](../../img/slim_pruner.png)
-
-> Slim Pruner **prunes channels in the convolution layers by masking corresponding scaling factors in the later BN layers**, L1 regularization on the scaling factors should be applied in batch normalization (BN) layers while training, scaling factors of BN layers are **globally ranked** while pruning, so the sparse model can be automatically found given sparsity.
-
-### Usage
-
-PyTorch code
-
-```python
-from nni.compression.torch import SlimPruner
-config_list = [{ 'sparsity': 0.8, 'op_types': ['BatchNorm2d'] }]
-pruner = SlimPruner(model, config_list)
-pruner.compress()
-```
-
-#### User configuration for Slim Pruner
-
-- **sparsity:** This is to specify the sparsity operations to be compressed to
-- **op_types:** Only BatchNorm2d is supported in Slim Pruner
+***

docs/en_US/Compressor/WeightRankFilterPruner.md → docs/en_US/Compressor/l1filterpruner.md

@@ -1,19 +1,7 @@
-WeightRankFilterPruner on NNI Compressor
+L1FilterPruner on NNI
 ===
 
-## 1. Introduction
-
-WeightRankFilterPruner is a series of pruners which prune filters according to some importance criterion calculated from the filters' weight.
-
-|     Pruner     |    Importance criterion     |                       Reference paper                        |
-| :------------: | :-------------------------: | :----------------------------------------------------------: |
-| L1FilterPruner |     L1 norm of weights      | [PRUNING FILTERS FOR EFFICIENT CONVNETS](https://arxiv.org/abs/1608.08710) |
-| L2FilterPruner |     L2 norm of weights      |                                                              |
-|   FPGMPruner   | Geometric Median of weights | [Filter Pruning via Geometric Median for Deep Convolutional Neural Networks Acceleration](https://arxiv.org/pdf/1811.00250.pdf) |
-
-## 2. Pruners
-
-### L1FilterPruner
+## Introduction
 
 L1FilterPruner is a general structured pruning algorithm for pruning filters in the convolutional layers.
 
@@ -33,37 +21,7 @@ In ['PRUNING FILTERS FOR EFFICIENT CONVNETS'](https://arxiv.org/abs/1608.08710),
 > 4. A new kernel matrix is created for both the ![](http://latex.codecogs.com/gif.latex?i)th and ![](http://latex.codecogs.com/gif.latex?i+1)th layers, and the remaining kernel
 >      weights are copied to the new model.
 
-### L2FilterPruner
-
-L2FilterPruner is similar to L1FilterPruner, but only replace the importance criterion from L1 norm to L2 norm
-
-### FPGMPruner
-
-Yang He, Ping Liu, Ziwei Wang, Zhilan Hu, Yi Yang
-
-"[Filter Pruning via Geometric Median for Deep Convolutional Neural Networks Acceleration](https://arxiv.org/abs/1811.00250)", CVPR 2019.
-
-FPGMPruner prune filters with the smallest geometric median
-
- ![](../../img/fpgm_fig1.png)
-
-## 3. Usage
-
-PyTorch code
-
-```
-from nni.compression.torch import L1FilterPruner
-config_list = [{ 'sparsity': 0.8, 'op_types': ['Conv2d'], 'op_names': ['conv1', 'conv2'] }]
-pruner = L1FilterPruner(model, config_list)
-pruner.compress()
-```
-
-#### User configuration for L1Filter Pruner
-
-- **sparsity:** This is to specify the sparsity operations to be compressed to
-- **op_types:** Only Conv2d is supported in L1Filter Pruner
-
-## 4. Experiment
+## Experiment
 
 We implemented one of the experiments in ['PRUNING FILTERS FOR EFFICIENT CONVNETS'](https://arxiv.org/abs/1608.08710) with **L1FilterPruner**, we pruned **VGG-16** for CIFAR-10 to **VGG-16-pruned-A** in the paper, in which $64\%$ parameters are pruned. Our experiments results are as follows: