Paddle tutorial (#427)

demo/demo_en.rst

@@ -7,6 +7,7 @@ here are some examples for different platforms.
 .. toctree::
     :maxdepth: 1
 
+    paddle/TUTORIAL_EN.md
     keras/TUTORIAL_EN.md
     mxnet/TUTORIAL_EN.md
     pytorch/TUTORIAL_EN.md
\ No newline at end of file

demo/paddle/TUTORIAL_EN.md

+# How to use VisualDL in PaddlePaddle
+
+Here we will show you how to use VisualDL with PaddlePaddle so that you can visualize the training process of PaddlePaddle.
+We will use the Paddle Convolution Neural Network to train the [Cifar10](https://www.cs.toronto.edu/~kriz/cifar.html) dataset as an example.
+
+This example is the modification with fluid PaddlePaddle's API from this official Paddle Book
+[Example](https://github.com/PaddlePaddle/book/tree/develop/03.image_classification)
+
+The full demonstration code can be downloaded in [here](https://github.com/PaddlePaddle/VisualDL/blob/develop/demo/paddle/paddle_cifar10.py).
+
+The script is based on Paddle v2 0.11. You can do ```pip install paddlepaddle``` or ```docker pull paddlepaddle/paddle:0.11.0```. Notice Paddle does not support Python3 yet and protobuf version needs to be 3.5+. For details, please
+follow Paddle's installation guide [here](http://paddlepaddle.org/docs/0.11.0/documentation/en/getstarted/build_and_install/index_en.html)
+
+
+First we initialize Loggers for different types of record as follows:
+
+```python
+# create VisualDL logger and directory
+logdir = "./tmp"
+logwriter = LogWriter(logdir, sync_cycle=10)
+
+# create 'train' run
+with logwriter.mode("train") as writer:
+    # create 'loss' scalar tag to keep track of loss function
+    loss_scalar = writer.scalar("loss")
+
+with logwriter.mode("train") as writer:
+    acc_scalar = writer.scalar("acc")
+
+num_samples = 4
+with logwriter.mode("train") as writer:
+    conv_image = writer.image("conv_image", num_samples, 1) #show 4 samples for every 1 step
+    input_image = writer.image("input_image", num_samples, 1)
+
+with logwriter.mode("train") as writer:
+    param1_histgram = writer.histogram("param1", 100) #100 buckets, e.g 100 data sets in a histograms
+
+```
+
+We use Paddle v2 Fluid APIs to define our VGG CNN model as follows:
+
+```python
+def vgg16_bn_drop(input):
+    def conv_block(input, num_filter, groups, dropouts):
+        return fluid.nets.img_conv_group(
+            input=input,
+            pool_size=2,
+            pool_stride=2,
+            conv_num_filter=[num_filter] * groups,
+            conv_filter_size=3,
+            conv_act='relu',
+            conv_with_batchnorm=True,
+            conv_batchnorm_drop_rate=dropouts,
+            pool_type='max')
+
+    conv1 = conv_block(input, 64, 2, [0.3, 0])
+    conv2 = conv_block(conv1, 128, 2, [0.4, 0])
+    conv3 = conv_block(conv2, 256, 3, [0.4, 0.4, 0])
+    conv4 = conv_block(conv3, 512, 3, [0.4, 0.4, 0])
+    conv5 = conv_block(conv4, 512, 3, [0.4, 0.4, 0])
+
+    drop = fluid.layers.dropout(x=conv5, dropout_prob=0.5)
+    fc1 = fluid.layers.fc(input=drop, size=512, act=None)
+    bn = fluid.layers.batch_norm(input=fc1, act='relu')
+    drop2 = fluid.layers.dropout(x=bn, dropout_prob=0.5)
+    fc2 = fluid.layers.fc(input=drop2, size=512, act=None)
+    return fc2, conv1
+
+
+classdim = 10
+data_shape = [3, 32, 32]
+
+images = fluid.layers.data(name='pixel', shape=data_shape, dtype='float32')
+label = fluid.layers.data(name='label', shape=[1], dtype='int64')
+
+net, conv1 = vgg16_bn_drop(images)
+
+predict = fluid.layers.fc(
+    input=net,
+    size=classdim,
+    act='softmax',
+    param_attr=ParamAttr(name="param1", initializer=NormalInitializer()))
+cost = fluid.layers.cross_entropy(input=predict, label=label)
+avg_cost = fluid.layers.mean(x=cost)
+
+optimizer = fluid.optimizer.Adam(learning_rate=0.001)
+opts = optimizer.minimize(avg_cost)
+
+accuracy = fluid.evaluator.Accuracy(input=predict, label=label)
+
+BATCH_SIZE = 16
+PASS_NUM = 1
+
+train_reader = paddle.batch(
+    paddle.reader.shuffle(paddle.dataset.cifar.train10(), buf_size=128 * 10),
+    batch_size=BATCH_SIZE)
+
+place = fluid.CPUPlace()
+exe = fluid.Executor(place)
+feeder = fluid.DataFeeder(place=place, feed_list=[images, label])
+exe.run(fluid.default_startup_program())
+```
+
+Then we start to train and use VisualDL to record data at the same time.
+
+
+```python
+for pass_id in range(PASS_NUM):
+    accuracy.reset(exe)
+    for data in train_reader():
+        loss, conv1_out, param1, acc = exe.run(
+            fluid.default_main_program(),
+            feed=feeder.feed(data),
+            fetch_list=[avg_cost, conv1, param1_var] + accuracy.metrics)
+        pass_acc = accuracy.eval(exe)
+
+        # all code below is for VisualDL
+
+        # start picking sample from beginning
+        if sample_num == 0:
+            input_image.start_sampling()
+            conv_image.start_sampling()
+
+        idx1 = input_image.is_sample_taken()
+        idx2 = conv_image.is_sample_taken()
+        assert idx1 == idx2
+        idx = idx1
+        if idx != -1:
+            image_data = data[0][0]
+            # reshape the image to 32x32 and 3 channels
+            input_image_data = np.transpose(
+                image_data.reshape(data_shape), axes=[1, 2, 0])
+            # add sample to VisualDL Image Writer to view input image
+            input_image.set_sample(idx, input_image_data.shape,
+                                   input_image_data.flatten())
+
+
+            conv_image_data = conv1_out[0][0]
+            # add sample to view conv image
+            conv_image.set_sample(idx, conv_image_data.shape,
+                                  conv_image_data.flatten())
+
+            sample_num += 1
+            # when we have enough samples, call finish sampling()
+            if sample_num % num_samples == 0:
+                input_image.finish_sampling()
+                conv_image.finish_sampling()
+                sample_num = 0
+
+        # add record for loss and accuracy to scalar
+        loss_scalar.add_record(step, loss)
+        acc_scalar.add_record(step, acc)
+        param1_histgram.add_record(step, param1.flatten())
+
+        print("loss:" + str(loss) + " acc:" + str(acc) + " pass_acc:" + str(
+            pass_acc))
+        step += 1
+```
+
+After the training, launch VisualDL and here is the results.
+The scalar diagram of the accuracy and loss is as follows:
+
+<p align=center>
+<img width="70%" src="https://github.com/daming-lu/large_files/blob/master/paddle_demo_figs/paddle_scalar.png?raw=true" />
+</p>
+
+The 4 samples of input image and the convolution layer image after the training are as follows:
+
+<p align=center>
+<img width="70%" src="https://github.com/daming-lu/large_files/blob/master/paddle_demo_figs/paddle_image.png?raw=true" />
+</p>