use train_config

example_mnist.py

@@ -11,8 +11,6 @@ sys.path.insert(0, os.path.expanduser('~/.local/lib/python2.7/site-packages'))
 
 import tensorflow as tf
 import numpy as np
-from itertools import count
-
 
 from layers import *
 from utils import *
@@ -20,23 +18,21 @@ from dataflow.dataset import Mnist
 from dataflow import *
 
 IMAGE_SIZE = 28
-NUM_CLASS = 10
-batch_size = 128
 LOG_DIR = 'train_log'
 
 def get_model(inputs):
     """
     Args:
         inputs: a list of input variable,
-        e.g.: [input, label] with:
-            input: bx28x28
-            label: bx1 integer
+        e.g.: [input_var, label_var] with:
+            input_var: bx28x28
+            label_var: bx1 integer
     Returns:
         (outputs, cost)
         outputs: a list of output variable
         cost: scalar variable
     """
-    # use this dropout variable! it will be set to 1 at test time
+    # use this variable in dropout! Tensorpack will automatically set it to 1 at test time
     keep_prob = tf.placeholder(tf.float32, shape=tuple(), name=DROPOUT_PROB_OP_NAME)
 
     input, label = inputs
@@ -62,7 +58,7 @@ def get_model(inputs):
     fc1 = FullyConnected('lr', fc0, out_dim=10)
     prob = tf.nn.softmax(fc1, name='output')
 
-    y = one_hot(label, NUM_CLASS)
+    y = one_hot(label, 10)
     cost = tf.nn.softmax_cross_entropy_with_logits(fc1, y)
     cost = tf.reduce_mean(cost, name='cost')
 
@@ -74,59 +70,37 @@ def get_model(inputs):
     return [prob, correct], cost
 
 def main():
-    dataset_train = BatchData(Mnist('train'), batch_size)
-    dataset_test = BatchData(Mnist('test'), batch_size, remainder=True)
-    callbacks = [
-        SummaryWriter(LOG_DIR),
-        AccuracyValidation(
-            dataset_test,
-            prefix='test', period=1),
-        TrainingAccuracy(),
-        PeriodicSaver(LOG_DIR, period=1)
-    ]
-    optimizer = tf.train.AdamOptimizer(1e-4)
-    sess_config = tf.ConfigProto()
-    sess_config.device_count['GPU'] = 1
-
     with tf.Graph().as_default():
-        G = tf.get_default_graph()
+        dataset_train = BatchData(Mnist('train'), 128)
+        dataset_test = BatchData(Mnist('test'), 128, remainder=True)
+
+        sess_config = tf.ConfigProto()
+        sess_config.device_count['GPU'] = 1
+
+        # prepare model
         image_var = tf.placeholder(tf.float32, shape=(None, IMAGE_SIZE, IMAGE_SIZE), name='input')
         label_var = tf.placeholder(tf.int32, shape=(None,), name='label')
         input_vars = [image_var, label_var]
-
-        for v in input_vars:
-            G.add_to_collection(INPUT_VARS_KEY, v)
         output_vars, cost_var = get_model(input_vars)
-        for v in output_vars:
-            G.add_to_collection(OUTPUT_VARS_KEY, v)
-
-        train_op = optimizer.minimize(cost_var)
-
-        sess = tf.Session(config=sess_config)
-        sess.run(tf.initialize_all_variables())
-
-        with sess.as_default():
-            for ext in callbacks:
-                ext.before_train()
-
-            keep_prob_var = G.get_tensor_by_name(DROPOUT_PROB_VAR_NAME)
-            for epoch in count(1):
-                for dp in dataset_train.get_data():
-                    feed = {keep_prob_var: 0.5}
-                    feed.update(dict(zip(input_vars, dp)))
-
-                    results = sess.run(
-                        [train_op, cost_var] + output_vars, feed_dict=feed)
-                    cost = results[1]
-                    outputs = results[2:]
-                    assert len(outputs) == len(output_vars)
-                    for cb in callbacks:
-                        cb.trigger_step(dp, outputs, cost)
-
-                for cb in callbacks:
-                    cb.trigger_epoch()
-        summary_writer.close()
 
+        config = dict(
+            dataset_train=dataset_train,
+            optimizer=tf.train.AdamOptimizer(1e-4),
+            callbacks=[
+                TrainingAccuracy(),
+                AccuracyValidation(dataset_test,
+                    prefix='test', period=1),
+                PeriodicSaver(LOG_DIR, period=1),
+                SummaryWriter(LOG_DIR),
+            ],
+            session_config=sess_config,
+            inputs=input_vars,
+            outputs=output_vars,
+            cost=cost_var,
+            max_epoch=100,
+        )
+        from train import start_train
+        start_train(config)
 
 
 if __name__ == '__main__':

train.py

+#!/usr/bin/env python2
+# -*- coding: UTF-8 -*-
+# File: train.py
+# Author: Yuxin Wu <ppwwyyxx@gmail.com>
+
+import tensorflow as tf
+from utils import *
+from itertools import count
+
+def start_train(config):
+    """
+    Start training with the given config
+    Args:
+        config: a tensorpack config dictionary
+    """
+    # a Dataflow instance
+    dataset_train = config['dataset_train']
+
+    # a tf.train.Optimizer instance
+    optimizer = config['optimizer']
+
+    # a list of Callback instance
+    callbacks = Callbacks(config.get('callbacks', []))
+
+    # a tf.ConfigProto instance
+    sess_config = config.get('session_config', None)
+
+    # a list of input/output variables
+    input_vars = config['inputs']
+    output_vars = config['outputs']
+    cost_var = config['cost']
+
+    max_epoch = int(config['max_epoch'])
+
+
+    # build graph
+    G = tf.get_default_graph()
+    for v in input_vars:
+        G.add_to_collection(INPUT_VARS_KEY, v)
+    for v in output_vars:
+        G.add_to_collection(OUTPUT_VARS_KEY, v)
+
+    train_op = optimizer.minimize(cost_var)
+
+    sess = tf.Session(config=sess_config)
+    # start training
+    with sess.as_default():
+        sess.run(tf.initialize_all_variables())
+        callbacks.before_train()
+
+        keep_prob_var = G.get_tensor_by_name(DROPOUT_PROB_VAR_NAME)
+        for epoch in xrange(1, max_epoch):
+            for dp in dataset_train.get_data():
+                feed = {keep_prob_var: 0.5}
+                feed.update(dict(zip(input_vars, dp)))
+
+                results = sess.run(
+                    [train_op, cost_var] + output_vars, feed_dict=feed)
+                cost = results[1]
+                outputs = results[2:]
+                callbacks.trigger_step(dp, outputs, cost)
+
+            callbacks.trigger_epoch()

utils/callback.py

@@ -8,6 +8,7 @@ import sys
 import numpy as np
 import os
 from abc import abstractmethod
+
 from .stat import *
 from .utils import *
 from .naming import *
@@ -20,12 +21,12 @@ class Callback(object):
 
     def _before_train(self):
         """
-        Called before training
+        Called before starting iterative training
         """
 
-    # trigger after every step
     def trigger_step(self, dp, outputs, cost):
         """
+        Callback to be triggered after every step (every backpropagation)
         Args:
             dp: the input dict fed into the graph
             outputs: list of output values after running this dp
@@ -33,8 +34,10 @@ class Callback(object):
         """
         pass
 
-    # trigger after every epoch
     def trigger_epoch(self):
+        """
+        Callback to be triggered after every epoch (full iteration of input dataset)
+        """
         pass
 
 class PeriodicCallback(Callback):
@@ -77,11 +80,7 @@ class AccuracyValidation(PeriodicCallback):
         self.dropout_var = self.get_tensor(DROPOUT_PROB_VAR_NAME)
         self.correct_var = self.get_tensor(self.correct_var_name)
         self.cost_var = self.get_tensor(self.cost_var_name)
-        try:
-            self.writer = tf.get_collection(SUMMARY_WRITER_COLLECTION_KEY)[0]
-        except Exception as e:
-            print "SummaryWriter should be the first extension!"
-            raise
+        self.writer = tf.get_collection(SUMMARY_WRITER_COLLECTION_KEY)[0]
 
     def _trigger(self):
         cnt = 0
@@ -121,11 +120,7 @@ class TrainingAccuracy(Callback):
         self.epoch_num = 0
 
     def _before_train(self):
-        try:
-            self.writer = tf.get_collection(SUMMARY_WRITER_COLLECTION_KEY)[0]
-        except Exception as e:
-            print "SummaryWriter should be the first extension!"
-            raise
+        self.writer = tf.get_collection(SUMMARY_WRITER_COLLECTION_KEY)[0]
         output_vars = self.graph.get_collection(OUTPUT_VARS_KEY)
         for idx, var in enumerate(output_vars):
             if var.name == self.correct_var_name:
@@ -194,3 +189,25 @@ class SummaryWriter(Callback):
         self.epoch_num += 1
         self.writer.add_summary(summary_str, self.epoch_num)
 
+class Callbacks(Callback):
+    def __init__(self, callbacks):
+        # put SummaryWriter to the first
+        for idx, cb in enumerate(callbacks):
+            if type(cb) == SummaryWriter:
+                callbacks.insert(0, callbacks.pop(idx))
+                break
+
+        self.callbacks = callbacks
+
+    def before_train(self):
+        for cb in self.callbacks:
+            cb.before_train()
+
+    def trigger_step(self, dp, outputs, cost):
+        for cb in self.callbacks:
+            cb.trigger_step(dp, outputs, cost)
+
+    def trigger_epoch(self):
+        for cb in self.callbacks:
+            cb.trigger_epoch()
+