add examples from tensorflow book.

Deep_Learning_with_TensorFlow/0.12.0/Chapter03/1. 图，张量及会话.ipynb

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+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#### 1. 定义两个不同的图"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "[ 0.]\n",
+      "[ 1.]\n"
+     ]
+    }
+   ],
+   "source": [
+    "import tensorflow as tf\n",
+    "\n",
+    "g1 = tf.Graph()\n",
+    "with g1.as_default():\n",
+    "    v = tf.get_variable(\"v\", [1], initializer = tf.zeros_initializer) # 设置初始值为0\n",
+    "\n",
+    "g2 = tf.Graph()\n",
+    "with g2.as_default():\n",
+    "    v = tf.get_variable(\"v\", [1], initializer = tf.ones_initializer())  # 设置初始值为1\n",
+    "    \n",
+    "with tf.Session(graph = g1) as sess:\n",
+    "    tf.global_variables_initializer().run()\n",
+    "    with tf.variable_scope(\"\", reuse=True):\n",
+    "        print(sess.run(tf.get_variable(\"v\")))\n",
+    "\n",
+    "with tf.Session(graph = g2) as sess:\n",
+    "    tf.global_variables_initializer().run()\n",
+    "    with tf.variable_scope(\"\", reuse=True):\n",
+    "        print(sess.run(tf.get_variable(\"v\")))"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "collapsed": true
+   },
+   "source": [
+    "#### 2. 张量的概念"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Tensor(\"add:0\", shape=(2,), dtype=float32)\n",
+      "[ 3.  5.]\n"
+     ]
+    }
+   ],
+   "source": [
+    "import tensorflow as tf\n",
+    "a = tf.constant([1.0, 2.0], name=\"a\")\n",
+    "b = tf.constant([2.0, 3.0], name=\"b\")\n",
+    "result = a + b\n",
+    "print result\n",
+    "\n",
+    "sess = tf.InteractiveSession ()\n",
+    "print(result.eval())\n",
+    "sess.close()"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#### 3. 会话的使用"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "3.1 创建和关闭会话"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "[ 3.  5.]\n"
+     ]
+    }
+   ],
+   "source": [
+    "# 创建一个会话。\n",
+    "sess = tf.Session()\n",
+    "\n",
+    "# 使用会话得到之前计算的结果。\n",
+    "print(sess.run(result))\n",
+    "\n",
+    "# 关闭会话使得本次运行中使用到的资源可以被释放。\n",
+    "sess.close()"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "3.2 使用with statement 来创建会话"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 4,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "[ 3.  5.]\n"
+     ]
+    }
+   ],
+   "source": [
+    "with tf.Session() as sess:\n",
+    "    print(sess.run(result))"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "3.3 指定默认会话"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 5,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "[ 3.  5.]\n"
+     ]
+    }
+   ],
+   "source": [
+    "sess = tf.Session()\n",
+    "with sess.as_default():\n",
+    "     print(result.eval())"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 6,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "[ 3.  5.]\n",
+      "[ 3.  5.]\n"
+     ]
+    }
+   ],
+   "source": [
+    "sess = tf.Session()\n",
+    "\n",
+    "# 下面的两个命令有相同的功能。\n",
+    "print(sess.run(result))\n",
+    "print(result.eval(session=sess))"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#### 4. 使用tf.InteractiveSession构建会话"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 7,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "[ 3.  5.]\n"
+     ]
+    }
+   ],
+   "source": [
+    "sess = tf.InteractiveSession ()\n",
+    "print(result.eval())\n",
+    "sess.close()"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#### 5. 通过ConfigProto配置会话"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 8,
+   "metadata": {
+    "collapsed": true
+   },
+   "outputs": [],
+   "source": [
+    "config=tf.ConfigProto(allow_soft_placement=True, log_device_placement=True)\n",
+    "sess1 = tf.InteractiveSession(config=config)\n",
+    "sess2 = tf.Session(config=config)"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.10"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 1
+}