Lecture-1.ipynb

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   "source": [
    "## Lecture 1 - Placeholders, Constants, Operations and Variables in TF ##\n"
   ]
  },
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      "/Users/cihan/anaconda3/lib/python3.6/site-packages/h5py/__init__.py:36: FutureWarning: Conversion of the second argument of issubdtype from `float` to `np.floating` is deprecated. In future, it will be treated as `np.float64 == np.dtype(float).type`.\n",
      "  from ._conv import register_converters as _register_converters\n"
     ]
    }
   ],
   "source": [
    "import tensorflow as tf"
   ]
  },
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   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### This is a variable in Tensorflow:###"
   ]
  },
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   "source": [
    "variable1 = tf.Variable(2)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### This is a Constant in Tensorflow:###"
   ]
  },
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   "cell_type": "code",
   "execution_count": 3,
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   "source": [
    "constant1 = tf.constant(3)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### This is a placeholder in Tensorflow: ###\n",
    "They are used for feeding data from out of the model. (Will be explained)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [],
   "source": [
    "placeholder1 = tf.placeholder(dtype=tf.int32)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### You can use math operations for variables and constants:###"
   ]
  },
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    "multiplyValue = placeholder1 * variable1"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### This is an addition operation in Tensorflow: ###"
   ]
  },
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   "cell_type": "code",
   "execution_count": 15,
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   "source": [
    "addValue = tf.add(multiplyValue, constant1)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Initialize variables before running ###\n",
    "If you have variables in TF, you need to initialize it. A standart code.\n",
    "If you use only placehoders and constants, No need to init."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 16,
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   "source": [
    "init_op = tf.global_variables_initializer()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Sessions: ###\n",
    "In Tensorflow, Program runs different than normal python. At the top part, we created some operations.\n",
    "Everthing is a operation in Tensorflow. When we start a session, It will execute the operations."
   ]
  },
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   "cell_type": "code",
   "execution_count": 22,
   "metadata": {},
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    {
     "name": "stdout",
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     "text": [
      "11\n"
     ]
    }
   ],
   "source": [
    "with tf.Session() as session:\n",
    "    # First we have to run the init operation because we have variables.\n",
    "    session.run(init_op)\n",
    "    # This functions runs everything.\n",
    "    # feed_dict is a dictionary that you give values to placeholders.\n",
    "    result = session.run(addValue, feed_dict={placeholder1: 4})\n",
    "    print(result)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Have a good day..."
   ]
  }
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