Week1_2-JuliaBox.ipynb

{
 "cells": [
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/html": [
       "<link href='http://fonts.googleapis.com/css?family=Alegreya+Sans:100,300,400,500,700,800,900,100italic,300italic,400italic,500italic,700italic,800italic,900italic' rel='stylesheet' type='text/css'>\n",
       "<link href='http://fonts.googleapis.com/css?family=Arvo:400,700,400italic' rel='stylesheet' type='text/css'>\n",
       "<link href='http://fonts.googleapis.com/css?family=PT+Mono' rel='stylesheet' type='text/css'>\n",
       "<link href='http://fonts.googleapis.com/css?family=Shadows+Into+Light' rel='stylesheet' type='text/css'>\n",
       "<link href='http://fonts.googleapis.com/css?family=Philosopher:400,700,400italic,700italic' rel='stylesheet' type='text/css'>\n",
       "\n",
       "<style>\n",
       "\n",
       "@font-face {\n",
       "    font-family: \"Computer Modern\";\n",
       "    src: url('http://mirrors.ctan.org/fonts/cm-unicode/fonts/otf/cmunss.otf');\n",
       "}\n",
       "\n",
       "#notebook_panel { /* main background */\n",
       "    background: #ddd;\n",
       "    color: #000000;\n",
       "}\n",
       "\n",
       "\n",
       "\n",
       "/* Formatting for header cells */\n",
       ".text_cell_render h1 {\n",
       "    font-family: 'Philosopher', sans-serif;\n",
       "    font-weight: 400;\n",
       "    font-size: 2.2em;\n",
       "    line-height: 100%;\n",
       "    color: rgb(0, 80, 120);\n",
       "    margin-bottom: 0.1em;\n",
       "    margin-top: 0.1em;\n",
       "    display: block;\n",
       "}\t\n",
       ".text_cell_render h2 {\n",
       "    font-family: 'Philosopher', serif;\n",
       "    font-weight: 400;\n",
       "    font-size: 1.9em;\n",
       "    line-height: 100%;\n",
       "    color: rgb(200,100,0);\n",
       "    margin-bottom: 0.1em;\n",
       "    margin-top: 0.1em;\n",
       "    display: block;\n",
       "}\t\n",
       "\n",
       ".text_cell_render h3 {\n",
       "    font-family: 'Philosopher', serif;\n",
       "    margin-top:12px;\n",
       "    margin-bottom: 3px;\n",
       "    font-style: italic;\n",
       "    color: rgb(94,127,192);\n",
       "}\n",
       "\n",
       ".text_cell_render h4 {\n",
       "    font-family: 'Philosopher', serif;\n",
       "}\n",
       "\n",
       ".text_cell_render h5 {\n",
       "    font-family: 'Alegreya Sans', sans-serif;\n",
       "    font-weight: 300;\n",
       "    font-size: 16pt;\n",
       "    color: grey;\n",
       "    font-style: italic;\n",
       "    margin-bottom: .1em;\n",
       "    margin-top: 0.1em;\n",
       "    display: block;\n",
       "}\n",
       "\n",
       ".text_cell_render h6 {\n",
       "    font-family: 'PT Mono', sans-serif;\n",
       "    font-weight: 300;\n",
       "    font-size: 10pt;\n",
       "    color: grey;\n",
       "    margin-bottom: 1px;\n",
       "    margin-top: 1px;\n",
       "}\n",
       "\n",
       ".CodeMirror{\n",
       "        font-family: \"PT Mono\";\n",
       "        font-size: 100%;\n",
       "}\n",
       "\n",
       "</style>\n",
       "\n"
      ],
      "text/plain": [
       "HTML{ASCIIString}(\"<link href='http://fonts.googleapis.com/css?family=Alegreya+Sans:100,300,400,500,700,800,900,100italic,300italic,400italic,500italic,700italic,800italic,900italic' rel='stylesheet' type='text/css'>\\n<link href='http://fonts.googleapis.com/css?family=Arvo:400,700,400italic' rel='stylesheet' type='text/css'>\\n<link href='http://fonts.googleapis.com/css?family=PT+Mono' rel='stylesheet' type='text/css'>\\n<link href='http://fonts.googleapis.com/css?family=Shadows+Into+Light' rel='stylesheet' type='text/css'>\\n<link href='http://fonts.googleapis.com/css?family=Philosopher:400,700,400italic,700italic' rel='stylesheet' type='text/css'>\\n\\n<style>\\n\\n@font-face {\\n    font-family: \\\"Computer Modern\\\";\\n    src: url('http://mirrors.ctan.org/fonts/cm-unicode/fonts/otf/cmunss.otf');\\n}\\n\\n#notebook_panel { /* main background */\\n    background: #ddd;\\n    color: #000000;\\n}\\n\\n\\n\\n/* Formatting for header cells */\\n.text_cell_render h1 {\\n    font-family: 'Philosopher', sans-serif;\\n    font-weight: 400;\\n    font-size: 2.2em;\\n    line-height: 100%;\\n    color: rgb(0, 80, 120);\\n    margin-bottom: 0.1em;\\n    margin-top: 0.1em;\\n    display: block;\\n}\\t\\n.text_cell_render h2 {\\n    font-family: 'Philosopher', serif;\\n    font-weight: 400;\\n    font-size: 1.9em;\\n    line-height: 100%;\\n    color: rgb(200,100,0);\\n    margin-bottom: 0.1em;\\n    margin-top: 0.1em;\\n    display: block;\\n}\\t\\n\\n.text_cell_render h3 {\\n    font-family: 'Philosopher', serif;\\n    margin-top:12px;\\n    margin-bottom: 3px;\\n    font-style: italic;\\n    color: rgb(94,127,192);\\n}\\n\\n.text_cell_render h4 {\\n    font-family: 'Philosopher', serif;\\n}\\n\\n.text_cell_render h5 {\\n    font-family: 'Alegreya Sans', sans-serif;\\n    font-weight: 300;\\n    font-size: 16pt;\\n    color: grey;\\n    font-style: italic;\\n    margin-bottom: .1em;\\n    margin-top: 0.1em;\\n    display: block;\\n}\\n\\n.text_cell_render h6 {\\n    font-family: 'PT Mono', sans-serif;\\n    font-weight: 300;\\n    font-size: 10pt;\\n    color: grey;\\n    margin-bottom: 1px;\\n    margin-top: 1px;\\n}\\n\\n.CodeMirror{\\n        font-family: \\\"PT Mono\\\";\\n        font-size: 100%;\\n}\\n\\n</style>\\n\\n\")"
      ]
     },
     "execution_count": 4,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "# Setting up a custom stylesheet in IJulia\n",
    "file = open(\"style.css\") # A .css file in the same folder as this notebook file\n",
    "styl = readall(file) # Read the file\n",
    "HTML(\"$styl\") # Output as HTML"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Getting ready---JuliaBox (live programming using a website)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<h2>In this lecture</h2>"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "- [Outcome](#Outcome)\n",
    "- [The JuliaBox website](#The-JuliaBox-website)\n",
    "- [Naming, saving, opening JuliaBox notebooks](#Naming,-saving,-opening-JuliaBox-notebooks)\n",
    "- [A Few More Comments](#A-Few-More-Comments)\n",
    "- [IJulia](#IJulia)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<h2>Outcome</h2>\n",
    "\n",
    "After this lecture, you will be able to\n",
    "- Login to JuliaBox.com\n",
    "- Start a new notebook on JuliaBox.com\n",
    "- Do elementary arithmetic in a JuliaBox.com notebook code cell\n",
    "- Name, save and rename notebooks on JuliaBox.com\n",
    "- Open an existing notebook on JuliaBox.com\n",
    "- (optionally) Install IJulia and run interactive notebooks on your own computer"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "[Back to the top](#In-this-lecture)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<h2>The JuliaBox website</h2>\n",
    "\n",
    "If you don't have a GMail account, please create one now. Then login to www.juliabox.com (via GMail). You should see something like this:\n",
    "\n",
    "<img src=\"Week1_Lecture2_1-JuliaBox.png\" alt=\"(Screenshot of first JuliaBox page)\">\n",
    "\n",
    "\n",
    "\n",
    "\n",
    "Click on the New button (near the top right), selecting Julia 0.4.6 as your kernel. It opens a new tab in your browser, using the name Untitled. It should look like this:\n",
    "\n",
    "<img src=\"Week1_Lecture2_2-Notebook.png\" alt=\"(Screenshot of empty JuliaBox notebook)\">\n",
    "\n",
    "\n",
    "What you see is an empty notebook, with a cell ready to receive input. Note that it is a code cell, indicated by a message in the toolbar at the top of your browser page, and also by the \"In [ ]:\" to the left of the cell.\n",
    "\n",
    "You will need to ensure that cells with code in them are always code cells. Otherwise they will not do any programming tasks for you.\n",
    "\n",
    "Let's try it out! We'll enter some very elementary arithmetic expressions, and get the notebook to evaluate them by pressing Shift-Enter\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "2"
      ]
     },
     "execution_count": 5,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "1+1"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "-31"
      ]
     },
     "execution_count": 6,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "2003 * 2016\n",
    "45 - 76\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Note that the elementary arithmetic operators are  +  -   *   \\   ^ \n",
    "\n",
    "Parentheses should be used when there is any possibility of more than one interpretation."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "[Back to the top](#In-this-lecture)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<h2>Naming, saving, opening JuliaBox notebooks</h2>\n",
    "\n",
    "One often wants to save a notebook for future use. JuliaBox gives it the unhelpful name \"Untitled\", so the first step is to rename your current notebook.\n",
    "\n",
    "To do so, click on File (near the top left), a menu opens, click Rename... and type the name of your choice in the box that opens. Click OK or just hit Enter.\n",
    "\n",
    "Every once in a while you should save the notebook you are currently working on, and also just before closing the notebook and leaving. \n",
    "\n",
    "To save, click on File and in the menu click the Save and Checkpoint option.\n",
    "\n",
    "One should always leave gracefully, if you can. So when done with a notebook, click on File, click on Save and Checkpoint, and then click the Close and Halt option.\n",
    "\n",
    "At any time you wish to, you can open the notebook again. Just go the directory page, which is the very first one that JuliaBox opened for you. It will be there under you name you saved it as. Just click on it, and it opens in its own tab."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "[Back to the top](#In-this-lecture)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<h2>A Few More Comments</h2>\n",
    "\n",
    "### Julia is an interpreted language\n",
    "\n",
    "What you have just seen is a demonstration of how interpreted languages work: the moment they get a complete line of code, they execute it. Python and Matlab are also interpreted languages.\n",
    "\n",
    "This is the opposite of compiled languages like C and Fortran. There, the code has to be compiled before it is run."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Julia as a command line interpreter\n",
    "\n",
    "Actually, the situation here in a notebook is a bit of a luxury: one can put several lines in cell and execute them all at once. From the command line, really one can only execute one line at a time****. In this, it is quite similar to Python and Matlab.\n",
    "\n",
    "****Terms and conditions apply: a single command line entry can look as if it contains several lines. And one can chain several (usually very short) commands on one line."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Code files in Julia\n",
    "\n",
    "Although JuliaBox (equivalently IJulia) is a wonderful environment in which to explore the pleasures of coding in Julia, you should know that many Julia projects consists purely of files that contain lines of Julia code.\n",
    "\n",
    "This of course is how most computer programs are organised.\n",
    "\n",
    "In particular, Julia itself consists of a very basic core, written in C, the Base package, mostly written in Julia, and many extensions, some of them written in other languages but mostly written in Julia. This adds up to many thousands of lines of code, organised in hundreds of files.\n",
    "\n",
    "In this course, we will not require you to write files of Julia code."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### The Base package\n",
    "\n",
    "When you start a new notebook on JuliaBox, you have available to you the Base package. But often one wants to do things that are available only in extensions. They then have to be added to your JuliaBox session. We will cover that in Lesson 3, and use several of the extension packages in Lesson 3 and in Lesson 4."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "[Back to the top](#In-this-lecture)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<h2>IJulia</h2>\n",
    "\n",
    "\n",
    "For those of you who have installed Julia on your own local computer, here's how to get interactive notebooks running\n",
    "\n",
    "Step 1: Start Julia, and go to the command line.\n",
    "\n",
    "Step 2: Install IJulia by typing and entering \"Pkg.add(\"IJulia\")\".\n",
    "\n",
    "Step 3: Activate IJulia by typing and entering \"using IJulia\".\n",
    "\n",
    "Step 4: Start up IJulia by typing and entering \"notebook()\". It opens in a browser (if necessary, starting up the browser).\n",
    "\n",
    "It can be a little unclear how to shut it down. I generally first close the browser window, then return to the Julia terminal and press Ctrl-C. The other way round also works. "
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "[Back to the top](#In-this-lecture)"
   ]
  }
 ],
 "metadata": {
  "kernelspec": {
   "display_name": "Julia 0.4.7",
   "language": "julia",
   "name": "julia-0.4"
  },
  "language_info": {
   "file_extension": ".jl",
   "mimetype": "application/julia",
   "name": "julia",
   "version": "0.4.7"
  }
 },
 "nbformat": 4,
 "nbformat_minor": 0
}