51 to use Sage and nothing else!

    51 to use Sage and nothing else! The Sage notebook also provides a

    52 convenient way of sharing and publishing our work which is very handy

    53 when we use Sage for research or for teaching.

    59 on the Sage prompt. This will start the Sage Notebook server.

    61 on the Sage prompt. This will start the Sage Notebook server. If we

    60 If we are starting the notebook server for the first time, we are

    62 are starting the notebook server for the first time, we are prompted

    61 prompted to enter the password for the admin. Type the password and

    63 to enter the password for the admin. Type the password and make a note

    62 make a note of it. After this Sage automatically starts a browser page

    64 of it. After this Sage automatically starts a browser page for you

    63 for you with the notebook opened.

    65 with the notebook opened.

    92 of this page we have the links to various pages. The home link takes

    94 of this page we have the links to various pages. 

    93 to the admin home page. The published link takes us the page which

    95 

    94 lists all the published worksheets.

    96 {{{ Whenever you talk on an individual link point your mouse towards

    95 

    97 the link. For each of the link go to the page and explain as below }}}

    96 

    98 

    97 

    99 The home link takes us to the admin home page. The published link

    98 

   100 takes us to the page which lists all the published worksheets. The log

    99 This brings us to the end of the session on using Sage notebook. In

   101 link has the complete log of all the actions we did on the

   100 this tutorial session we learnt

   102 notebook. We have the settings link where can configure our notebook,

   101 

   103 the notebook server, we can create and mangage accounts. We have a

   102   *

   104 link to help upon clicking opens a new window with the complete help

   105 of Sage. The entire documentation of Sage is supplied with Sage for

   106 offline reference and this help link is the way to get into it. Then

   107 we can report bugs about Sage by clicking on Report a Problem link and

   108 there is a link to sign out of the notebook.

   109 

   110 We can create a new worksheet by clicking New Worksheet link

   111 

   112 {{{ Click on the link }}}

   113 

   114 Sage prompts you for a name for the worksheet. Let us name the

   115 worksheet as nbtutorial. Now we have our first worksheet which is

   116 empty.

   117 

   118 A worksheet will contain a collection of cells. Every Sage command

   119 must be entered in this cell. Cell is equivalent to the prompt on

   120 console. When we create a new worksheet, to start with we will have

   121 one empty cell. Let us try out some math here::

   122 

   123   2 + 2

   124   57.1 ^ 100

   125 

   126 The cap operator is used for exponentiation. If you observed carefully

   127 we typed two commands but the output of only last command was

   128 displayed. By default each cell displays the result of only the last

   129 operation. We have to use print statement to display all the results

   130 we want to be displayed.

   131 

   132 {{{ Demonstrate creating a new cell }}}

   133 

   134 Now to perform more operations we want more cells. So how do we create

   135 a new cell? It is very simple. As we hover our mouse above or below

   136 the existing cells we see a blue line, by clicking on this new line we

   137 can create a new cell. 

   138 

   139 We have a cell, we have typed some commands in it, but how do we

   140 evaluate that cell? Pressing Shift along with Enter evaluates the

   141 cell. Alternatively we can also click on the evaluate link to evaluate

   142 the cell

   143 

   144 {{{ Evaluate the cell and demonstrate for both methods separately

   145 }}}::

   146 

   147   matrix([[1,2], [3,4]])^(-1)

   148 

   149 After we create many cells, we may want to move between the cells. To

   150 move between the cells use Up and Down arrow keys. Also clicking on

   151 the cell will let you edit that particular cell.

   152 

   153 {{{ Move between two cells created }}}

   154 

   155 To delete a cell, clear the contents of the cell and hit backspace

   156 

   157 {{{ Clear and demonstrate deleting the cell }}}::

   158 

   159   Makes no sense

   160 

   161 If you want to add annotations in the worksheet itself on the blue

   162 line that appears on hovering the mouse around the cell, Hold Shift

   163 and click on the line. This creates a What You See Is What You Get

   164 cell.

   165 

   166 {{{ Create a HTML editable cell }}}

   167 

   168 We can make our text here rich text. We can make it bold, Italics, we

   169 can create bulleted and enumerated lists in this area::

   170 

   171   This text contains both the **bold** text and also *italicised*

   172   text.

   173   It also contains bulleted list:

   174   * Item 1

   175   * Item 2

   176   It also contains enumerate list:

   177   1. Item 1

   178   2. Item 2

   179 

   180 In the same cell we can display typeset math using the LaTeX like

   181 syntax::

   182 

   183   $\int_0^\infty e^{-x} \, dx$

   184 

   185 We enclose the math to be typeset within $ and $ or $$ and $$ as in

   186 LaTeX.

   187 

   188 We can also obtain help for a particular Sage command or function

   189 within the worksheet itself by using a question mark following the

   190 command::

   191 

   192   sin?

   193 

   194 Evaluating this cell gives me the entire help for the sin function

   195 inline on the worksheet itself. Similarly we can also look at the

   196 source code of each command or function using double question mark::

   197 

   198   matrix??

   199 

   200 Sage notebook also provides the feature for autocompletion. To

   201 autocomplete a command type first few unique characters and hit tab

   202 key::

   203 

   204   sudo<tab>

   205 

   206 To see all the commands starting with a specific name type those

   207 characters and hit tab::

   208 

   209   plo<tab>

   210 

   211 To list all the methods that are available for a certain variable or

   212 a datatype we can use the variable name followed by the dot to access

   213 the methods available on it and then hit tab::

   214 

   215   s = 'Hello'

   216   s.rep<tab>

   217 

   218 The output produced by each cell can be one of the three states. It

   219 can be either the full output, or truncated output or hidden output.

   220 The output area will display the error if the Sage code we wrote in

   221 the cell did not successfully execute::

   222 

   223   a, b = 10

   224 

   225 {{{ Show the three states }}}

   226 

   227 The default output we obtained now is a truncated output. Clicking at

   228 the left of the output area when the mouse pointer turns to hand gives

   229 us the full output, clicking again makes the output hidden and it

   230 cycles.

   231 

   232 Lastly, Sage supports a variety of languages and each cell on the

   233 worksheet can contain code written in a specific language. It is

   234 possible to instruct Sage to interpret the code in the language we

   235 have written. This can be done by putting percentage sign(%) followed

   236 by the name of the language. For example, to interpret the cell as

   237 Python code we put::

   238 

   239   %python

   240 

   241 as the first line in the cell. Similarly we have: %sh for shell

   242 scripting, %fortran for Fortran, %gap for GAP and so on. Let us see

   243 how this works. Say I have an integer. The type of the integer in

   244 default Sage mode is

   245 {{{ Read the output }}}::

   246 

   247   a = 1

   248   type(a)

   249 

   250   Output: <type 'sage.rings.integer.Integer'>

   251 

   252 We see that Integers are Sage Integers. Now let us put %python as the

   253 first line of the cell and execute the same code snippet::

   254 

   255   %python

   256   a = 1

   257   type(a)

   258 

   259   Output: <type 'int'>

   260 

   261 Now we see that the integer is a Python integer. Why? Because now we

   262 instructed Sage to interpret that cell as Python code.

   263 

   264 This brings us to the end of the tutorial on using Sage. We learnt

   265 quite a lot about using the Notebook User Interface of Sage. We are

   266 now confident that we can comfortably use the notebook to learn more

   267 about Sage in the following tutorials. Let us summarize what we

   268 learnt. In this session we learnt

   269 

   270   * What is Sage

   271   * How to start Sage shell

   272   * What is Sage notebook

   273   * How to start the Sage notebook

   274   * How to create accounts and start using the notebook

   275   * How to create new worksheets

   276   * The menus available on the notebook

   277   * About cells in the worksheet

   278   * Methods to evaluate the cell, create new cells, delete the cells

   279     and navigate around the cells

   280   * To make annotations in the worksheet

   281   * Tab completions

   282   * And embedding code of other scripting languages in the cells