1 .. Objectives

     2 .. ----------

     3 

     4 .. A - Students and teachers from Science and engineering backgrounds

     5    B - 

     6    C - 

     7    D - 

     8 

     9 .. Prerequisites

    10 .. -------------

    11 

    12 ..   1. Getting started with lists

    13      

    14 .. Author              : Nishanth Amuluru

    15    Internal Reviewer   : 

    16    External Reviewer   :

    17    Checklist OK?       : <put date stamp here, if OK> [2010-10-05]

    18 

    19 Script

    20 ------

    21 

    22 Hello friends and welcome to the tutorial on "Using SAGE to teach"

    23 

    24 {{{ Show the slide containing title }}}

    25 

    26 {{{ Show the slide containing the outline slide }}}

    27 

    28 In this tutorial, we shall learn

    29 

    30  * How to use the "@interact" feature of SAGE for better demonstration

    31  * How to use SAGE for collaborative learning

    32 

    33 Let us look at a typical example of demonstrating a damped oscillation.

    34 ::

    35 

    36     t = var('t')

    37     p1 = plot( e^(-t) * sin(2*t), (t, 0, 15))

    38     show(p1)

    39 

    40 Now let us reduce the damping factor

    41 ::

    42 

    43     t = var('t')

    44     p1 = plot( e^(-t/2) * sin(2*t), (t, 0, 15))

    45     show(p1)

    46 

    47 Now if we want to reduce the damping factor even more, we would be using

    48 e^(-t/3). We can observe that every time we have to change, all we do is change

    49 something very small and re evaluate the cell.

    50 

    51 This process can be automated using the ``@interact`` feature of SAGE.

    52 

    53 ::

    54 

    55     @interact

    56     def plot_damped(n=1):

    57         t = var('t')

    58         p1 = plot( e^(-t/n) * sin(2*t), (t, 0, 20))

    59         show(p1)

    60 

    61 We can see that the function is evaluated and the plot is shown. We can also

    62 see that there is a field to enter the value of ``n`` and it is currently set

    63 to ``1``. Let us change it to 2 and hit enter.

    64 

    65 We see that the new plot with reduced damping factor is shown. Similarly we can

    66 change ``n`` to any desired value and hit enter and the function will be

    67 evaluated. 

    68 

    69 This is a very handy tool while demonstrating or teaching.

    70 

    71 {{{ Pause here and try out the following exercises }}}

    72 

    73 %% 1 %% Plot the sine curve and vary its frequency using the ``@interact``

    74 

    75 {{{ continue from paused state }}}

    76 

    77 ::

    78 

    79     @interact

    80     def sine_plot(n=1):

    81         x = var('x')

    82         p2 = plot(sin(n*x), (x, 0, 2*pi))

    83         show(p2)

    84 

    85 Often we would want to vary a parameter over range instead of taking it as an

    86 input from the user. For instance we do not want the user to give ``n`` as 0

    87 for the damping oscillation we discussed. In such cases we use a range of

    88 values as the default argument.

    89 ::

    90 

    91     @interact

    92     def plot_damped(n=(1..10)):

    93         t = var('t')

    94         p1 = plot( e^(-t/n) * sin(2*t), (t, 0, 20))

    95         show(p1)

    96 

    97 We get similar plot but the only difference is the input widget. Here it is a

    98 slider unlike an input field. We can see that as the slider is moved, the

    99 function is evaluated and plotted accordingly.

   100 

   101 {{{ Pause here and try out the following exercises }}}

   102 

   103 %% 2 %% Take a string as input from user and circular shift it to the left and

   104         vary the shift length using a slider

   105 

   106 {{{ continue from paused state }}}

   107 

   108 ::

   109 

   110     @interact

   111     def str_shift(s="MADAM", shift=(0..8)):

   112         shift_len = shift % len(s)

   113         chars = list(s)

   114         shifted_chars = chars[shift_len:] + chars[:shift_len]

   115         print "Actual String:", s

   116         print "Shifted String:", "".join(shifted_chars)

   117 

   118 Sometimes we want the user to have only a given set of options. We use a list

   119 of items as the default argument in such situations.

   120 ::

   121 

   122     @interact

   123     def str_shift(s="STRING", shift=(0..8), direction=["Left", "Right"]):

   124         shift_len = shift % len(s)

   125         chars = list(s)

   126         if direction == "Right":

   127             shifted_chars = chars[-shift_len:] + chars[:-shift_len]

   128         else:

   129             shifted_chars = chars[shift_len:] + chars[:shift_len]

   130         print "Actual String:", s

   131         print "Shifted String:", "".join(shifted_chars)

   132 

   133 We can see that buttons are displayed which enables us to select from a given

   134 set of options.

   135 

   136 We have learnt how to use the ``@interact`` feature of SAGE for better

   137 demonstration. We shall look at how to use SAGE worksheets for collaborative

   138 learning.

   139 

   140 The first feature we shall see is the ``publish`` feature. Open a worksheet and

   141 in the top right, we can see a button called ``publish``. Click on that and we

   142 get a confirmation page with an option for re publishing.

   143 

   144 For now lets forget that opion and simply publish by cliking ``yes``. The

   145 worksheet is now published. 

   146 

   147 Now lets signout and go to the sage notebook home. We see link to browse

   148 published worksheets. Lets click on it and we can see the worksheet. This does

   149 not require login and anyone can view the worksheet.

   150 

   151 Alternatively, if one wants to edit the sheet, there is a link on top left

   152 corner that enables the user to download a copy of the sheet onto their home.

   153 This way they can edit a copy of the worksheet.

   154 

   155 We have learnt how to publish the worksheets to enable users to edit a copy.

   156 Next, we shall look at how to enable users to edit the actual worksheet itself.

   157 

   158 Let us open the worksheet and we see a link called ``share`` on the top right

   159 corner of the worksheet. Click the link and we get a box where we can type the

   160 usernames of users whom we want to share the worksheet with. We can even

   161 specify multiple users by seperating their names using commas. Once we have

   162 shared the worksheet, the worksheet appears on the home of shared users.

   163 

   164 {{{ Show summary slide }}}

   165 

   166 This brings us to the end of the tutorial.

   167 we have learnt

   168 

   169  * How to user interactive feaures of SAGE

   170  * How to publish our work

   171  * How to edit a copy of one of the published worksheets

   172  * How to share the worksheets with fellow users

   173 

   174 {{{ Show the "sponsored by FOSSEE" slide }}}

   175 

   176 #[Nishanth]: Will add this line after all of us fix on one.

   177 This tutorial was created as a part of FOSSEE project, NME ICT, MHRD India

   178 

   179 Hope you have enjoyed and found it useful.

   180 Thankyou

   181