2 % Tutorial slides on Python.

     2 %Tutorial slides on Python.

     4 % Author: Prabhu Ramachandran <prabhu at aero.iitb.ac.in>

     4 % Author: FOSSEE 

     5 % Copyright (c) 2005-2009, Prabhu Ramachandran

     5 % Copyright (c) 2009, FOSSEE, IIT Bombay

     8 \documentclass[compress,14pt]{beamer}

     8 \documentclass[14pt,compress]{beamer}

     9 % \documentclass[handout]{beamer}

     9 %\documentclass[draft]{beamer}

    10 % \usepackage{pgfpages}

    10 %\documentclass[compress,handout]{beamer}

    11 % \pgfpagesuselayout{4 on 1}[a4paper,border, shrink=5mm,landscape]

    11 %\usepackage{pgfpages} 

    12 \usepackage{tikz}

    12 %\pgfpagesuselayout{2 on 1}[a4paper,border shrink=5mm]

    13 \newcommand{\hyperlinkmovie}{}

    13 

    14 %\usepackage{movie15}

    14 % Modified from: generic-ornate-15min-45min.de.tex

    15 

    16 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

    17 % Note that in presentation mode 

    18 % \paperwidth  364.19536pt

    19 % \paperheight 273.14662pt

    20 % h/w = 0.888

    21 

    22 

    38 \usepackage{times}

    24 %\usepackage{times}

    58 % My Macros

    43 % Macros

    59 \setbeamercolor{postit}{bg=yellow,fg=black}

    80 \newcommand{\inctime}[1]{\addtocounter{time}{#1}{\vspace*{0.1in}\tiny \thetime\ m}}

    52 \newcommand{\inctime}[1]{\addtocounter{time}{#1}{\tiny \thetime\ m}}

    81 

    53 

    82 \newcommand\BackgroundPicture[1]{%

    54 \newcommand{\typ}[1]{\lstinline{#1}}

    83   \setbeamertemplate{background}{%

    55 

    84       \parbox[c][\paperheight]{\paperwidth}{%

    56 \newcommand{\kwrd}[1]{ \texttt{\textbf{\color{blue}{#1}}}  }

    85       \vfill \hfill

    57 

    86  \hfill \vfill

    58 %%% This is from Fernando's setup.

    87 }}}

    59 % \usepackage{color}

    88 

    60 % \definecolor{orange}{cmyk}{0,0.4,0.8,0.2}

    89 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

    61 % % Use and configure listings package for nicely formatted code

    90 % Configuring the theme

    62 % \usepackage{listings}

    91 %\setbeamercolor{normal text}{fg=white}

    63 % \lstset{

    92 %\setbeamercolor{background canvas}{bg=black}

    64 %    language=Python,

    93 

    65 %    basicstyle=\small\ttfamily,

    66 %    commentstyle=\ttfamily\color{blue},

    67 %    stringstyle=\ttfamily\color{orange},

    68 %    showstringspaces=false,

    69 %    breaklines=true,

    70 %    postbreak = \space\dots

    71 % }

    98 \title[3D Plotting]{3D data Visualization}

    76 \title[Basic Python]{Python language: Functions, modules and objects}

    99 

    77 

   100 \author[FOSSEE] {FOSSEE}

    78 \author[FOSSEE Team] {The FOSSEE Group}

   103 \date[] {8 November, 2009\\Day 2, Session 5}

    81 \date[] {8 November, 2009\\Day 2, Session 3}

   104 

   107 %\pgfdeclareimage[height=0.75cm]{iitblogo}{iitblogo}

    84 %\pgfdeclareimage[height=0.75cm]{iitmlogo}{iitmlogo}

   108 %\logo{\pgfuseimage{iitblogo}}

    85 %\logo{\pgfuseimage{iitmlogo}}

   109 

    86 

   110 \AtBeginSection[]

   111 {

   112   \begin{frame}<beamer>

   113     \frametitle{Outline}      

   114     \tableofcontents[currentsection,currentsubsection]

   115   \end{frame}

   116 }

   140   \maketitle

   117   \titlepage

   149 \section{3D Data Visualization}

   126 \section{Functions}

   150 

   127 \subsection{Default arguments}

   128 \begin{frame}[fragile]

   129   \frametitle{Functions: default arguments}

   130   \begin{lstlisting}

   131 In []: greet = 'hello world'

   132 

   133 In []: greet.split()

   134 Out[]: ['hello', 'world']

   135 

   136 In []: line = 'Rossum, Guido, 54, 46, 55'

   137 

   138 In []: line.split(',')

   139 Out[]: ['Rossum', ' Guido', ' 54',

   140                         ' 46', ' 55']

   141   \end{lstlisting}

   142 \end{frame}

   143 

   144 \begin{frame}[fragile]

   145   \frametitle{Functions: default arguments \ldots}

   146   \begin{lstlisting}

   147 In []: def welcome(greet, name="World"):

   148   ....     print greet, name

   149 

   150 In []: welcome("Hello")

   151 Hello World

   152 

   153 In []: welcome("Hi", "Guido")

   154 Hi Guido

   155   \end{lstlisting}

   156 \end{frame} 

   157 

   158 \subsection{Keyword arguments}

   159 \begin{frame}[fragile]

   160   \frametitle{Functions: Keyword arguments}

   161 We have seen the following

   162 \begin{lstlisting}

   163 In []: legend(['sin(2y)'], 

   164                  loc = 'center')

   165 

   166 In []: plot(y, sin(y), 'g',

   167                  linewidth = 2)

   168 

   169 In []: annotate('local max',

   170                  xy = (1.5, 1))

   171 

   172 In []: pie(science.values(),

   173             labels = science.keys())

   174   \end{lstlisting}

   175 \end{frame}

   176 

   177 \begin{frame}[fragile]

   178   \frametitle{Functions: keyword arguments \ldots}

   179   \begin{lstlisting}

   180 In []: def welcome(greet, name="World"):

   181   ....     print greet, name

   182 

   183 In []: welcome("Hello", "James")

   184 Hello James

   185 

   186 In []: welcome("Hi", name="Guido")

   187 Hi Guido

   188 

   189 In []: welcome(name="Guido", greet="Hey")

   190 Hey Guido

   191   \end{lstlisting}

   192 \end{frame}

   193 

   194 \subsection{Built-in functions}

   152     \frametitle{What is visualization?}

   196   {Before writing a function}

   153     \Large

   197   \begin{itemize}

   154     \begin{center}

   198       \item Variety of built-in functions are available

   155     Visual representation of data

   199       \item \typ{abs, any, all, len, max, min}

   156     \end{center}

   200       \item \typ{pow, range, sum, type}

   157 \end{frame}

   201       \item Refer here:

   158 

   202           \url{http://docs.python.org/library/functions.html}

   159 

   203   \end{itemize}

   160 %% \begin{frame}

   204   \inctime{10} 

   161 %%     \frametitle{Is this new?}    

   205 \end{frame}

   162 %%     \begin{center}

   206 

   163 %%     We have moved from:

   207 \subsection{Exercises}

   164 %%     \end{center}

   208 \begin{frame}{Problem set 3: Problem 3.1}

   165 %%     \begin{columns}

   209   Write a function to return the gcd of two numbers.

   166 %%     \column{}

   210 \end{frame}

   167 %%     \hspace*{-1in}    

   211 

   168 %%     \includegraphics[width=1.75in,height=1.75in, interpolate=true]{data/3832}      

   212 \begin{frame}{Problem 3.2}

   169 %%     \column{}\hspace*{-0.25in}

   213 Write a program to print all primitive pythagorean triads (a, b, c) where a, b are in the range 1---100 \\

   170 %%     To

   214 A pythagorean triad $(a,b,c)$ has the property $a^2 + b^2 = c^2$.\\By primitive we mean triads that do not `depend' on others. For example, (4,3,5) is a variant of (3,4,5) and hence is not primitive. And (10,24,26) is easily derived from (5,12,13) and is also not primitive.

   171 %%     \column{}

   215 \end{frame}

   172 %%     \hspace*{-1in}

   216 

   173 %%     \includegraphics[width=1.75in, height=1.75in, interpolate=true]{data/torus}  

   217 \begin{frame}{Problem 3.3}

   174 %%     \end{columns}

   218   Write a program that generates a list of all four digit numbers that have all their digits even and are perfect squares.\newline\\\emph{For example, the output should include 6400 but not 8100 (one digit is odd) or 4248 (not a perfect square).}

   175 %% \end{frame}

   219 

   220 \inctime{15}

   221 \end{frame}

   222 

   223 \section{Modules}

   224 \begin{frame}[fragile]

   225   \frametitle{\texttt{from} \ldots \texttt{import} magic}

   226   \begin{lstlisting}

   227 from scipy.integrate import odeint

   228 

   229 from scipy.optimize import fsolve

   230   \end{lstlisting}

   231 \emphbar{Above statements import a function to our namespace}

   232 \end{frame}

   233 

   234 \begin{frame}[fragile]

   235   \frametitle{Running scripts from command line}

   236   \small

   237   \begin{itemize}

   238     \item Fire up a terminal

   239     \item python four\_plot.py

   240   \end{itemize}

   241   \pause

   242   \begin{lstlisting}

   243 Traceback (most recent call last):

   244   File "four_plot.py", line 1, in <module>

   245     x = linspace(-5*pi, 5*pi, 500)

   246 NameError: name 'linspace' is not defined

   247   \end{lstlisting}

   248 \end{frame}

   249 

   250 \begin{frame}[fragile]

   251   \frametitle{Remedy}

   252   \begin{lstlisting}

   253 from scipy import *

   254   \end{lstlisting}

   255 \alert{Now run python four\_plot.py again!}

   256   \pause

   257   \begin{lstlisting}

   258 Traceback (most recent call last):

   259   File "four_plot.py", line 4, in <module>

   260     plot(x, x, 'b')

   261 NameError: name 'plot' is not defined

   262   \end{lstlisting}

   263 \end{frame}

   264 

   265 \begin{frame}[fragile]

   266   \frametitle{Remedy \ldots}

   267   \begin{lstlisting}

   268 from pylab import *

   269   \end{lstlisting}

   270 \alert{Now run python four\_plot.py again!!}

   271 \end{frame}

   272 

   273 \begin{frame}[fragile]

   274   \frametitle{Modules}

   275   \begin{itemize}

   276     \item The \kwrd{import} keyword ``loads'' a module

   277     \item One can also use:

   278       \begin{lstlisting}

   279 In []: from scipy import *

   280 In []: from scipy import linspace

   281       \end{lstlisting}    

   282     \item What is the difference?

   283     \item \alert{Use the former only in interactive mode}

   284     \end{itemize}

   285 \end{frame}

   286 

   287 \begin{frame}[fragile]

   288   \frametitle{Package hierarchies}

   289   \begin{lstlisting}

   290 from scipy.integrate import odeint

   291 

   292 from scipy.optimize import fsolve

   293   \end{lstlisting}

   294 \end{frame}

   295 

   296 \begin{frame}[fragile]

   297   \frametitle{\texttt{from} \ldots \texttt{import} - conventional way!}

   298   \small

   299   \begin{lstlisting}

   300 from scipy import linspace, pi, sin

   301 from pylab import plot, legend, annotate

   302 from pylab import xlim, ylim

   303 

   304 x = linspace(-5*pi, 5*pi, 500)

   305 plot(x, x, 'b')

   306 plot(x, -x, 'b')

   307 plot(x, sin(x), 'g', linewidth=2)

   308 plot(x, x*sin(x), 'r', linewidth=3)

   309 legend(['x', '-x', 'sin(x)', 'xsin(x)'])

   310 annotate('origin', xy = (0, 0))

   311 xlim(-5*pi, 5*pi)

   312 ylim(-5*pi, 5*pi)

   313   \end{lstlisting}

   314 \end{frame}

   315 

   316 \begin{frame}[fragile]

   317   \frametitle{\texttt{from} \ldots \texttt{import} - conventional way!}

   318   \small

   319   \begin{lstlisting}

   320 import scipy

   321 import pylab

   322 

   323 x = scipy.linspace(-5*scipy.pi, 5*scipy.pi, 500)

   324 pylab.plot(x, x, 'b')

   325 pylab.plot(x, -x, 'b')

   326 pylab.plot(x, scipy.sin(x), 'g', linewidth=2)

   327 pylab.plot(x, x*scipy.sin(x), 'r', linewidth=3)

   328 pylab.legend(['x', '-x', 'sin(x)', 'xsin(x)'])

   329 pylab.annotate('origin', xy = (0, 0))

   330 pylab.xlim(-5*scipy.pi, 5*scipy.pi)

   331 pylab.ylim(-5*scipy.pi, 5*scipy.pi)

   332   \end{lstlisting}

   333 \end{frame}

   178     \frametitle{3D visualization}

   336   \frametitle{Modules: Standard library}

   179     \Large

   337   \begin{itemize}

   180     \begin{center}

   338   \item Very powerful, ``Batteries included''

   181         Harder but important

   339   \item Some standard modules:

   182     \end{center}

   340     \begin{itemize}

   341     \item Math: \typ{math}, \typ{random}

   342     \item Internet access: \typ{urllib2}, \typ{smtplib}

   343     \item System, Command line arguments: \typ{sys}

   344     \item Operating system interface: \typ{os}

   345     \item Regular expressions: \typ{re}

   346     \item Compression: \typ{gzip}, \typ{zipfile}, and \typ{tarfile}

   347     \item And a whole lot more!

   348     \end{itemize}

   349   \item Check out the Python Library reference:

   350     \url{http://docs.python.org/library/}

   351   \end{itemize}

   352 \inctime{5}

   353 \end{frame}

   354 

   355 \begin{frame}[fragile]

   356   \frametitle{Modules of special interest}

   357   \begin{description}[matplotlibfor2d]

   358     \item[\texttt{pylab}] Easy, interactive, 2D plotting

   359 

   360     \item[\texttt{scipy}] arrays, statistics, optimization, integration, linear

   361             algebra, Fourier transforms, signal and image processing,

   362             genetic algorithms, ODE solvers, special functions, and more

   363 

   364     \item[\texttt{Mayavi}] Easy, interactive, 3D plotting

   365   \end{description}

   366 \end{frame}

   367 

   368 \section{Objects}

   369 \begin{frame}{Everything is an Object!}

   370   \begin{itemize}

   371     \item \typ{int}

   372     \item \typ{float}

   373     \item \typ{str}

   374     \item \typ{list}

   375     \item \typ{tuple}

   376     \item \typ{string}

   377     \item \typ{dictionary}

   378     \item \typ{function}

   379     \item User defined class is also an object!

   380   \end{itemize}

   381 \end {frame}

   382 

   383 \begin{frame}[fragile]

   384 \frametitle{Using Objects}

   385   \begin{itemize}

   386     \item Creating Objects

   387     \begin{itemize}

   388       \item Initialization

   389     \end{itemize}

   390     \begin{lstlisting}

   391 In []: a = str()

   392 

   393 In []: b = "Hello World"

   394     \end{lstlisting}

   395     \item Object Manipulation

   396     \begin{itemize}

   397       \item Object methods

   398       \item ``.'' operator

   399     \end{itemize}

   400   \begin{lstlisting}

   401 In []: "Hello World".split()

   402 Out[]: ['Hello', 'World']

   403     \end{lstlisting}

   404   \end{itemize}

   405 \end{frame}

   406 

   407 \begin{frame}[fragile]

   408   \frametitle{Objects provide consistency}

   409   \small

   410   \begin{lstlisting}

   411 for element in (1, 2, 3):

   412     print element

   413 for key in {'one':1, 'two':2}:

   414     print key

   415 for char in "123":

   416     print char

   417 for line in open("myfile.txt"):

   418     print line

   419 for line in urllib2.urlopen('http://site.com'):

   420     print line

   421   \end{lstlisting}

   422   \inctime{10}

   186     \frametitle{Is this Graphics?}

   426   \frametitle{What did we learn?}

   187     \Large

   427   \begin{itemize}

   188     \begin{center}

   428     \item Functions: Default and Keyword arguments

   189         Visualization is about data!

   429     \item Modules

   190     \end{center}

   430     \item Objects

   191 \end{frame}

   192 

   193 \begin{frame}

   194     \frametitle{Examples: trajectory in space}

   195     \Large

   196     \begin{center}

   197         \pgfimage[width=2.5in]{MEDIA/m2/mlab/plot3d_ex}

   198     \end{center}

   199 \end{frame}

   200 

   201 \begin{frame}

   202     \frametitle{Examples: Fire in a room}

   203     \Large

   204     \begin{center}

   205         Demo of data

   206     \end{center}

   207 \inctime{10}

   208 \end{frame}

   209 

   210 \section{Tools available}

   211 

   212 \subsection{mlab}

   213 

   214 \begin{frame}

   215     {Overview}

   216     \Large

   217     \begin{itemize}

   218         \item Simple

   219         \item Convenient

   220         \item Full-featured

   221     \end{itemize}

   222 \end{frame}

   223 

   224 \begin{frame}[fragile]

   225 

   226     \frametitle{Getting started}

   227     \myemph{\Large Vanilla:}

   228     \begin{lstlisting}[language=bash]

   229         $ ipython -wthread

   230     \end{lstlisting}

   231     \myemph{\Large with Pylab:}

   232     \begin{lstlisting}[language=bash]

   233         $ ipython -pylab -wthread

   234     \end{lstlisting}

   235 \end{frame}

   236 

   237 \begin{frame}[fragile]

   238     \frametitle{Using mlab}

   239 

   240     \begin{lstlisting}

   241 In []:from enthought.mayavi import mlab

   242     \end{lstlisting}

   243 

   244     \vspace*{0.5in}

   245 

   246     \myemph{\Large Try these}

   247 

   248     \vspace*{0.25in}

   249 

   250     \begin{lstlisting}

   251 In []: mlab.test_<TAB>

   252 In []: mlab.test_contour3d()

   253 In []: mlab.test_contour3d??

   254     \end{lstlisting}

   255 \end{frame}

   256 

   257 \begin{frame}

   258     {Exploring the view}

   259     \begin{columns}

   260         \column{0.6\textwidth}

   261     \pgfimage[width=3in]{MEDIA/m2/contour3d}

   262         \column{0.4\textwidth}

   263         \begin{itemize}

   264             \item Mouse

   265             \item Keyboard

   266             \item Toolbar

   267             \item Mayavi icon\pgfimage[width=0.2in]{MEDIA/m2/m2_icon}

   268         \end{itemize}

   269     \end{columns}

   270 \end{frame}

   271 

   272 \begin{frame}[fragile]

   273   \frametitle{Clearing the plot area}  

   274   \PythonCode{In []: mlab.clf()}

   275 \end{frame}

   276 

   277 \begin{frame}[fragile]

   278     \frametitle{\mlab\ plotting functions}

   279     \begin{columns}

   280         \column{0.25\textwidth}

   281         \myemph{\Large 0D data}

   282         \column{0.5\textwidth}

   283     \pgfimage[width=2in]{MEDIA/m2/mlab/points3d_ex}

   284     \end{columns}

   285 

   286     \begin{lstlisting}

   287 In []: t = linspace(0, 2*pi, 50)

   288 In []: u = cos(t) * pi

   289 In []: x, y, z = sin(u), cos(u), sin(t)

   290     \end{lstlisting}

   291     \emphbar{\PythonCode{In []: mlab.points3d(x, y, z)}}

   292 \end{frame}

   293 

   294 \begin{frame}

   295   \begin{columns}

   296         \column{0.25\textwidth}

   297         \myemph{\Large 1D data}

   298         \column{0.5\textwidth}

   299         \pgfimage[width=2.5in]{MEDIA/m2/mlab/plot3d_ex}

   300   \end{columns}

   301   \PythonCode{In []: mlab.clf()}

   302   \emphbar{\PythonCode{In []: mlab.plot3d(x, y, z, t)}}

   303 

   304     Plots lines between the points

   305     

   306 \end{frame}

   307 

   308 \begin{frame}[fragile]

   309     \begin{columns}

   310         \column{0.25\textwidth}

   311         \myemph{\Large 2D data}

   312         \column{0.5\textwidth}

   313         \pgfimage[width=2in]{MEDIA/m2/mlab/surf_ex}

   314     \end{columns}            

   315     \begin{lstlisting}

   316 In []: x, y = mgrid[-3:3:100j,-3:3:100j]

   317 In []: z = sin(x*x + y*y)

   318     \end{lstlisting}

   319 

   320     \emphbar{\PythonCode{In []: mlab.surf(x, y, z)}}

   321 

   322     \alert{Assumes the points are rectilinear}

   323 

   324 \end{frame}

   325 

   326 \begin{frame}[fragile]

   327   \frametitle{mgrid}

   328   \begin{lstlisting}

   329 In []: mgrid[0:3,0:3]

   330 Out[]: 

   331 array([[[0, 0, 0],

   332         [1, 1, 1],

   333         [2, 2, 2]],

   334 

   335        [[0, 1, 2],

   336         [0, 1, 2],

   337         [0, 1, 2]]])

   338 

   339 In []: mgrid[-1:1:5j]

   340 Out[]: array([-1., -0.5,  0.,  0.5,  1.])

   341 \end{lstlisting}

   342 \end{frame}

   343 

   344 \begin{frame}[fragile]

   345   \frametitle{Example}

   346   \begin{lstlisting}

   347 In []: x, y = mgrid[-1:1:5j, -1:1:5j]

   348 In []: z = x*x + y*y

   349 

   350 In []: z

   351 Out[]: 

   352 array([[ 2.  , 1.25, 1.  , 1.25, 2.  ],

   353        [ 1.25, 0.5 , 0.25, 0.5 , 1.25],

   354        [ 1.  , 0.25, 0.  , 0.25, 1.  ],

   355        [ 1.25, 0.5 , 0.25, 0.5 , 1.25],

   356        [ 2.  , 1.25, 1.  , 1.25, 2.  ]])

   357 \end{lstlisting}

   358 \end{frame}

   359 

   360 \begin{frame}[fragile]

   361     \myemph{\Large 2D data: \texttt{mlab.mesh}}

   362     \vspace*{0.25in}

   363 

   364     \emphbar{\PythonCode{In []: mlab.mesh(x, y, z)}}

   365 

   366     \alert{Points needn't be regular}

   367 

   368     \vspace*{0.25in}

   369 \begin{lstlisting}

   370 In []: phi, theta = mgrid[0:pi:20j, 

   371 ...                         0:2*pi:20j]

   372 In []: x = sin(phi)*cos(theta)

   373 In []: y = sin(phi)*sin(theta)

   374 In []: z = cos(phi)

   375 In []: mlab.mesh(x, y, z, 

   376 ...           representation=

   377 ...           'wireframe')

   378 \end{lstlisting}

   379 

   380 \end{frame}

   381 

   382 \begin{frame}[fragile]

   383 

   384   \begin{columns}

   385         \column{0.25\textwidth}

   386         \myemph{\Large 3D data}

   387         \column{0.5\textwidth}

   388         \pgfimage[width=1.5in]{MEDIA/m2/mlab/contour3d}\\        

   389     \end{columns}

   390 \begin{lstlisting}

   391 In []: x, y, z = mgrid[-5:5:64j, 

   392 ...                -5:5:64j, 

   393 ...                -5:5:64j]

   394 In []: mlab.contour3d(x*x*0.5 + y*y + 

   395                    z*z*2)

   396 \end{lstlisting}

   397 \end{frame}

   398 

   399 \begin{frame}[fragile]

   400 

   401     \myemph{\Large 3D vector data: \PythonCode{mlab.quiver3d}}

   402     \vspace*{0.25in}

   403 

   404     \pgfimage[width=2in]{MEDIA/m2/mlab/quiver3d_ex}\\

   405     

   406 \begin{lstlisting}

   407 In []: mlab.test_quiver3d()

   408 \end{lstlisting}

   409 

   410 \emphbar{\PythonCode{obj = mlab.quiver3d(x, y, z, u, v, w)}}

   411 \inctime{20}

   412 \end{frame}

   413 

   414 

   415 \subsection{Mayavi2}

   416 

   417 \begin{frame}

   418   \frametitle{Introduction to Mayavi}

   419   \begin{itemize}

   420   \item Most scientists not interested in details of visualization

   421   \item Visualization of data files with a nice UI

   422   \item Interactive visualization of data (think Matlab)

   423   \item Embedding visualizations in applications

   424   \item Customization

   425   \end{itemize}

   426   \pause

   427   \begin{block}{The Goal}

   428       Provide a \alert{flexible} library/app for all of these needs!

   429   \end{block}

   430 \end{frame}

   431 

   432 \begin{frame}

   433     {Overview of features}

   434       \vspace*{-0.3in}

   435   \begin{center}    

   436     \hspace*{-0.2in}\pgfimage[width=5in]{MEDIA/m2/m2_app3_3}

   437   \end{center}    

   438 \end{frame}

   439 

   440 

   441 \begin{frame}

   442     \frametitle{Mayavi in applications}

   443       \vspace*{-0.3in}

   444   \begin{center}    

   445     \hspace*{-0.2in}\pgfimage[width=4.5in]{MEDIA/m2/m2_envisage}

   446   \end{center}

   447 \end{frame}

   448 

   449 \begin{frame}

   450     \frametitle{Live in your dialogs}

   451       \vspace*{0.1in}

   452   \begin{center}    

   453     \hspace*{-0.2in}\pgfimage[width=2.5in]{MEDIA/m2/mlab_tui}

   454   \end{center}

   455 \end{frame}

   456 

   457 \begin{frame}

   458     {Exploring the documentation}

   459     \begin{center}

   460     \pgfimage[width=4in]{MEDIA/m2/m2_ug_doc}

   461     \end{center}

   462 \end{frame}

   463 

   464 

   465 \begin{frame}

   466   \frametitle{Summary}

   467       \begin{itemize}

   468           \item \url{http://code.enthought.com/projects/mayavi}

   469           \item Uses VTK (\url{www.vtk.org})

   470           \item BSD license

   471           \item Linux, win32 and Mac OS X

   472           \item Highly scriptable

   473           \item Embed in Traits UIs (wxPython and PyQt4)

   474           \item Envisage Plugins

   475           \item Debian/Ubuntu/Fedora

   476           \item \alert{Pythonic}

   477       \end{itemize}

   478     

   479       \inctime{10}

   480 

   481 \end{frame}

   482 

   483 \begin{frame}

   484     {Getting hands dirty!}

   485 

   486         \begin{block}{Motivational problem}

   487         Atmospheric data of temperature over the surface of the earth.

   488         Let temperature ($T$) vary linearly with height ($z$):

   489         \begin{center}            

   490         $T = 288.15 - 6.5z$

   491         \end{center}

   492         \end{block}

   493 \end{frame}

   494 

   495 \begin{frame}[fragile]

   496     \frametitle{Simple solution}

   497 

   498     \begin{lstlisting}

   499 lat = linspace(-89, 89, 37)

   500 lon = linspace(0, 360, 37)

   501 z = linspace(0, 100, 11)

   502     \end{lstlisting}

   503 \pause

   504     \begin{lstlisting}

   505 x, y, z = mgrid[0:360:37j,-89:89:37j,

   506                 0:100:11j]

   507 t = 288.15 - 6.5*z

   508 mlab.contour3d(x, y, z, t)

   509 mlab.outline()

   510 mlab.colorbar()

   511     \end{lstlisting}

   512 \end{frame}

   513 

   514 \begin{frame}[fragile]

   515     \frametitle{Exercise: Lorenz equation}

   516     \begin{columns}

   517         \column{0.25\textwidth}

   518         \begin{eqnarray*}

   519         \frac{d x}{dt} &=& s (y-x)\\

   520         \frac{d y}{d t} &=& rx -y -xz\\

   521         \frac{d z}{d t} &=& xy - bz\\

   522         \end{eqnarray*}

   523         \column{0.25\textwidth}

   524         Let $s=10,$

   525         $r=28,$ 

   526         $b=8./3.$

   527     \end{columns}

   528     \structure{\Large Region of interest}

   529   \begin{lstlisting}

   530 x, y, z = mgrid[-50:50:20j,-50:50:20j,

   531                 -10:60:20j]

   532   \end{lstlisting}

   533 \inctime{20}

   534 

   535 \end{frame}

   536 \begin{frame}[fragile]

   537     \frametitle{Solution}

   538   \begin{lstlisting}

   539 def lorenz(x,y,z,s=10.,r=28.,b=8./3.):

   540     u = s*(y-x)

   541     v = r*x-y-x*z

   542     w = x*y-b*z

   543     return u,v,w

   544 x,y,z = mgrid [-50:50:20j,-50:50:20j,

   545                     -10:60:20j ]

   546 u,v,w = lorenz( x , y , z )

   547 # Your plot here

   548 #

   549 mlab.show()

   550 

   551   \end{lstlisting}

   552 \end{frame}

   553 

   554 \begin{frame}

   555   \frametitle{We have covered:}

   556   \begin{itemize}

   557   \item Need of visualization.

   558   \item Using mlab to create 3 D plots.

   559   \item Mayavi Toolkit.