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diff --git a/day2/session4.tex b/day2/session4.tex index bee8030..4f286c1 100644 --- a/day2/session4.tex +++ b/day2/session4.tex @@ -74,7 +74,7 @@ \newcommand{\tvtk}{\texttt{tvtk}} \newcommand{\mlab}{\texttt{mlab}} - +\newcommand{\typ}[1]{\lstinline{#1}} \newcounter{time} \setcounter{time}{0} \newcommand{\inctime}[1]{\addtocounter{time}{#1}{\vspace*{0.1in}\tiny \thetime\ m}} @@ -95,13 +95,12 @@ %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % Title page -\title[3D Plotting]{3D data Visualization} +\title[Python Development]{Python Development} \author[FOSSEE] {FOSSEE} \institute[IIT Bombay] {Department of Aerospace Engineering\\IIT Bombay} -\date[] {1 November, 2009\\Day 2, Session 5} - +\date[] {8 November, 2009\\Day 2, Session 4} %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %\pgfdeclareimage[height=0.75cm]{iitblogo}{iitblogo} @@ -110,7 +109,8 @@ \AtBeginSection[] { \begin{frame}<beamer> - \frametitle{Outline} + \frametitle{Outline} + \Large \tableofcontents[currentsection,currentsubsection] \end{frame} } @@ -140,419 +140,423 @@ \maketitle \end{frame} -\begin{frame} - \frametitle{Outline} - \tableofcontents - % You might wish to add the option [pausesections] -\end{frame} - -\section{3D Data Visualization} - -\begin{frame} - \frametitle{What is visualization?} - \Large - \begin{center} - Visual representation of data - \end{center} -\end{frame} - - -%% \begin{frame} -%% \frametitle{Is this new?} -%% \begin{center} -%% We have moved from: -%% \end{center} -%% \begin{columns} -%% \column{} -%% \hspace*{-1in} -%% \includegraphics[width=1.75in,height=1.75in, interpolate=true]{data/3832} -%% \column{}\hspace*{-0.25in} -%% To -%% \column{} -%% \hspace*{-1in} -%% \includegraphics[width=1.75in, height=1.75in, interpolate=true]{data/torus} -%% \end{columns} -%% \end{frame} +\section{Tests: Getting started} +\begin{frame}[fragile] + \frametitle{gcd revisited!} + \begin{itemize} + \item Open gcd.py + \end{itemize} +\begin{lstlisting} + def gcd(a, b): + if a % b == 0: + return b + return gcd(b, a%b) -\begin{frame} - \frametitle{3D visualization} - \Large - \begin{center} - Harder but important - \end{center} + print gcd(15, 65) + print gcd(16, 76) +\end{lstlisting} + \begin{itemize} + \item python gcd.py + \end{itemize} \end{frame} -\begin{frame} - \frametitle{Is this Graphics?} - \Large - \begin{center} - Visualization is about data! - \end{center} +\begin{frame}[fragile] + \frametitle{Find lcm using our gcd module} + \begin{itemize} + \item Open lcm.py + \item $lcm = \frac{a*b}{gcd(a,b)}$ + \end{itemize} +\begin{lstlisting} + from gcd import gcd + def lcm(a, b): + return (a * b) / gcd(a, b) + + print lcm(14, 56) +\end{lstlisting} + \begin{itemize} + \item python lcm.py + \end{itemize} + \begin{lstlisting} +5 +4 +56 + \end{lstlisting} \end{frame} -\begin{frame} - \frametitle{Examples: trajectory in space} - \Large - \begin{center} - \pgfimage[width=2.5in]{MEDIA/m2/mlab/plot3d_ex} - \end{center} +\begin{frame}[fragile] + \frametitle{Writing stand-alone module} +Edit gcd.py file to: +\begin{lstlisting} + def gcd(a, b): + if a % b == 0: + return b + return gcd(b, a%b) + + if __name__ == "__main__": + print gcd(15, 65) + print gcd(16, 76) +\end{lstlisting} + \begin{itemize} + \item python gcd.py + \item python lcm.py + \end{itemize} \end{frame} -\begin{frame} - \frametitle{Examples: Fire in a room} - \Large - \begin{center} - Demo of data - \end{center} -\inctime{10} +\begin{frame}[fragile] + \frametitle{More use of main} + For automating tests. + \begin{lstlisting} +if __name__ == '__main__': + for line in open('numbers.txt'): + numbers = line.split() + x = int(numbers[0]) + y = int(numbers[1]) + result = (int(numbers[2])) + assert gcd(x, y) == result + \end{lstlisting} \end{frame} -\section{Tools available} - -\subsection{mlab} - -\begin{frame} - {Overview} - \Large +\section{Coding Style} +\begin{frame}{Readability and Consistency} \begin{itemize} - \item Simple - \item Convenient - \item Full-featured - \end{itemize} + \item Readability Counts!\\Code is read more often than its written. + \item Consistency! + \item Know when to be inconsistent. + \end{itemize} \end{frame} -\begin{frame}[fragile] - - \frametitle{Getting started} - \myemph{\Large Vanilla:} - \begin{lstlisting}[language=bash] - $ ipython -wthread - \end{lstlisting} - \myemph{\Large with Pylab:} - \begin{lstlisting}[language=bash] - $ ipython -pylab -wthread - \end{lstlisting} +\begin{frame}[fragile] \frametitle{A question of good style} + \begin{lstlisting} + amount = 12.68 + denom = 0.05 + nCoins = round(amount/denom) + rAmount = nCoins * denom + \end{lstlisting} + \pause + \begin{block}{Style Rule \#1} + Naming is 80\% of programming + \end{block} \end{frame} \begin{frame}[fragile] - \frametitle{Using mlab} - - \begin{lstlisting} -In []:from enthought.mayavi import mlab - \end{lstlisting} - - \vspace*{0.5in} - - \myemph{\Large Try these} - - \vspace*{0.25in} - - \begin{lstlisting} -In []: mlab.test_<TAB> -In []: mlab.test_contour3d() -In []: mlab.test_contour3d?? - \end{lstlisting} -\end{frame} - -\begin{frame} - {Exploring the view} - \begin{columns} - \column{0.6\textwidth} - \pgfimage[width=3in]{MEDIA/m2/contour3d} - \column{0.4\textwidth} - \begin{itemize} - \item Mouse - \item Keyboard - \item Toolbar - \item Mayavi icon\pgfimage[width=0.2in]{MEDIA/m2/m2_icon} - \end{itemize} - \end{columns} + \frametitle{Code Layout} + \begin{itemize} + \item Indentation + \item Tabs or Spaces?? + \item Maximum Line Length + \item Blank Lines + \item Encodings + \end{itemize} \end{frame} -\begin{frame}[fragile] - \frametitle{\mlab\ plotting functions} - \begin{columns} - \column{0.25\textwidth} - \myemph{\Large 0D data} - \column{0.5\textwidth} - \pgfimage[width=2in]{MEDIA/m2/mlab/points3d_ex} - \end{columns} - - \begin{lstlisting} -In []: t = linspace(0, 2*pi, 50) -In []: u = cos(t) * pi -In []: x, y, z = sin(u), cos(u), sin(t) - \end{lstlisting} - \emphbar{\PythonCode{In []: mlab.points3d(x, y, z)}} +\begin{frame}{Whitespaces in Expressions} + \begin{itemize} + \item When to use extraneous whitespaces?? + \item When to avoid extra whitespaces?? + \item Use one statement per line + \end{itemize} \end{frame} -\begin{frame} - \begin{columns} - \column{0.25\textwidth} - \myemph{\Large 1D data} - \column{0.5\textwidth} - \pgfimage[width=2.5in]{MEDIA/m2/mlab/plot3d_ex} - \end{columns} - \emphbar{\PythonCode{In []: mlab.plot3d(x, y, z, t)}} - - Plots lines between the points - +\begin{frame}{Comments} + \begin{itemize} + \item No comments better than contradicting comments + \item Block comments + \item Inline comments + \end{itemize} \end{frame} -\begin{frame}[fragile] - \begin{columns} - \column{0.25\textwidth} - \myemph{\Large 2D data} - \column{0.5\textwidth} - \pgfimage[width=2in]{MEDIA/m2/mlab/surf_ex} - \end{columns} - \begin{lstlisting} -In []: x, y = mgrid[-3:3:100j,-3:3:100j] -In []: z = sin(x*x + y*y) - \end{lstlisting} - - \emphbar{\PythonCode{In []: mlab.surf(x, y, z)}} - - \alert{Assumes the points are rectilinear} - +\begin{frame}{Docstrings} + \begin{itemize} + \item When to write docstrings? + \item Ending the docstrings + \item One liner docstrings + \end{itemize} +More information at PEP8: http://www.python.org/dev/peps/pep-0008/ +\inctime{5} \end{frame} +\section{Debugging} +\subsection{Errors and Exceptions} \begin{frame}[fragile] - \frametitle{mgrid} + \frametitle{Errors} + \begin{lstlisting} +In []: while True print 'Hello world' + \end{lstlisting} +\pause \begin{lstlisting} -In []: mgrid[0:3,0:3] -Out[]: -array([[[0, 0, 0], - [1, 1, 1], - [2, 2, 2]], - - [[0, 1, 2], - [0, 1, 2], - [0, 1, 2]]]) - -In []: mgrid[-1:1:5j] -Out[]: array([-1., -0.5, 0., 0.5, 1.]) + File "<stdin>", line 1, in ? + while True print 'Hello world' + ^ +SyntaxError: invalid syntax \end{lstlisting} \end{frame} \begin{frame}[fragile] - \frametitle{Example} - \begin{lstlisting} -In []: x, y = mgrid[-1:1:5j, -1:1:5j] -In []: z = x*x + y*y - -In []: z -Out[]: -array([[ 2. , 1.25, 1. , 1.25, 2. ], - [ 1.25, 0.5 , 0.25, 0.5 , 1.25], - [ 1. , 0.25, 0. , 0.25, 1. ], - [ 1.25, 0.5 , 0.25, 0.5 , 1.25], - [ 2. , 1.25, 1. , 1.25, 2. ]]) + \frametitle{Exceptions} + \begin{lstlisting} +In []: print spam +\end{lstlisting} +\pause +\begin{lstlisting} +Traceback (most recent call last): + File "<stdin>", line 1, in <module> +NameError: name 'spam' is not defined \end{lstlisting} \end{frame} \begin{frame}[fragile] - \myemph{\Large 2D data: \texttt{mlab.mesh}} - \vspace*{0.25in} - - \emphbar{\PythonCode{In []: mlab.mesh(x, y, z)}} - - \alert{Points needn't be regular} - - \vspace*{0.25in} + \frametitle{Exceptions} + \begin{lstlisting} +In []: 1 / 0 +\end{lstlisting} +\pause \begin{lstlisting} -In []: phi, theta = mgrid[0:pi:20j, -... 0:2*pi:20j] -In []: x = sin(phi)*cos(theta) -In []: y = sin(phi)*sin(theta) -In []: z = cos(phi) -In []: mlab.mesh(x, y, z, -... representation= -... 'wireframe') +Traceback (most recent call last): + File "<stdin>", line 1, in <module> +ZeroDivisionError: integer division +or modulo by zero \end{lstlisting} +\end{frame} + +\begin{frame}[fragile] + \frametitle{Handling Exceptions} + Python uses \typ{try} and \typ{except} clause. + %%Revisiting the raw\_input + \begin{lstlisting} +a = raw_input('Enter number(Q to quit):') +try: + num = int(a) + print num +except: + if a == 'Q': + print 'Exiting...' + else: + print 'Wrong input!' + \end{lstlisting} + + +\end{frame} +%% \begin{frame}[fragile] +%% \frametitle{Solving it with \typ{try} and \typ{except}} +%% \vspace{-0.2in} +%% \begin{lstlisting} +%% highest = 0 +%% for record in open('sslc1.txt'): +%% fields = record.split(';') +%% try: +%% total = 0 +%% for score_str in fields[3:8]: +%% score = int(score_str) +%% total += score +%% if total > highest: +%% highest = total +%% except: +%% pass +%% print highest +%% \end{lstlisting} +%% \end{frame} +\subsection{Strategy} +\begin{frame}[fragile] + \frametitle{Debugging effectively} + \begin{itemize} + \item \typ{print} based strategy + \item Process: + \end{itemize} +\begin{center} +\pgfimage[interpolate=true,width=5cm,height=5cm]{DebugginDiagram.png} +\end{center} \end{frame} \begin{frame}[fragile] + \frametitle{Debugging effectively} + \begin{itemize} + \item Using \typ{\%debug} in IPython + \end{itemize} +\end{frame} - \begin{columns} - \column{0.25\textwidth} - \myemph{\Large 3D data} - \column{0.5\textwidth} - \pgfimage[width=1.5in]{MEDIA/m2/mlab/contour3d}\\ - \end{columns} +\begin{frame}[fragile] +\frametitle{Debugging in IPython} +\small \begin{lstlisting} -In []: x, y, z = mgrid[-5:5:64j, -... -5:5:64j, -... -5:5:64j] -In []: mlab.contour3d(x*x*0.5 + y*y + - z*z*2) +In []: import mymodule +In []: mymodule.test() +--------------------------------------------- +NameError Traceback (most recent call last) +<ipython console> in <module>() +mymodule.py in test() + 1 def test(): +----> 2 print spam +NameError: global name 'spam' is not defined + +In []: %debug +> mymodule.py(2)test() + 0 print spam +ipdb> \end{lstlisting} +\inctime{15} \end{frame} +\subsection{Exercise} \begin{frame}[fragile] - - \myemph{\Large 3D vector data: \PythonCode{mlab.quiver3d}} - \vspace*{0.25in} - - \pgfimage[width=2in]{MEDIA/m2/mlab/quiver3d_ex}\\ - +\frametitle{Debugging: Exercise} +\small \begin{lstlisting} -In []: mlab.test_quiver3d() -\end{lstlisting} +science = {} -\emphbar{\PythonCode{obj = mlab.quiver3d(x, y, z, u, v, w)}} -\inctime{20} -\end{frame} +for record in open('sslc1.txt'): + fields = record.split(';') + region_code = fields[0].strip() + score_str = fields[6].strip() + score = int(score_str) if score_str != 'AA' + else 0 -\subsection{Mayavi2} + if score > 90: + science[region_code] += 1 -\begin{frame} - \frametitle{Introduction to Mayavi} - \begin{itemize} - \item Most scientists not interested in details of visualization - \item Visualization of data files with a nice UI - \item Interactive visualization of data (think Matlab) - \item Embedding visualizations in applications - \item Customization - \end{itemize} - \pause - \begin{block}{The Goal} - Provide a \alert{flexible} library/app for all of these needs! - \end{block} +pie(science.values(), labels=science.keys()) +savefig('science.png') +\end{lstlisting} +\inctime{10} \end{frame} -\begin{frame} - {Overview of features} - \vspace*{-0.3in} - \begin{center} - \hspace*{-0.2in}\pgfimage[width=5in]{MEDIA/m2/m2_app3_3} - \end{center} -\end{frame} +%% \begin{frame} +%% \frametitle{Testing} + +%% \begin{itemize} +%% \item Writing tests is really simple! +%% \item Using nose. -\begin{frame} - \frametitle{Mayavi in applications} - \vspace*{-0.3in} - \begin{center} - \hspace*{-0.2in}\pgfimage[width=4.5in]{MEDIA/m2/m2_envisage} - \end{center} -\end{frame} +%% \item Example! +%% \end{itemize} +%% \end{frame} +\section{Test Driven Approach} \begin{frame} - \frametitle{Live in your dialogs} - \vspace*{0.1in} - \begin{center} - \hspace*{-0.2in}\pgfimage[width=2.5in]{MEDIA/m2/mlab_tui} - \end{center} + \frametitle{Need for Testing!} + + \begin{itemize} + \item Quality + \item Regression + \item Documentation + \end{itemize} + %% \vspace*{0.25in} + %% \emphbar{It is to assure that section of code is working as it is supposed to work} \end{frame} -\begin{frame} - {Exploring the documentation} - \begin{center} - \pgfimage[width=4in]{MEDIA/m2/m2_ug_doc} - \end{center} +\begin{frame}[fragile] + \frametitle{Example} + \begin{block}{Problem Statement} + Write a function to check whether a given input + string is a palindrome. + \end{block} \end{frame} - -\begin{frame} - \frametitle{Summary} - \begin{itemize} - \item \url{http://code.enthought.com/projects/mayavi} - \item Uses VTK (\url{www.vtk.org}) - \item BSD license - \item Linux, win32 and Mac OS X - \item Highly scriptable - \item Embed in Traits UIs (wxPython and PyQt4) - \item Envisage Plugins - \item Debian/Ubuntu/Fedora - \item \alert{Pythonic} - \end{itemize} - - \inctime{10} - +\begin{frame}[fragile] + \frametitle{Function: palindrome.py} +\begin{lstlisting} +def is_palindrome(input_str): + return input_str == input_str[::-1] +\end{lstlisting} \end{frame} -\begin{frame} - {Getting hands dirty!} - - \begin{block}{Motivational problem} - Atmospheric data of temperature over the surface of the earth. - Let temperature ($T$) vary linearly with height ($z$): - \begin{center} - $T = 288.15 - 6.5z$ - \end{center} - \end{block} +\begin{frame}[fragile] + \frametitle{Test for the palindrome: palindrome.py} +\begin{lstlisting} +def test_function_normal_words(): + input = "noon" + assert is_palindrome(input) == True + +if __name__ == "main'': + test_function_normal_words() +\end{lstlisting} \end{frame} \begin{frame}[fragile] - \frametitle{Simple solution} - - \begin{lstlisting} -lat = linspace(-89, 89, 37) -lon = linspace(0, 360, 37) -z = linspace(0, 100, 11) - \end{lstlisting} -\pause - \begin{lstlisting} -x, y, z = mgrid[0:360:37j,-89:89:37j, - 0:100:11j] -t = 288.15 - 6.5*z -mlab.contour3d(x, y, z, t) -mlab.outline() -mlab.colorbar() - \end{lstlisting} + \frametitle{Running the tests.} +\begin{lstlisting} +$ nosetests palindrome.py +. +---------------------------------------------- +Ran 1 test in 0.001s + +OK +\end{lstlisting} \end{frame} \begin{frame}[fragile] - \frametitle{Exercise: Lorenz equation} - \begin{columns} - \column{0.25\textwidth} - \begin{eqnarray*} - \frac{d x}{dt} &=& s (y-x)\\ - \frac{d y}{d t} &=& rx -y -xz\\ - \frac{d z}{d t} &=& xy - bz\\ - \end{eqnarray*} - \column{0.25\textwidth} - Let $s=10,$ - $r=28,$ - $b=8./3.$ - \end{columns} - \structure{\Large Region of interest} - \begin{lstlisting} -x, y, z = mgrid[-50:50:20j,-50:50:20j, - -10:60:20j] - \end{lstlisting} -\inctime{20} - + \frametitle{Exercise: Including new tests.} +\begin{lstlisting} +def test_function_ignore_cases_words(): + input = "Noon" + assert is_palindrome(input) == True +\end{lstlisting} + \vspace*{0.25in} + Check\\ + \PythonCode{$ nosetests palindrome.py} \\ + \begin{block}{Task} + Tweak the code to pass this test. + \end{block} \end{frame} -\begin{frame}[fragile] - \frametitle{Solution} - \begin{lstlisting} -def lorenz(x,y,z,s=10.,r=28.,b=8./3.): - u = s*(y-x) - v = r*x-y-x*z - w = x*y-b*z - return u,v,w -x,y,z = mgrid [-50:50:20j,-50:50:20j, - -10:60:20j ] -u,v,w = lorenz( x , y , z ) -# Your plot here -# -mlab.show() - \end{lstlisting} -\end{frame} +%\begin{frame}[fragile] +% \frametitle{Lets write some test!} +%\begin{lstlisting} +%#for form of equation y=mx+c +%#given m and c for two equation, +%#finding the intersection point. +%def intersect(m1,c1,m2,c2): +% x = (c2-c1)/(m1-m2) +% y = m1*x+c1 +% return (x,y) +%\end{lstlisting} +% +%Create a simple test for this +% +%function which will make it fail. +% +%\inctime{15} +%\end{frame} +% + +%% \begin{frame}[fragile] +%% \frametitle{Exercise} +%% Based on Euclid's algorithm: +%% \begin{center} +%% $gcd(a,b)=gcd(b,b\%a)$ +%% \end{center} +%% gcd function can be written as: +%% \begin{lstlisting} +%% def gcd(a, b): +%% if a%b == 0: return b +%% return gcd(b, a%b) +%% \end{lstlisting} +%% \vspace*{-0.15in} +%% \begin{block}{Task} +%% \begin{itemize} +%% \item Write at least +%% two tests for above mentioned function. +%% \item Write a non recursive implementation +%% of gcd(), and test it using already +%% written tests. +%% \end{itemize} +%% \end{block} + +%% \inctime{15} +%% \end{frame} \begin{frame} - \frametitle{We have covered:} + \frametitle{Summary} +We have coverd: \begin{itemize} - \item Need of visualization. - \item Using mlab to create 3 D plots. - \item Mayavi Toolkit. + \item Following and Resolving Error Messages. + \item Exceptions. + \item Handling exceptions + \item Approach for Debugging. + \item Writting and running tests. \end{itemize} \end{frame} \end{document} - |