--- a/day2/session4.tex Fri Nov 06 18:33:08 2009 +0530
+++ b/day2/session4.tex Fri Nov 06 18:36:42 2009 +0530
@@ -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}
-
+\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{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}
-
-\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}
-\end{frame}
-
-\begin{frame}
- \frametitle{Examples: trajectory in space}
- \Large
- \begin{center}
- \pgfimage[width=2.5in]{MEDIA/m2/mlab/plot3d_ex}
- \end{center}
-\end{frame}
-
-\begin{frame}
- \frametitle{Examples: Fire in a room}
- \Large
- \begin{center}
- Demo of data
- \end{center}
-\inctime{10}
+\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}
-\section{Tools available}
-
-\subsection{mlab}
+\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)
-\begin{frame}
- {Overview}
- \Large
- \begin{itemize}
- \item Simple
- \item Convenient
- \item Full-featured
- \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}
+ 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}[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}
+ \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}
-\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}
+\section{Coding Style}
+\begin{frame}{Readability and Consistency}
+ \begin{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{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{\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}
+ \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{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)}}
+\begin{frame}{Comments}
+ \begin{itemize}
+ \item No comments better than contradicting comments
+ \item Block comments
+ \item Inline comments
+ \end{itemize}
+\end{frame}
- Plots lines between the points
-
+\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{Errors}
+ \begin{lstlisting}
+In []: while True print 'Hello world'
+ \end{lstlisting}
+\pause
+ \begin{lstlisting}
+ File "<stdin>", line 1, in ?
+ while True print 'Hello world'
+ ^
+SyntaxError: invalid syntax
+\end{lstlisting}
\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}
-
+ \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]
- \frametitle{mgrid}
- \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.])
+ \frametitle{Exceptions}
+ \begin{lstlisting}
+In []: 1 / 0
+\end{lstlisting}
+\pause
+\begin{lstlisting}
+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{Example}
+ \frametitle{Handling Exceptions}
+ Python uses \typ{try} and \typ{except} clause.
+ %%Revisiting the raw\_input
\begin{lstlisting}
-In []: x, y = mgrid[-1:1:5j, -1:1:5j]
-In []: z = x*x + y*y
+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}
-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. ]])
-\end{lstlisting}
+%% \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]
- \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}
-\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')
-\end{lstlisting}
-
-\end{frame}
-
-\begin{frame}[fragile]
-
- \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{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)
-\end{lstlisting}
+ \frametitle{Debugging effectively}
+ \begin{itemize}
+ \item Using \typ{\%debug} in IPython
+ \end{itemize}
\end{frame}
\begin{frame}[fragile]
-
- \myemph{\Large 3D vector data: \PythonCode{mlab.quiver3d}}
- \vspace*{0.25in}
+\frametitle{Debugging in IPython}
+\small
+\begin{lstlisting}
+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
- \pgfimage[width=2in]{MEDIA/m2/mlab/quiver3d_ex}\\
-
-\begin{lstlisting}
-In []: mlab.test_quiver3d()
+In []: %debug
+> mymodule.py(2)test()
+ 0 print spam
+ipdb>
\end{lstlisting}
-
-\emphbar{\PythonCode{obj = mlab.quiver3d(x, y, z, u, v, w)}}
-\inctime{20}
+\inctime{15}
\end{frame}
+\subsection{Exercise}
+\begin{frame}[fragile]
+\frametitle{Debugging: Exercise}
+\small
+\begin{lstlisting}
+science = {}
-\subsection{Mayavi2}
+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
+
+ if score > 90:
+ science[region_code] += 1
+pie(science.values(), labels=science.keys())
+savefig('science.png')
+\end{lstlisting}
+\inctime{10}
+\end{frame}
+
+%% \begin{frame}
+%% \frametitle{Testing}
+
+%% \begin{itemize}
+%% \item Writing tests is really simple!
+
+%% \item Using nose.
+
+%% \item Example!
+%% \end{itemize}
+%% \end{frame}
+
+\section{Test Driven Approach}
\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}
+ \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}[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}
- {Overview of features}
- \vspace*{-0.3in}
- \begin{center}
- \hspace*{-0.2in}\pgfimage[width=5in]{MEDIA/m2/m2_app3_3}
- \end{center}
+\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}[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{Running the tests.}
+\begin{lstlisting}
+$ nosetests palindrome.py
+.
+----------------------------------------------
+Ran 1 test in 0.001s
+
+OK
+\end{lstlisting}
\end{frame}
-
-\begin{frame}
- \frametitle{Mayavi in applications}
- \vspace*{-0.3in}
- \begin{center}
- \hspace*{-0.2in}\pgfimage[width=4.5in]{MEDIA/m2/m2_envisage}
- \end{center}
+\begin{frame}[fragile]
+ \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}
- \frametitle{Live in your dialogs}
- \vspace*{0.1in}
- \begin{center}
- \hspace*{-0.2in}\pgfimage[width=2.5in]{MEDIA/m2/mlab_tui}
- \end{center}
-\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}
- {Exploring the documentation}
- \begin{center}
- \pgfimage[width=4in]{MEDIA/m2/m2_ug_doc}
- \end{center}
-\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{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}
-
-\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}
-\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}
-\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}
-
-\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}
- \frametitle{We have covered:}
+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}
-