diff options
| -rw-r--r-- | day1/session1.tex | 4 | ||||
| -rw-r--r-- | day1/session3.tex | 31 | ||||
| -rw-r--r-- | day1/session5.tex | 321 | ||||
| -rw-r--r-- | day1/session6.tex | 85 | ||||
| -rw-r--r-- | day2/session1.tex | 43 | ||||
| -rw-r--r-- | day2/session2.tex | 522 |
6 files changed, 853 insertions, 153 deletions
diff --git a/day1/session1.tex b/day1/session1.tex index 6f4a4b6..b75e63d 100644 --- a/day1/session1.tex +++ b/day1/session1.tex @@ -223,12 +223,12 @@ Breaking out of loops \includegraphics[height=2in, interpolate=true]{data/firstplot} \column{0.8\textwidth} \begin{block}{} - \small + \begin{small} \begin{lstlisting} In []: x = linspace(0, 2*pi, 51) In []: plot(x, sin(x)) \end{lstlisting} - \small + \end{small} \end{block} \end{columns} \end{frame} diff --git a/day1/session3.tex b/day1/session3.tex index ae0eea2..69f28d5 100644 --- a/day1/session3.tex +++ b/day1/session3.tex @@ -126,6 +126,7 @@ %% % You might wish to add the option [pausesections] %% \end{frame} +\section{Statistics} \begin{frame} \frametitle{More on data processing} \begin{block}{} @@ -178,8 +179,10 @@ \item Pass/Fail (P/F) \item Withdrawn (W) \end{itemize} + \inctime{5} \end{frame} +\subsection{Data processing} \begin{frame}[fragile] \frametitle{File reading and parsing \ldots} \begin{lstlisting} @@ -188,22 +191,23 @@ for record in open('sslc1.txt'): \end{lstlisting} \end{frame} +\subsection{Dictionary} \begin{frame}[fragile] \frametitle{Dictionary: Introduction} \begin{itemize} \item lists index: 0 \ldots n \item dictionaries index using strings \end{itemize} -\begin{block}{Example} + \begin{block}{Example} d = \{ ``Hitchhiker's guide'' : 42, ``Terminator'' : ``I'll be back''\}\\ d[``Terminator''] => ``I'll be back'' -\end{block} + \end{block} \end{frame} \begin{frame}[fragile] \frametitle{Dictionary: Introduction} -\begin{lstlisting} + \begin{lstlisting} In [1]: d = {"Hitchhiker's guide" : 42, "Terminator" : "I'll be back"} @@ -215,24 +219,24 @@ Out[3]: True In [4]: "Guido" in d Out[4]: False -\end{lstlisting} + \end{lstlisting} \end{frame} \begin{frame}[fragile] \frametitle{Dictionary: Introduction} -\begin{lstlisting} + \begin{lstlisting} In [5]: d.keys() Out[5]: ['Terminator', "Hitchhiker's guide"] In [6]: d.values() Out[6]: ["I'll be back", 42] -\end{lstlisting} + \end{lstlisting} \end{frame} \begin{frame}[fragile] \frametitle{enumerate: Iterating through list indices} -\begin{lstlisting} + \begin{lstlisting} In [1]: names = ["Guido","Alex", "Tim"] In [2]: for i, name in enumerate(names): @@ -241,15 +245,16 @@ In [2]: for i, name in enumerate(names): 0 Guido 1 Alex 2 Tim -\end{lstlisting} + \end{lstlisting} + \inctime{5} \end{frame} \begin{frame}[fragile] \frametitle{Dictionary: Building parsed data} - Let our dictionary be: - \begin{lstlisting} + Let our dictionary be: + \begin{lstlisting} science = {} # is an empty dictionary - \end{lstlisting} + \end{lstlisting} \end{frame} \begin{frame}[fragile] @@ -291,6 +296,7 @@ if score > 90: \end{lstlisting} \end{frame} +\subsection{Visualizing the data} \begin{frame}[fragile] \frametitle{Pie charts} \small @@ -308,6 +314,7 @@ savefig('/tmp/science.png') \includegraphics[height=2in, interpolate=true]{data/science} \column{0.8\textwidth} \end{columns} + \inctime{5} \end{frame} \begin{frame}[fragile] @@ -381,6 +388,7 @@ savefig('/tmp/all_regions.png') \includegraphics[height=3in, interpolate=true]{data/all_regions} \end{frame} +\subsection{Obtaining stastics} \begin{frame}[fragile] \frametitle{Obtaining statistics} \begin{lstlisting} @@ -395,6 +403,7 @@ print "Mode: ", stats.mode(math_scores) print "Standard Deviation: ", std(math_scores) \end{lstlisting} + \inctime{15} \end{frame} \begin{frame}[fragile] diff --git a/day1/session5.tex b/day1/session5.tex index 8ed3d1f..3c66ad6 100644 --- a/day1/session5.tex +++ b/day1/session5.tex @@ -79,7 +79,7 @@ \author[FOSSEE] {FOSSEE} \institute[IIT Bombay] {Department of Aerospace Engineering\\IIT Bombay} -\date[] {31, October 2009\\Day 1, Session 4} +\date[] {31, October 2009\\Day 1, Session 5} %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %\pgfdeclareimage[height=0.75cm]{iitmlogo}{iitmlogo} @@ -96,13 +96,13 @@ \end{frame} } -%%\AtBeginSection[] -%%{ - %%\begin{frame}<beamer> -%% \frametitle{Outline} - %% \tableofcontents[currentsection,currentsubsection] - %%\end{frame} -%%} +\AtBeginSection[] +{ + \begin{frame}<beamer> + \frametitle{Outline} + \tableofcontents[currentsection,currentsubsection] + \end{frame} +} % If you wish to uncover everything in a step-wise fashion, uncomment % the following command: @@ -124,178 +124,277 @@ % \pausesections \end{frame} -\section{Integration} - -\subsection{Quadrature} +\section{Interpolation} \begin{frame}[fragile] -\frametitle{Quadrature} -\begin{itemize} -\item We wish to find area under a curve -\item Area under $(sin(x) + x^2)$ in $(0,1)$ -\item scipy has functions to do that -\end{itemize} -\small{\typ{In []: from scipy.integrate import quad}} +\frametitle{Interpolation} \begin{itemize} -\item Inputs - function to integrate, limits +\item Let us begin with interpolation +\item Let's use the L and T arrays and interpolate this data to obtain data at new points \end{itemize} \begin{lstlisting} -In []: x = 0 -In []: quad(sin(x)+x**2, 0, 1) +In []: L = [] +In []: T = [] +In []: for line in open('pendulum.txt'): + l, t = line.split() + L.append(float(l)) + T.append(float(t)) +In []: L = array(L) +In []: T = array(T) \end{lstlisting} -\alert{\typ{error:}} -\typ{First argument must be a callable function.} \end{frame} +%% \begin{frame}[fragile] +%% \frametitle{Interpolation \ldots} +%% \begin{small} +%% \typ{In []: from scipy.interpolate import interp1d} +%% \end{small} +%% \begin{itemize} +%% \item The \typ{interp1d} function returns a function +%% \begin{lstlisting} +%% In []: f = interp1d(L, T) +%% \end{lstlisting} +%% \item Functions can be assigned to variables +%% \item This function interpolates between known data values to obtain unknown +%% \end{itemize} +%% \end{frame} + +%% \begin{frame}[fragile] +%% \frametitle{Interpolation \ldots} +%% \begin{lstlisting} +%% In []: Ln = arange(0.1,0.99,0.005) +%% # Interpolating! +%% # The new values in range of old data +%% In []: plot(L, T, 'o', Ln, f(Ln), '-') +%% In []: f = interp1d(L, T, kind='cubic') +%% # When kind not specified, it's linear +%% # Others are ... +%% # 'nearest', 'zero', +%% # 'slinear', 'quadratic' +%% \end{lstlisting} +%% \end{frame} + \begin{frame}[fragile] -\frametitle{Functions - Definition} +\frametitle{Spline Interpolation} +\begin{small} \begin{lstlisting} -In []: def f(x): - return sin(x)+x**2 -In []: quad(f, 0, 1) +In []: from scipy.interpolate import splrep +In []: from scipy.interpolate import splev \end{lstlisting} +\end{small} \begin{itemize} -\item \typ{def} -\item arguments -\item \typ{return} +\item Involves two steps + \begin{enumerate} + \item Find out the spline curve, coefficients + \item Evaluate the spline at new points + \end{enumerate} \end{itemize} \end{frame} \begin{frame}[fragile] -\frametitle{Functions - Calling them} +\frametitle{\typ{splrep}} +To find the B-spline representation \begin{lstlisting} -In [15]: f() ---------------------------------------- +In []: tck = splrep(L, T) \end{lstlisting} -\alert{\typ{TypeError:}}\typ{f() takes exactly 1 argument} -\typ{(0 given)} +Returns +\begin{enumerate} +\item the vector of knots, +\item the B-spline coefficients +\item the degree of the spline (default=3) +\end{enumerate} +\end{frame} + +\begin{frame}[fragile] +\frametitle{\typ{splev}} +To Evaluate a B-spline and it's derivatives \begin{lstlisting} -In []: f(0) -Out[]: 0.0 -In []: f(1) -Out[]: 1.8414709848078965 +In []: Lnew = arange(0.1,1,0.005) +In []: Tnew = splev(Lnew, tck) + +#To obtain derivatives of the spline +#use der=1, 2,.. for 1st, 2nd,.. order +In []: Tnew = splev(Lnew, tck, der=1) \end{lstlisting} \end{frame} +%% \begin{frame}[fragile] +%% \frametitle{Interpolation \ldots} +%% \begin{itemize} +%% \item +%% \end{itemize} +%% \end{frame} + +\section{Differentiation} + +\begin{frame}[fragile] +\frametitle{Numerical Differentiation} +\begin{itemize} +\item Given function $f(x)$ or data points $y=f(x)$ +\item We wish to calculate $f^{'}(x)$ at points $x$ +\item Taylor series - finite difference approximations +\end{itemize} +\begin{center} +\begin{tabular}{l l} +$f(x+h)=f(x)+h.f^{'}(x)$ &Forward \\ +$f(x-h)=f(x)-h.f^{'}(x)$ &Backward +\end{tabular} +\end{center} +\end{frame} \begin{frame}[fragile] -\frametitle{Functions - Default Arguments} +\frametitle{Forward Difference} \begin{lstlisting} -In []: def f(x=1): - return sin(x)+x**2 -In []: f(10) -Out[]: 99.455978889110625 -In []: f(1) -Out[]: 1.8414709848078965 -In []: f() -Out[]: 1.8414709848078965 +In []: x = linspace(0, 2*pi, 100) +In []: y = sin(x) +In []: deltax = x[1] - x[0] \end{lstlisting} +Obtain the finite forward difference of y \end{frame} \begin{frame}[fragile] -\frametitle{Functions - Keyword Arguments} +\frametitle{Forward Difference \ldots} \begin{lstlisting} -In []: def f(x=1, y=pi): - return sin(y)+x**2 -In []: f() -Out[]: 1.0000000000000002 -In []: f(2) -Out[]: 4.0 -In []: f(y=2) -Out[]: 1.9092974268256817 -In []: f(y=pi/2,x=0) -Out[]: 1.0 +In []: fD = (y[1:] - y[:-1]) / deltax +In []: plot(x, y, x[:-1], fD) \end{lstlisting} +\begin{center} + \includegraphics[height=2in, interpolate=true]{data/fwdDiff} +\end{center} \end{frame} \begin{frame}[fragile] - \frametitle{More on functions} - \begin{itemize} - \item Scope of variables in the function is local - \item Mutable items are \alert{passed by reference} - \item First line after definition may be a documentation string - (\alert{recommended!}) - \item Function definition and execution defines a name bound to the - function - \item You \emph{can} assign a variable to a function! - \end{itemize} +\frametitle{Example} +\begin{itemize} +\item Given x, y positions of a particle in \typ{pos.txt} +\item Find velocity \& acceleration in x, y directions +\end{itemize} +\small{ +\begin{center} +\begin{tabular}{| c | c | c |} +\hline +$X$ & $Y$ \\ \hline +0. & 0.\\ \hline +0.25 & 0.47775\\ \hline +0.5 & 0.931\\ \hline +0.75 & 1.35975\\ \hline +1. & 1.764\\ \hline +1.25 & 2.14375\\ \hline +\vdots & \vdots\\ \hline +\end{tabular} +\end{center}} \end{frame} \begin{frame}[fragile] -\frametitle{Quadrature \ldots} -\begin{lstlisting} -In []: quad(f, 0, 1) -\end{lstlisting} -Returns the integral and an estimate of the absolute error in the result. +\frametitle{Example \ldots} \begin{itemize} -\item Use \typ{dblquad} for Double integrals -\item Use \typ{tplquad} for Triple integrals +\item Read the file +\item Obtain an array of x, y +\item Obtain velocity and acceleration +\item use \typ{deltaT = 0.05} \end{itemize} +\begin{lstlisting} +In []: X = [] +In []: Y = [] +In []: for line in open('location.txt'): + .... points = line.split() + .... X.append(float(points[0])) + .... Y.append(float(points[1])) +In []: S = array([X, Y]) +\end{lstlisting} \end{frame} -\subsection{ODEs} \begin{frame}[fragile] -\frametitle{ODE Integration} -We shall use the simple ODE of a simple pendulum. -\begin{equation*} -\ddot{\theta} = -\frac{g}{L}sin(\theta) -\end{equation*} +\frametitle{Example \ldots} \begin{itemize} -\item This equation can be written as a system of two first order ODEs +\item use \typ{deltaT = 0.05} \end{itemize} -\begin{align} -\dot{\theta} &= \omega \\ -\dot{\omega} &= -\frac{g}{L}sin(\theta) \\ - \text{At}\ t &= 0 : \nonumber \\ - \theta = \theta_0\quad & \&\quad \omega = 0 \nonumber -\end{align} +\begin{lstlisting} +In []: deltaT = 0.05 + +In []: v = (S[:,1:]-S[:,:-1])/deltaT + +In []: a = (v[:,1:]-v[:,:-1])/deltaT +\end{lstlisting} +Try Plotting the position, velocity \& acceleration. \end{frame} +\section{Quadrature} + \begin{frame}[fragile] -\frametitle{Solving ODEs using SciPy} +\frametitle{Quadrature} +\begin{itemize} +\item We wish to find area under a curve +\item Area under $(sin(x) + x^2)$ in $(0,1)$ +\item scipy has functions to do that +\end{itemize} +\begin{small} + \typ{In []: from scipy.integrate import quad} +\end{small} \begin{itemize} -\item We use the \typ{odeint} function from scipy to do the integration -\item Define a function as below +\item Inputs - function to integrate, limits \end{itemize} \begin{lstlisting} -In []: def pend_int(unknown, t, p): - .... theta, omega = unknown - .... g, L = p - .... f=[omega, -(g/L)*sin(theta)] - .... return f - .... +In []: x = 0 +In []: quad(sin(x)+x**2, 0, 1) \end{lstlisting} +\begin{small} +\alert{\typ{error:}} +\typ{First argument must be a callable function.} +\end{small} \end{frame} \begin{frame}[fragile] -\frametitle{Solving ODEs using SciPy \ldots} +\frametitle{Functions - Definition} +We have been using them all along. Now let's see how to define them. +\begin{lstlisting} +In []: def f(x): + return sin(x)+x**2 +In []: quad(f, 0, 1) +\end{lstlisting} \begin{itemize} -\item \typ{t} is the time variable \\ -\item \typ{p} has the constants \\ -\item \typ{initial} has the initial values +\item \typ{def} +\item name +\item arguments +\item \typ{return} \end{itemize} +\end{frame} + +\begin{frame}[fragile] +\frametitle{Functions - Calling them} +\begin{lstlisting} +In [15]: f() +--------------------------------------- +\end{lstlisting} +\alert{\typ{TypeError:}}\typ{f() takes exactly 1 argument} +\typ{(0 given)} \begin{lstlisting} -In []: t = linspace(0, 10, 101) -In []: p=(-9.81, 0.2) -In []: initial = [10*2*pi/360, 0] +In []: f(0) +Out[]: 0.0 +In []: f(1) +Out[]: 1.8414709848078965 \end{lstlisting} +More on Functions later \ldots \end{frame} \begin{frame}[fragile] -\frametitle{Solving ODEs using SciPy \ldots} - -\small{\typ{In []: from scipy.integrate import odeint}} +\frametitle{Quadrature \ldots} \begin{lstlisting} -In []: pend_sol = odeint(pend_int, - initial,t, - args=(p,)) +In []: quad(f, 0, 1) \end{lstlisting} +Returns the integral and an estimate of the absolute error in the result. +\begin{itemize} +\item Look at \typ{dblquad} for Double integrals +\item Use \typ{tplquad} for Triple integrals +\end{itemize} \end{frame} \begin{frame} \frametitle{Things we have learned} \begin{itemize} + \item Interpolation + \item Differentiation \item Functions \begin{itemize} \item Definition diff --git a/day1/session6.tex b/day1/session6.tex index 1fed5d3..9ee3215 100644 --- a/day1/session6.tex +++ b/day1/session6.tex @@ -73,7 +73,7 @@ %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % Title page -\title[]{Finding Roots} +\title[]{ODEs \& Finding Roots} \author[FOSSEE] {FOSSEE} @@ -123,6 +123,68 @@ %% % You might wish to add the option [pausesections] %% \end{frame} +\section{ODEs} + +\begin{frame}[fragile] +\frametitle{ODE Integration} +We shall use the simple ODE of a simple pendulum. +\begin{equation*} +\ddot{\theta} = -\frac{g}{L}sin(\theta) +\end{equation*} +\begin{itemize} +\item This equation can be written as a system of two first order ODEs +\end{itemize} +\begin{align} +\dot{\theta} &= \omega \\ +\dot{\omega} &= -\frac{g}{L}sin(\theta) \\ + \text{At}\ t &= 0 : \nonumber \\ + \theta = \theta_0\quad & \&\quad \omega = 0 \nonumber +\end{align} +\end{frame} + +\begin{frame}[fragile] +\frametitle{Solving ODEs using SciPy} +\begin{itemize} +\item We use the \typ{odeint} function from scipy to do the integration +\item Define a function as below +\end{itemize} +\begin{lstlisting} +In []: def pend_int(unknown, t, p): + .... theta, omega = unknown + .... g, L = p + .... f=[omega, -(g/L)*sin(theta)] + .... return f + .... +\end{lstlisting} +\end{frame} + +\begin{frame}[fragile] +\frametitle{Solving ODEs using SciPy \ldots} +\begin{itemize} +\item \typ{t} is the time variable \\ +\item \typ{p} has the constants \\ +\item \typ{initial} has the initial values +\end{itemize} +\begin{lstlisting} +In []: t = linspace(0, 10, 101) +In []: p=(-9.81, 0.2) +In []: initial = [10*2*pi/360, 0] +\end{lstlisting} +\end{frame} + +\begin{frame}[fragile] +\frametitle{Solving ODEs using SciPy \ldots} +\begin{small} + \typ{In []: from scipy.integrate import odeint} +\end{small} +\begin{lstlisting} +In []: pend_sol = odeint(pend_int, + initial,t, + args=(p,)) +\end{lstlisting} +\end{frame} + +\section{Finding Roots} \begin{frame}[fragile] \frametitle{Roots of $f(x)=0$} @@ -136,8 +198,8 @@ \begin{frame}[fragile] \frametitle{Initial Estimates} \begin{itemize} -\item Find the roots of $cosx-x^2$ between $-\pi/2$ and $\pi/2$ -\item We shall use a crude method to get an initial estimate first +\item Find roots of $cosx-x^2$ in $(-\pi/2, \pi/2)$ +\item How to get a rough initial estimate? \end{itemize} \begin{enumerate} \item Check for change of signs of $f(x)$ in the given interval @@ -288,15 +350,28 @@ \begin{frame}[fragile] \frametitle{Scipy Methods \dots} -\small{ +\begin{small} \begin{lstlisting} In []: from scipy.optimize import fixed_point In []: from scipy.optimize import bisect In []: from scipy.optimize import newton -\end{lstlisting}} +\end{lstlisting} +\end{small} \end{frame} +\begin{frame} + \frametitle{Things we have learned} + \begin{itemize} + \item Solving ODEs + \item Finding Roots + \begin{itemize} + \item Estimating Interval + \item Newton Raphson + \item Scipy methods + \end{itemize} + \end{itemize} +\end{frame} \end{document} diff --git a/day2/session1.tex b/day2/session1.tex index 5fb42e0..721b4ce 100644 --- a/day2/session1.tex +++ b/day2/session1.tex @@ -182,6 +182,7 @@ Out[3]: True In [4]: f and t Out[4]: False \end{lstlisting} + \inctime{5} \end{frame} \subsection{Strings} @@ -252,10 +253,8 @@ In [1]: x, y = 1, 1.234 In [2]: 'x is %s, y is %s' %(x, y) Out[2]: 'x is 1, y is 1.234' \end{lstlisting} -\emphbar{ -\url{http://docs.python.org/library/stdtypes.html}\\ -} -\inctime{10} + \emphbar{\url{http://docs.python.org/library/stdtypes.html}} + \inctime{10} \end{frame} \section{Operators} @@ -338,7 +337,6 @@ Out[4]: True In [5]: pos + neg != zer Out[5]: False \end{lstlisting} -\inctime{5} \end{frame} \begin{frame}[fragile] @@ -378,19 +376,6 @@ In [6]: a = "# This is not a comment!" \inctime{15} \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} - \section{Simple IO} \begin{frame}{Simple IO} \begin{block} @@ -419,7 +404,7 @@ In [6]: a = "# This is not a comment!" \subsection{Basic Conditional flow} \begin{frame}[fragile] \frametitle{\typ{If...elif...else} example} -\begin{lstlisting} + \begin{lstlisting} x = int(raw_input("Enter an integer:")) if x < 0: print 'Be positive!' @@ -429,7 +414,8 @@ elif x == 1: print 'Single' else: print 'More' -\end{lstlisting} + \end{lstlisting} + \inctime{10} \end{frame} \subsection{Basic Looping} @@ -470,7 +456,7 @@ In []: for i in range(5): 3 9 4 16 \end{lstlisting} -\inctime{15} +\inctime{5} \end{frame} \subsection{Exercises} @@ -496,10 +482,9 @@ In []: for i in range(5): \item It appears that for all starting values there is a cycle of 4, 2, 1 at which the procedure loops. \end{enumerate} Write a program that accepts the starting value and prints out the Collatz sequence. - \end{frame} -\begin{frame}[fragile]{Problem 1.4} +\begin{frame}[fragile]{Problem 1.3} Write a program that prints the following pyramid on the screen. \begin{lstlisting} 1 @@ -510,7 +495,17 @@ In []: for i in range(5): The number of lines must be obtained from the user as input.\\ \pause \emphbar{When can your code fail?} -\only<2->{\inctime{20}} +\only<2->{\inctime{10}} +\end{frame} + +\begin{frame}[fragile] + \frametitle{What did we learn?} + \begin{itemize} + \item Basic data types + \item Arithematic, logical and relational operations + \item Conditional structures + \item Loops + \end{itemize} \end{frame} \end{document} diff --git a/day2/session2.tex b/day2/session2.tex new file mode 100644 index 0000000..5b1553d --- /dev/null +++ b/day2/session2.tex @@ -0,0 +1,522 @@ +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +%Tutorial slides on Python. +% +% Author: Prabhu Ramachandran <prabhu at aero.iitb.ac.in> +% Copyright (c) 2005-2009, Prabhu Ramachandran +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + +\documentclass[14pt,compress]{beamer} +%\documentclass[draft]{beamer} +%\documentclass[compress,handout]{beamer} +%\usepackage{pgfpages} +%\pgfpagesuselayout{2 on 1}[a4paper,border shrink=5mm] + +% Modified from: generic-ornate-15min-45min.de.tex +\mode<presentation> +{ + \usetheme{Warsaw} + \useoutertheme{split} + \setbeamercovered{transparent} +} + +\usepackage[english]{babel} +\usepackage[latin1]{inputenc} +%\usepackage{times} +\usepackage[T1]{fontenc} + +% Taken from Fernando's slides. +\usepackage{ae,aecompl} +\usepackage{mathpazo,courier,euler} +\usepackage[scaled=.95]{helvet} + +\definecolor{darkgreen}{rgb}{0,0.5,0} + +\usepackage{listings} +\lstset{language=Python, + basicstyle=\ttfamily\bfseries, + commentstyle=\color{red}\itshape, + stringstyle=\color{darkgreen}, + showstringspaces=false, + keywordstyle=\color{blue}\bfseries} + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +% Macros +\setbeamercolor{emphbar}{bg=blue!20, fg=black} +\newcommand{\emphbar}[1] +{\begin{beamercolorbox}[rounded=true]{emphbar} + {#1} + \end{beamercolorbox} +} +\newcounter{time} +\setcounter{time}{0} +\newcommand{\inctime}[1]{\addtocounter{time}{#1}{\tiny \thetime\ m}} + +\newcommand{\typ}[1]{\texttt{#1}} + +\newcommand{\kwrd}[1]{ \texttt{\textbf{\color{blue}{#1}}} } + +%%% This is from Fernando's setup. +% \usepackage{color} +% \definecolor{orange}{cmyk}{0,0.4,0.8,0.2} +% % Use and configure listings package for nicely formatted code +% \usepackage{listings} +% \lstset{ +% language=Python, +% basicstyle=\small\ttfamily, +% commentstyle=\ttfamily\color{blue}, +% stringstyle=\ttfamily\color{orange}, +% showstringspaces=false, +% breaklines=true, +% postbreak = \space\dots +% } + + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +% Title page +\title[Basic Python]{Python:\\A formal approach} + +\author[FOSSEE Team] {The FOSSEE Group} + +\institute[IIT Bombay] {Department of Aerospace Engineering\\IIT Bombay} +\date[] {1, November 2009\\Day 2, Session 2} +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + +%\pgfdeclareimage[height=0.75cm]{iitmlogo}{iitmlogo} +%\logo{\pgfuseimage{iitmlogo}} + + +%% Delete this, if you do not want the table of contents to pop up at +%% the beginning of each subsection: +\AtBeginSubsection[] +{ + \begin{frame}<beamer> + \frametitle{Outline} + \tableofcontents[currentsection,currentsubsection] + \end{frame} +} + +\AtBeginSection[] +{ + \begin{frame}<beamer> + \frametitle{Outline} + \tableofcontents[currentsection,currentsubsection] + \end{frame} +} + +% If you wish to uncover everything in a step-wise fashion, uncomment +% the following command: +%\beamerdefaultoverlayspecification{<+->} + +%\includeonlyframes{current,current1,current2,current3,current4,current5,current6} + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +% DOCUMENT STARTS +\begin{document} + +\begin{frame} + \titlepage +\end{frame} + +\begin{frame} + \frametitle{Outline} + \tableofcontents + % You might wish to add the option [pausesections] +\end{frame} + +\section{Data structures} +\subsection{Lists} +\begin{frame}[fragile] + \frametitle{Lists} +\begin{block}{We already know that} + \begin{lstlisting} +num = [1, 2, 3, 4, 5, 6, 7, 8] + \end{lstlisting} +\centerline{is a list} +\end{block} +\end{frame} + +\begin{frame}[fragile] + \frametitle{Lists: methods} + \begin{lstlisting} +In []: num.reverse() +In []: num +Out[]: [8, 7, 6, 5, 4, 3, 2, 1] + +In []: num.extend([0, -1, -2]) +In []: num +Out[]: [8, 7, 6, 5, 4, 3, 2, 1, 0, -1] + +In []: num.remove(0) +In []: num +Out[]: [8, 7, 6, 5, 4, 3, 2, 1, -1] + \end{lstlisting} +\end{frame} + +\begin{frame}[fragile] +\frametitle{List containership} +\begin{lstlisting} +In []: a = 8 + +In []: a in num +Out[]: True + +In []: b = 10 +In []: b in num +Out[]: False + +In []: b not in num +Out[]: True +\end{lstlisting} +\end{frame} + +\subsection{Tuples} +\begin{frame}[fragile] +\frametitle{Tuples: Immutable lists} +\begin{lstlisting} +In []: t = (1, 2, 3, 4, 5, 6, 7, 8) +In []: t[0] + t[3] + t[-1] +Out[]: 13 +\end{lstlisting} +\begin{block}{Note:} +\begin{itemize} + \item Tuples are immutable - cannot be changed +\end{itemize} +\end{block} + \inctime{10} +\end{frame} + +\begin{frame} + {A classic problem} + \begin{block} + {Interchange values} + How to interchange values of two variables? + \end{block} + \pause + \begin{block}{Note:} + This Python idiom works for all types of variables.\\ +They need not be of the same type! + \end{block} +\end{frame} + +\subsection{Dictionaries} +\begin{frame}[fragile] + \frametitle{Dictionaries: Recall} + \begin{lstlisting} +In []: player = {'Mat': 134,'Inn': 233, + 'Runs': 10823, 'Avg': 52.53} + +In []: player['Avg'] +Out[]: 52.530000000000001 + \end{lstlisting} + \begin{block}{Note!} + Duplicate keys are not allowed!\\ + Dictionaries are iterable through keys. + \end{block} +\end{frame} + +\begin{frame} {Problem Set 2.1: Problem 2.1.1} +You are given date strings of the form ``29, Jul 2009'', or ``4 January 2008''. In other words a number a string and another number, with a comma sometimes separating the items.Write a function that takes such a string and returns a tuple (yyyy, mm, dd) where all three elements are ints. +\end{frame} + +\subsection{Set} +\begin{frame}[fragile] + \frametitle{Set} + \begin{itemize} + \item Simplest container, mutable + \item No ordering, no duplicates + \item usual suspects: union, intersection, subset \ldots + \item >, >=, <, <=, in, \ldots + \end{itemize} + \begin{lstlisting} +>>> f10 = set([1,2,3,5,8]) +>>> p10 = set([2,3,5,7]) +>>> f10|p10 +set([1, 2, 3, 5, 7, 8]) +>>> f10&p10 +set([2, 3, 5]) +>>> f10-p10 +set([8, 1]) +\end{lstlisting} +\end{frame} + +\begin{frame}[fragile] + \frametitle{Set} + \begin{lstlisting} +>>> p10-f10, f10^p10 +set([7]), set([1, 7, 8]) +>>> set([2,3]) < p10 +True +>>> set([2,3]) <= p10 +True +>>> 2 in p10 +True +>>> 4 in p10 +False +>>> len(f10) +5 +\end{lstlisting} +\end{frame} + +\begin{frame} + \frametitle{Problem set 2.2} + \begin{description} + \item[2.2.1] Given a dictionary of the names of students and their marks, identify how many duplicate marks are there? and what are these? + \item[2.2.2] Given a string of the form ``4-7, 9, 12, 15'' find the numbers missing in this list for a given range. +\end{description} +\inctime{15} +\end{frame} + +\section{Functions} +\begin{frame}[fragile] + \frametitle{Functions} + \begin{itemize} + \item \kwrd{def} - keyword to define a function + \item Arguments are local to a function + \item Docstrings are important! + \item Functions can return multiple values + \end{itemize} +\end{frame} + +\begin{frame}[fragile] + \frametitle{Functions: example} + \begin{lstlisting} +def signum( r ): + """returns 0 if r is zero + -1 if r is negative + +1 if r is positive""" + if r < 0: + return -1 + elif r > 0: + return 1 + else: + return 0 + \end{lstlisting} +\end{frame} + +\begin{frame}[fragile] + {What does this function do?} +\begin{lstlisting} +def what( n ): + i = 1 + while i * i < n: + i += 1 + return i * i == n, i + \end{lstlisting} +\end{frame} + +\subsection{Default arguments} +\begin{frame}[fragile] + \frametitle{Functions: default arguments} + \small + \begin{lstlisting} +def ask_ok(prompt, complaint='Yes or no!'): + while True: + ok = raw_input(prompt) + if ok in ('y', 'ye', 'yes'): + return True + if ok in ('n', 'no', 'nop', + 'nope'): + return False + print complaint + +ask_ok('?') +ask_ok('?', '[Y/N]') + \end{lstlisting} +\end{frame} + +\subsection{Built-in functions} +\begin{frame} + {Before writing a function} + \begin{itemize} + \item Variety of builtin functions are available + \item \typ{abs, any, all, len, max, min} + \item \typ{pow, range, sum, type} + \item Refer here: + \url{http://docs.python.org/library/functions.html} + \end{itemize} + \inctime{10} +\end{frame} + +\subsection{Exercises} +\begin{frame}{Problem set 3: Problem 3.1} + Write a function to return the gcd of two numbers. +\end{frame} + +\begin{frame}{Problem 3.2} +Write a program to print all primitive pythagorean triads (a, b, c) where a, b are in the range 1---100 \\ +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. +\end{frame} + +\begin{frame}{Problem 3.3} + 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).} +\inctime{15} +\end{frame} + +\section{Modules} +\begin{frame}[fragile] + {Modules} +\begin{lstlisting} +>>> sqrt(2) +Traceback (most recent call last): + File "<stdin>", line 1, in <module> +NameError: name 'sqrt' is not defined +>>> import math +>>> math.sqrt(2) +1.4142135623730951 +\end{lstlisting} +\end{frame} + +\begin{frame}[fragile] + {Modules} + \begin{itemize} + \item The \kwrd{import} keyword ``loads'' a module + \item One can also use: + \begin{lstlisting} +>>> from math import sqrt +>>> from math import * + \end{lstlisting} + \item What is the difference? + \item \alert{Use the latter only in interactive mode} + \end{itemize} + \emphbar{Package hierarchies} + \begin{lstlisting} +>>> from os.path import exists + \end{lstlisting} +\end{frame} + +\begin{frame} + \frametitle{Modules: Standard library} + \begin{itemize} + \item Very powerful, ``Batteries included'' + \item Some standard modules: + \begin{itemize} + \item Math: \typ{math}, \typ{random} + \item Internet access: \typ{urllib2}, \typ{smtplib} + \item System, Command line arguments: \typ{sys} + \item Operating system interface: \typ{os} + \item Regular expressions: \typ{re} + \item Compression: \typ{gzip}, \typ{zipfile}, and \typ{tarfile} + \item And a whole lot more! + \end{itemize} + \item Check out the Python Library reference: + \url{http://docs.python.org/library/} + \end{itemize} +\inctime{5} +\end{frame} + +\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{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}{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}{Comments} + \begin{itemize} + \item No comments better than contradicting comments + \item Block comments + \item Inline comments + \end{itemize} +\end{frame} + +\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{Objects} +\begin{frame}{Objects in general} + \begin{itemize} + \item What is an Object? (Types and classes) + \item identity + \item type + \item method + \end{itemize} +\end{frame} + +\begin{frame}{Almost everything is an Object!} + \begin{itemize} + \item \typ{list} + \item \typ{tuple} + \item \typ{string} + \item \typ{dictionary} + \item \typ{function} + \item Of course, user defined class objects! + \end{itemize} +\end {frame} + +\begin{frame}{Using Objects} + \begin{itemize} + \item Creating Objects: Initialization + \item Object Manipulation: Object methods and ``.'' operator + \end{itemize} +\end{frame} + +\begin{frame}[fragile] + \frametitle{Objects provide consistency} + \small + \begin{lstlisting} +for element in (1, 2, 3): + print element +for key in {'one':1, 'two':2}: + print key +for char in "123": + print char +for line in open("myfile.txt"): + print line +for line in urllib2.urlopen('http://site.com'): + print line + \end{lstlisting} +\inctime{10} +\end{frame} + +\begin{frame} + \frametitle{What did we learn?} + \begin{itemize} + \item Lists, Tuples, Dictionaries, Sets: creation and manipulation + \item More about functions + \item Coding style + \item Objects: creation and manipulation + \end{itemize} +\end{frame} + +\end{document} |