diff -r 3f32f679bb45 -r e5fc37a9ca96 day1/session4.tex
--- a/day1/session4.tex	Thu Nov 05 09:22:27 2009 +0530
+++ b/day1/session4.tex	Thu Nov 05 13:09:17 2009 +0530
@@ -74,7 +74,7 @@
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 % Title page
-\title[Matrices \& Equations]{Python for Science and Engg: Matrices \& Solution of equations}
+\title[Matrices \& Equations]{Python for Science and Engg: Matrices, Least Square Fit, \& Solution of equations}
 
 \author[FOSSEE] {FOSSEE}
 
@@ -128,11 +128,9 @@
 
 \begin{frame}
 \frametitle{Matrices: Introduction}
-Let us now look at matrices in detail.\\
 \alert{All matrix operations are done using \kwrd{arrays}}
 \end{frame}
 
-\subsection{Initializing}
 \begin{frame}[fragile]
 \frametitle{Matrices: Initializing}
 \begin{lstlisting}
@@ -150,28 +148,103 @@
 \end{frame}
 
 \begin{frame}[fragile]
-  \frametitle{Accessing elements of matrices}
-\begin{small}
+  \frametitle{Accessing elements}
   \begin{lstlisting}
 In []: C = array([[1,1,2],
                   [2,4,1],
                   [-1,3,7]])
+
+In []: C[1][2]
+Out[]: 1
+
 In []: C[1,2]
 Out[]: 1
 
 In []: C[1]
 Out[]: array([2, 4, 1])
+  \end{lstlisting}
+\end{frame}
 
+\begin{frame}[fragile]
+  \frametitle{Changing elements}
+  \begin{small}
+  \begin{lstlisting}
 In []: C[1,1] = -2
 In []: C
 Out[]: 
 array([[ 1,  1,  2],
        [ 2, -2,  1],
        [-1,  3,  7]])
+
+In []: C[1] = [0,0,0]
+In []: C
+Out[]: 
+array([[ 1,  1,  2],
+       [ 0,  0,  0],
+       [-1,  3,  7]])
+  \end{lstlisting}
+  \end{small}
+How to change one \alert{column}?
+\end{frame}
+
+\begin{frame}[fragile]
+  \frametitle{Slicing}
+\begin{small}
+  \begin{lstlisting}
+In []: C[:,1]
+Out[]: array([1, 0, 3])
+
+In []: C[1,:]
+Out[]: array([0, 0, 0])
+
+In []: C[0:2,:]
+Out[]: 
+array([[1, 1, 2],
+       [0, 0, 0]])
+
+In []: C[1:3,:]
+Out[]: 
+array([[ 0,  0,  0],
+       [-1,  3,  7]])
   \end{lstlisting}
 \end{small}
 \end{frame}
 
+\begin{frame}[fragile]
+  \frametitle{Slicing \ldots}
+\begin{small}
+  \begin{lstlisting}
+In []: C[:2,:]
+Out[]: 
+array([[1, 1, 2],
+       [0, 0, 0]])
+
+In []: C[1:,:]
+Out[]: 
+array([[ 0,  0,  0],
+       [-1,  3,  7]])
+
+In []: C[1:,:2]
+Out[]: 
+array([[ 0,  0],
+       [-1,  3]])
+  \end{lstlisting}
+
+\end{small}
+\end{frame}
+
+\begin{frame}[fragile]
+  \frametitle{Striding}
+  \begin{lstlisting}
+  \end{lstlisting}
+\end{frame}
+
+\begin{frame}[fragile]
+  \frametitle{Slicing \& Striding Exercises}
+  \begin{lstlisting}
+  \end{lstlisting}
+\end{frame}
+
 \subsection{Basic Operations}
 
 \begin{frame}[fragile]
@@ -279,47 +352,47 @@
 \end{small}
 \end{frame}
 
-\begin{frame}[fragile]
-\frametitle{Computing Norms}
-\begin{lstlisting}
-In []: norm(E)
-Out[]: 8.1240384046359608
-\end{lstlisting}
-\end{frame}
+%% \begin{frame}[fragile]
+%% \frametitle{Computing Norms}
+%% \begin{lstlisting}
+%% In []: norm(E)
+%% Out[]: 8.1240384046359608
+%% \end{lstlisting}
+%% \end{frame}
 
-\begin{frame}[fragile]
-  \frametitle{Singular Value Decomposition}
-  \begin{small}
-  \begin{lstlisting}
-In []: svd(E)
-Out[]: 
-(array(
-[[ -6.66666667e-01,  -1.23702565e-16,   7.45355992e-01],
- [ -3.33333333e-01,  -8.94427191e-01,  -2.98142397e-01],
- [ -6.66666667e-01,   4.47213595e-01,  -5.96284794e-01]]),
- array([ 8.,  1.,  1.]),
- array([[-0.66666667, -0.33333333, -0.66666667],
-        [-0.        ,  0.89442719, -0.4472136 ],
-        [-0.74535599,  0.2981424 ,  0.59628479]]))
-  \end{lstlisting}
-  \end{small}
-\inctime{15}
-\end{frame}
+%% \begin{frame}[fragile]
+%%   \frametitle{Singular Value Decomposition}
+%%   \begin{small}
+%%   \begin{lstlisting}
+%% In []: svd(E)
+%% Out[]: 
+%% (array(
+%% [[ -6.66666667e-01,  -1.23702565e-16,   7.45355992e-01],
+%%  [ -3.33333333e-01,  -8.94427191e-01,  -2.98142397e-01],
+%%  [ -6.66666667e-01,   4.47213595e-01,  -5.96284794e-01]]),
+%%  array([ 8.,  1.,  1.]),
+%%  array([[-0.66666667, -0.33333333, -0.66666667],
+%%         [-0.        ,  0.89442719, -0.4472136 ],
+%%         [-0.74535599,  0.2981424 ,  0.59628479]]))
+%%   \end{lstlisting}
+%%   \end{small}
+%% \inctime{15}
+%% \end{frame}
 
 \section{Least Squares Fit}
 \begin{frame}[fragile]
-\frametitle{Least Squares Fit}
+\frametitle{$L$ vs. $T^2$}
 \vspace{-0.15in}
 \begin{figure}
-\includegraphics[width=4in]{data/L-Tsq-Line.png}
+\includegraphics[width=4in]{data/L-Tsq-points.png}
 \end{figure}
 \end{frame}
 
 \begin{frame}[fragile]
-\frametitle{Least Squares Fit}
+\frametitle{$L$ vs. $T^2$}
 \vspace{-0.15in}
 \begin{figure}
-\includegraphics[width=4in]{data/L-Tsq-points.png}
+\includegraphics[width=4in]{data/L-Tsq-Line.png}
 \end{figure}
 \end{frame}
 
@@ -383,7 +456,8 @@
 \item Along with a lot of things, it returns the least squares solution
 \end{itemize}
 \begin{lstlisting}
-In []: coef, res, r, s = lstsq(A,TSq)
+In []: result = lstsq(A,TSq)
+In []: coef = result[0]
 \end{lstlisting}
 \end{frame}