38 \title[Basic Python]{Python: Quiz}

    38 \title[Basic Python]{Python for science and engineering: Day 1, Quiz 2}

    43 \date[] {11, October 2009\\Day 2}

    43 \date[] {\today \\

    44 Day 1, quiz 2}

    57     \item  Name:

    58     \item Name:

    58     \item Affliation:

    59     \item University/College/Company:

    59     \item Occupation:

    60     \item Student/Teacher/Professional:

    63 \begin{frame}[fragile]

    64 %% \begin{frame}[fragile]

    64 \frametitle{\incqno }

    65 %% \frametitle{\incqno }

    65 \begin{lstlisting}

    66 %% \begin{lstlisting}

    66   >>> x = array([[1,2,3,4],[3,4,2,5]])

    67 %%   In []: x = array([[1,2,3,4],

    67   >>> x.shape

    68 %%                     [3,4,2,5]])

    68   (2, 4)

    69 %% \end{lstlisting}

    69 \end{lstlisting}

    70 %% What is the \lstinline+shape+ of this array?

    70 Change the shape of \lstinline+x+ to (4,2)

    71 %% \end{frame}

    71 \end{frame}

    72 

    72 

    73 

    73 \begin{frame}[fragile]

    74 \begin{frame}[fragile]

    74 \frametitle{\incqno }

    75 \frametitle{\incqno }

    75 \begin{lstlisting}

    76 \begin{lstlisting}

    76   >>> x = array([[1,2,3,4]])

    77   In []: x = array([[1,2,3,4]])

    77 \end{lstlisting}

    78 \end{lstlisting}

    78 How to change the third element of \lstinline+x+ to 0?

    79 How to change the third element (i.e.\ 3) of \lstinline+x+ to 0?

    79 \end{frame}

    80 \end{frame}

    80 

    81 

    81 \begin{frame}[fragile]

    82 \begin{frame}[fragile]

    82 \frametitle{\incqno }

    83 \frametitle{\incqno }

    83 What would be the result?

    84 \begin{lstlisting}

    84 \begin{lstlisting}

    85   In []: x = array([[1,2,3,4],

    85   >>> y = arange(3)

    86                     [3,4,2,5]])

    86   >>> x = linspace(0,3,3)

    87 \end{lstlisting}

    87   >>> x-y

    88 How do you get the following slice of \lstinline+x+?

    88 \end{lstlisting}

    89 \begin{lstlisting}

    89 \end{frame}

    90 array([[2,3],

    90 

    91        [4,2]])

    91 \begin{frame}[fragile]

    92 \end{lstlisting}

    92 \frametitle{\incqno }

    93 \end{frame}

    93 \begin{lstlisting}

    94 

    94   >>> x = array([0, 1, 2, 3])

    95 

    95   >>> x.shape = 2,2

    96 %% \begin{frame}

    96   >>> x

    97 %% \frametitle{\incqno }

    97   array([[0, 1],

    98 %% The file \lstinline+datafile.txt+ contains 3 columns of data.  What

    98          [2, 3]])

    99 %% command will you use to read the entire data file into an array?

    99   >>> x[::2,::2]

   100 %% \end{frame}

   100 \end{lstlisting}

   101 

   101 What is the output?

   102 %% \begin{frame}

   102 \end{frame}

   103 %% \frametitle{\incqno }

   103 

   104 

   104 \begin{frame}[fragile]

   105 %% If the contents of the file \lstinline+datafile.txt+ is read into an

   105 \frametitle{\incqno }

   106 %% $N\times3$ array called \lstinline+data+, how would you obtain the third

   106 What would be the result?

   107 %% column of this data?

   107 \begin{lstlisting}

   108 

   108   >>> x

   109 %% \end{frame}

   109   array([[0, 1, 2],

   110 

   110          [3, 4, 5],

   111 \begin{frame}[fragile]

   111          [6, 7, 8]])

   112 \frametitle{\incqno }

   112   >>> x[::-1,:]

   113 \begin{lstlisting}

   113 \end{lstlisting}

   114   In []: x = array(([1,2,3,4],

   114 Hint:

   115                     [2,3,4,5]))

   115 \begin{lstlisting}

   116   In []: x[-2][-3] = 4

   116   >>> x = arange(9)

   117   In []: print x

   117   >>> x[::-1]

   118   array([8, 7, 6, 5, 4, 3, 2, 1, 0])

   119 \end{lstlisting}

   120 \end{frame}

   121 

   122 \begin{frame}[fragile]

   123 \frametitle{\incqno }

   124 \begin{lstlisting}

   125   >>> x

   126   array([[ 0, 1, 2, 3],

   127          [ 4, 5, 6, 7],

   128          [ 8, 9, 10, 11],

   129          [12, 13, 14, 15]])

   130 \end{lstlisting}

   131 How will you get the following \lstinline+x+?

   132 \begin{lstlisting}

   133   array([[ 5, 7],

   134          [ 9, 11]])

   135 \end{lstlisting}

   136 \end{frame}

   137 

   138 \begin{frame}[fragile]

   139 \frametitle{\incqno }

   140 \begin{lstlisting}

   141   >>> x = array(([1,2,3,4],[2,3,4,5]))

   142   >>> x[-2][-3] = 4

   143   >>> x

   148 \begin{frame}[fragile]

   122 

   149 \frametitle{\incqno }

   123 %% \begin{frame}[fragile]

   150 What would be the output?

   124 %% \frametitle{\incqno }

   151 \begin{lstlisting}

   125 %% \begin{lstlisting}

   152   >>> y = arange(4)

   126 %%   In []: x = arange(0, 1, 0.25)

   153   >>> x = array(([1,2,3,2],[1,3,6,0]))

   127 %%   In []: print x

   154   >>> x + y

   128 %% \end{lstlisting}

   155 \end{lstlisting}

   129 %% What will be printed?

   156 \end{frame}

   130 %% \end{frame}

   157 

   131 

   158 \begin{frame}[fragile]

   132 

   159 \frametitle{\incqno }

   133 %% \begin{frame}[fragile]

   160 \begin{lstlisting}

   134 %% \frametitle{\incqno }

   161   >>> line = plot(x, sin(x))

   135 %% \begin{lstlisting}

   162 \end{lstlisting}

   136 %% from scipy.integrate import quad

   163 Use the \lstinline+set_linewidth+ method to set width of \lstinline+line+ to 2.

   137 %% def f(x):

   164 \end{frame}

   138 %%     res = x*cos(x)

   165 

   139 

   166 \begin{frame}[fragile]

   140 %% quad(f, 0, 1)

   167 \frametitle{\incqno }

   141 %% \end{lstlisting}

   168 What would be the output?

   142 

   169 \begin{lstlisting}

   143 %% What changes will you make to the above code to make it work?

   170   >>> x = arange(9)

   144 %% \end{frame}

   171   >>> y = arange(9.)

   145 

   172   >>> x == y

   146 %% \begin{frame}

   173 \end{lstlisting}

   147 %% \frametitle{\incqno }

   174 \end{frame}

   148 %% What two commands will you use to create and evaluate a spline given

   175 

   149 %% some data?

   150 %% \end{frame}

   151 

   152 \begin{frame}

   153 \frametitle{\incqno }

   154 What command will you use if you wish to integrate a system of ODEs?

   155 \end{frame}

   156 

   157 \begin{frame}

   158 \frametitle{\incqno }

   159 How do you calculate the roots of the polynomial, $y = 1 + 6x + 8x^2 +

   160 x^3$?

   161 \end{frame}

   162 

   163 \begin{frame}

   164 \frametitle{\incqno }

   165 

   166 Two arrays \lstinline+a+ and \lstinline+b+ are numerically almost equal, what command

   167 do you use to check if this is true?

   168 

   169 \end{frame}

   170 

   171 \begin{frame}[fragile]

   172 \frametitle{\incqno }

   173 \begin{lstlisting}

   174 In []: marks = [10, 20, 30, 50, 55, 

   175                75, 83] 

   176 \end{lstlisting}

   177 How will you convert the list \texttt{marks} to an \alert{array}?

   178 \end{frame}

   179 

   180 \begin{frame}[fragile]

   181 \frametitle{\incqno }

   182 \begin{lstlisting}

   183 In []: a = array([[1, 2],

   184                   [3, 4]])

   185 In []: a[1,0] = 0

   186 \end{lstlisting}

   187 What is the resulting matrix?

   188 \end{frame}

   189 

   190 \begin{frame}[fragile]

   191 \frametitle{\incqno }

   192 \begin{lstlisting}

   193 In []: a = array([[1, 2],

   194                   [3, 4]])

   195 \end{lstlisting}

   196 How do you get the transpose of this array?

   197 \end{frame}

   198 

   199 \begin{frame}[fragile]

   200 \frametitle{\incqno }

   201 \begin{lstlisting}

   202 In []: a = array([[1, 2],

   203                   [3, 4]])

   204 In []: b = array([[1, 1],

   205                   [2, 2]])

   206 In []: a*b

   207 \end{lstlisting}

   208 What does this produce?

   209 \end{frame}

   210 

   211 \begin{frame}

   212 \frametitle{\incqno }

   213 What command do you use to find the inverse of a matrix and its

   214 eigenvalues?

   215 \end{frame}

   216 

   217 \begin{frame}

   218 \frametitle{\incqno }

   219 Given a 4x4 matrix \texttt{A} and a 4-vector \texttt{b}, what command do

   220 you use to solve for the equation \\

   221 \texttt{Ax = b}?

   222 \end{frame}