teaching/scientificComputing
Archived
3
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

[programming] language fixes in chapter and exercises

Browse Source
This commit is contained in:
Jan Grewe 2019-10-25 13:10:34 +02:00
parent 55b3451152
commit a518043a02
3 changed files with 23 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
programming/exercises/matrices.tex
View File

@ -54,7 +54,7 @@ following pattern:
\begin{solution}
\code{x = [7 3 5; 1 8 3; 8 6 4];\\disp(size(x))}
\end{solution}
\part Use the help to figure out how to get only the size along a certain axis. Print the sizes of each dimension.
\part Use the help to figure out how to get only the size along a certain dimension. Display the sizes of each dimension.
\begin{solution}
\code{disp(size(x, 1))}\\\code{disp(size(x, 2))}
\end{solution}
@ -94,12 +94,12 @@ following pattern:
\code{disp(M(2,3))}
\end{solution}
\part Print all elements of the 1st, 3rd and last line.
\part Display all elements of the 1st, 3rd and last line.
\begin{solution}
\code{disp(M(1,:)) \\ disp(M(3,:))\\ disp(M(size(M,1), :))}
\end{solution}
\part Print the elements of the 2nd and 4th column.
\part Display the elements of the 2nd and 4th column.
\begin{solution}
\code{disp(M(:,2))\\ disp(M(:,4))}
\end{solution}
@ -109,7 +109,7 @@ following pattern:
\code{y = M(:, [2:2:size(M,2)])}
\end{solution}
\part Calculate the averages of lines 1, 3, and 5 (use the function mean, see help).
\part Calculate the averages of lines 1, 3, and 5 (use the function \verb+mean+}, see help).
\begin{solution}
\code{mean(M([1 3 5],:), 2)}
\end{solution}
@ -141,9 +141,9 @@ following pattern:
\end{parts}
\question Indexing in matrices can use the
\textit{subscript} indices or the \textit{linear} indices (you may want to check the help for the \verb+sub2ind+ and \verb+ind2sub+).
\textit{subscript} indices or the \textit{linear} indices (you may want to check the help for the functions \verb+sub2ind+ and \verb+ind2sub+).
\begin{parts}
\part Create a 2-D matric filled with random numbers and the dimensionality
\part Create a 2-D matrix filled with random numbers and the size
\verb+[10,10]+.
\begin{solution}
\code{x = randn(10, 10)}
@ -154,12 +154,12 @@ following pattern:
\code{disp(numel(x))}
\end{solution}
\part Employ linar indexing to select 50 random values.
\part Employ linear indexing to select 50 random values.
\begin{solution}
\code{x(randi(100, 50, 1)])}
\end{solution}
\part Can you imaging an advantage of using linear indexing instead of subscript indexing?
\part Can you imagine an advantage of using linear indexing instead of subscript indexing?
\begin{solution}
Die Matrize ist 2-dimensional. Wenn mit dem subscript index
zugegriffen werden soll, dann muss auf die Dimensionen
@ -225,7 +225,7 @@ following pattern:
\begin{parts}
\part Calculate the average of each ``page'' (function \verb+mean()+, see help).
\begin{solution}
\code{x = round(rand(5,5,5) .* 100);\\ Disp(mean(mean(x(:,:,1))))\\ disp(mean(mean(x(:,:,2)))) \\ disp(mean(mean(x(:,:,3))))}
\code{x = round(rand(5,5,5) .* 100);\\ disp(mean(mean(x(:,:,1))))\\ disp(mean(mean(x(:,:,2)))) \\ disp(mean(mean(x(:,:,3))))}
\end{solution}
\end{parts}
\end{questions}

20
programming/exercises/vectors.tex
View File

@ -95,7 +95,7 @@ following pattern: ``variables\_datatypes\_\{lastname\}.m''
\code{disp(x * 2)}
\end{solution}
\part Create a second vector (\verb+y = [4 1 3 5];+).
Make sure that \code{x} is in its original form.
Make sure that \code{x} is in its original form (see (a)).
\part Add both vectors \code{x + y}.
\begin{solution}
\code{y = [4 1 3 5]; \\disp(x + y)\\7 3 9 13}
@ -155,23 +155,23 @@ following pattern: ``variables\_datatypes\_\{lastname\}.m''
\question Indexing in vectors:
\begin{parts}
\part Create a 100 element length vector with values ranging from 0 to 99.
\part Create a vector of the length 100 with values ranging from 0 to 99.
\begin{solution}
\code{x = linspace(0, 99, 100);}
\end{solution}
\part Print the first, last, fifth, 24th and the second-to-last value.
\part use \code{disp()) to display the first, last, fifth, 24th and the second-to-last value on the command line.
\begin{solution}
\code{disp(x(1))\\ disp(x(end))\\ disp(x(5))\\ disp(x(24))\\ disp(x(end-1))}
\end{solution}
\part Print the first 10 values.
\part Display the first 10 values.
\begin{solution}
\code{x(1:10)}
\end{solution}
\part Print the last 10 values.
\part Display the last 10 values.
\begin{solution}
\code{disp(x(end-9:end))}
\end{solution}
\part Try to print the value at the zeroth position.
\part Try to display the value at the zeroth position.
\begin{solution}
\code{x(0)\\ Subscript indices must either be real positive integers or logicals.}
\end{solution}
@ -179,18 +179,18 @@ following pattern: ``variables\_datatypes\_\{lastname\}.m''
\begin{solution}
\code{x(110)\\ Index exceeds matrix dimensions.}
\end{solution}
\part Access the values at the positions 3, 15, and 42 with a single command.
\part Access and display the values at the positions 3, 15, and 42 with a single command.
\begin{solution}
\code{disp(x([3 15 42]))}
\end{solution}
\part Access 10 randomly selected values (used \verb+randi+ to create random indices).
\part Access and display 10 randomly selected values (used \verb+randi+ to create random indices).
\begin{solution}
\code{x(randi(100, 10, 1))}
\code{disp(x(randi(100, 10, 1)))}
\end{solution}
\end{parts}
\question Store some text in a variable. The text should consist of at least two words (e.g. \code{x = 'some
text'}). Use indexing to print out the words individually.
text'}). Use indexing to display the words individually.
\begin{solution}
\code{x = 'some text'; \\ disp(x(1:4))\\disp(x(6:end))}
\end{solution}

8
programming/lecture/programming.tex
View File

@ -254,7 +254,7 @@ type (figure~\ref{vectorfig} B). The variable \varcode{test} in
\begin{figure}[ht]
\includegraphics[width=0.8\columnwidth]{scalarArray}
\titlecaption{Scalars and vectors.}{\textbf{A)} A scalar variable
holds exactly on value. \textbf{B)} A vector can hold multiple
holds exactly one value. \textbf{B)} A vector can hold multiple
values. These must be of the same data type (e.g. integer
numbers). \matlab{} distinguishes between row- and
column-vectors.}\label{vectorfig}
@ -646,7 +646,7 @@ and should be always preferred over \code{length()}.
Analogous to the data access in vectors we can address individual
elements of a matrix by it's index. Similar to a coordinate system
each element is addressed using a n-tuple with $n$ the number of
each element is addressed using an n-tuple with $n$ the number of
dimensions (figure~\ref{matrixindexingfig},
listing~\ref{matrixIndexing}). This type of indexing is called
\codeterm{subscript indexing}. The first coordinate refers always to
@ -910,10 +910,10 @@ this can save processing time.
Previously we have introduced the data types for integer or floating
point numbers and discussed that there are instances in which it is
more efficient to use a integer data type rather than storing floating
more efficient to use an integer data type rather than storing floating
point numbers. The result of a Boolean expression can only assume two
values (true or false). This implies that we need only a single bit to
store this information as a 0 (false) and 1 (true). \matlab{} knows a
store this information as 0 (false) or 1 (true). \matlab{} knows a
special data type (\codeterm{logical}) to store the result of a
Boolean expression. Every variable can be evaluated to true or false
by converting it to the logical data type. When doing so \matlab{}