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Jan Grewe 2019-10-15 17:52:33 +02:00
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programming/exercises/variables_types.tex
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@ -1,4 +1,4 @@
\documentclass[12pt,a4paper,pdftex, answers]{exam}
\documentclass[12pt,a4paper,pdftex]{exam}
\usepackage[german]{babel}
\usepackage{natbib}

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programming/lecture/programming.tex
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@ -3,7 +3,7 @@
In this chapter we will cover the basics of programming in
\matlab{}. Starting with the concept of simple variables and data
types, we introduce basic data structures, such as vecotrs and
types, we introduce basic data structures, such as vectors and
matrices and show how one can work with them. Then we will address the
structures used to control the flow of the program and how to write
scripts and functions. Only a few of the concepts discussed in this
@ -14,13 +14,13 @@ simple.
\section{Variables and data types}
The ultimate goals of scientific computing is to analyze gathered
data, correlate it with e.g. stimulus conditions and infer rules and
The ultimate goal of scientific computing is to analyze gathered data,
correlate it with e.g. the stimulus conditions and infer rules and
dependencies. These may be used to constrain model that allow us to
understand and predict a system's behavior. In order to work with data
we need to store it somehow. For this purpose we use \emph{variables}
that allow us to store the data and give it a name for easy recognition
and to provide semantic meaning.
we need to store it somehow. For this purpose we use containers called
\emph{variables}. Variables store the data and are named for easier
recognition and to provide semantic meaning.
\subsection{Variables}
@ -89,6 +89,7 @@ information but it is not suited to be used in programs (see
also the \code{who} function that returns a list of all defined
variables, listing~\ref{varListing2}).
\newpage
\begin{lstlisting}[label=varListing2, caption={Requesting information about defined variables and their types.}]
>>class(x)
ans =
@ -115,6 +116,7 @@ x y z
variable names.
\end{important}
\pagebreak[4]
\subsection{Working with variables}
We can certainly work, i.e. do calculations, with variables. \matlab{}
knows all basic \codeterm[Operator!arithmetic]{arithmetic operators}
@ -125,7 +127,6 @@ such as \code[Operator!arithmetic!1add@+]{+},
\code[Operator!arithmetic!5pow@\^{}]{\^{}}. Listing~\ref{varListing3}
shows their use.
\pagebreak[4]
\begin{lstlisting}[label=varListing3, caption={Working with variables.}]
>> x = 1;
>> x + 10
@ -465,7 +466,7 @@ Error using +
Matrix dimensions must agree.
\end{lstlisting}
Element-wise multiplication and division to raise a vector to a given power requires a
Element-wise multiplication, division, or raising a vector to a given power requires a
different operator with a preceding '.'. \matlab{} defines the
following operators for element-wise operations on vectors
\code[Operator!arithmetic!3mule@.*]{.*},
@ -683,7 +684,7 @@ straight-forward or efficient solution to the problem. Consider for
example that you have a 3-D matrix and you want the minimal number in
that matrix. One could try to first find the minimum in each column,
then compare it to the elements on each page, and so on. An
alternative way is to make use of the so called \emph{linar indexing}
alternative way is to make use of the so called \emph{linear indexing}
in which each element of the matrix is addressed by a single
number. The linear index thus ranges from 1 to
\code{numel(matrix)}. The linear index increases first along the 1st,
@ -828,11 +829,11 @@ indexing, Section~\ref{logicalindexingsec}).
Truth tables (\ref{logicalandor}) are used to visualize the results of
Boolean expressions. A and B are statements that can be evaluated to
True or False. When they are combined with a logical AND the whole
expression is True only if both statements are True. The logical OR,
true or false. When they are combined with a logical AND the whole
expression is true only if both statements are true. The logical OR,
on the other hand, requires that at least one of the statements is
True. The exclusive OR (XOR) is True only for cases in which one of
the statements but not both are True. There is no operator for XOR in
true. The exclusive OR (XOR) is true only for cases in which one of
the statements but not both are true. There is no operator for XOR in
\matlab{} it is realized via the function \code[xor()]{xor(A, B)}.
\begin{table}[tp]
@ -860,7 +861,7 @@ the statements but not both are True. There is no operator for XOR in
\end{table}
Tables~\ref{logicalrelationaloperators} show the logical and
Table~\ref{logicalrelationaloperators} shows the logical and
relational operators available in \matlab{}. The additional
\code[Operator!logical!and2@\&\&]{\&\&} and
\code[Operator!logical!or2@{"|}{"|} {}]{||} operators are the so
@ -1360,11 +1361,11 @@ end
\begin{exercise}{simplerandomwalk.m}{}
Implement a 1-D random walk: Starting from the initial position $0$
the agent takes a step in a random direction.
the agent takes a step in a random direction with each iteration of the simulation.
\begin{itemize}
\item The program should do 10 random walks with 1000 steps each.
\item With each step decide randomly whether the position is changed
by $+1$ or $-1$.
\item Implement the random walk. With each step decide randomly whether the position is changed
by $+1$ or $-1$. The walk should have 1000 steps.
\item Extend the program to do 10 random walks with 1000 steps each.
\item Store all positions.
\item Create a figure in which you plot the position as a function
of the steps.
@ -1388,7 +1389,7 @@ and executed line-by-line from top to bottom.
Programs are stored in so called \codeterm{m-files}
(e.g. \file{myProgram.m}). To use them they have to be \emph{called}
from the command line of within another program. Storing your code in
from the command line or from within another program. Storing your code in
programs increases the re-usability. So far we have used
\emph{scripts} to store the solutions of the exercises. Any variable
that was created appeared in the \codeterm{workspace} and existed even