From 86ba1bc0fe7a0c921f5db41b57522cd6d174299c Mon Sep 17 00:00:00 2001
From: Jan Benda <jan.benda@uni-tuebingen.de>
Date: Tue, 22 Nov 2016 09:26:50 +0100
Subject: [PATCH] fakultaet is factorial!

---
 programming/exercises/faculty.m             |  8 --------
 programming/exercises/facultyscripta.m      |  6 ------
 programming/exercises/facultyscriptb.m      |  1 -
 programming/exercises/facultyscriptc.m      |  3 ---
 programming/exercises/myfactorial.m         |  7 +++++++
 programming/exercises/plotsine.m            |  4 ++--
 programming/exercises/plotsineb.m           |  2 +-
 programming/exercises/plotsinec.m           |  2 +-
 programming/exercises/plotsined.m           |  2 +-
 programming/exercises/printfaculty.m        |  8 --------
 programming/exercises/randomwalkthresh.m    |  7 +++----
 programming/exercises/scripts_functions.tex | 10 +++++-----
 programming/exercises/sinewave.m            |  4 ++--
 13 files changed, 22 insertions(+), 42 deletions(-)
 delete mode 100644 programming/exercises/faculty.m
 delete mode 100644 programming/exercises/facultyscripta.m
 delete mode 100644 programming/exercises/facultyscriptb.m
 delete mode 100644 programming/exercises/facultyscriptc.m
 create mode 100644 programming/exercises/myfactorial.m
 delete mode 100644 programming/exercises/printfaculty.m

diff --git a/programming/exercises/faculty.m b/programming/exercises/faculty.m
deleted file mode 100644
index 41992ac..0000000
--- a/programming/exercises/faculty.m
+++ /dev/null
@@ -1,8 +0,0 @@
-function x = faculty(n)
-% return the faculty of n
-x = 1;
-for i = 1:n
-    x = x * i;
-end
-% x = prod(1:n)  % this is a one line alternative to the for loop!
-end
\ No newline at end of file
diff --git a/programming/exercises/facultyscripta.m b/programming/exercises/facultyscripta.m
deleted file mode 100644
index be0ed55..0000000
--- a/programming/exercises/facultyscripta.m
+++ /dev/null
@@ -1,6 +0,0 @@
-n = 5;
-x = 1;
-for i = 1:n
-    x = x * i;
-end 
-fprintf('Faculty of %i is: %i\n', n, x)
diff --git a/programming/exercises/facultyscriptb.m b/programming/exercises/facultyscriptb.m
deleted file mode 100644
index 8488431..0000000
--- a/programming/exercises/facultyscriptb.m
+++ /dev/null
@@ -1 +0,0 @@
-printfaculty(5);
diff --git a/programming/exercises/facultyscriptc.m b/programming/exercises/facultyscriptc.m
deleted file mode 100644
index 0804287..0000000
--- a/programming/exercises/facultyscriptc.m
+++ /dev/null
@@ -1,3 +0,0 @@
-n = 5
-a = faculty(n);
-fprintf('Faculty of %i is: %i\n', n, x)
diff --git a/programming/exercises/myfactorial.m b/programming/exercises/myfactorial.m
new file mode 100644
index 0000000..2c5668c
--- /dev/null
+++ b/programming/exercises/myfactorial.m
@@ -0,0 +1,7 @@
+function x = mufactorial(n)
+% return the factorial of n
+x = 1;
+for i = 1:n
+    x = x * i;
+end
+end
diff --git a/programming/exercises/plotsine.m b/programming/exercises/plotsine.m
index 18f562e..8828b17 100644
--- a/programming/exercises/plotsine.m
+++ b/programming/exercises/plotsine.m
@@ -1,9 +1,9 @@
-function plotsine(freq, ampl, duration, step)
+function plotsine(freq, ampl, duration)
 % plot a sine wave
 % freq: frequency of the sinewave in Hertz
 % ampl: amplitude of the sinewave
 % duration: duration of the sinewave in seconds
-% step: stepsize for plotting in seconds
+step = 0.01/freq;
 time = 0:step:duration;
 sine = ampl*sin(2*pi*freq*time);
 if duration <= 1.0
diff --git a/programming/exercises/plotsineb.m b/programming/exercises/plotsineb.m
index b7cb2b8..48690d4 100644
--- a/programming/exercises/plotsineb.m
+++ b/programming/exercises/plotsineb.m
@@ -1 +1 @@
-plotsine(5.0, 2.0, 1.5, 0.001)
+plotsine(5.0, 2.0, 1.5)
diff --git a/programming/exercises/plotsinec.m b/programming/exercises/plotsinec.m
index 6e4bd8c..2b077a7 100644
--- a/programming/exercises/plotsinec.m
+++ b/programming/exercises/plotsinec.m
@@ -1,6 +1,6 @@
 freq = 5.0;
 ampl = 2.0;
-[time, sine] = sinewave(freq, ampl, 1.5, 0.001);
+[time, sine] = sinewave(freq, ampl, 1.5);
 
 if duration <= 1.0
 	plot(1000.0*time, sine);
diff --git a/programming/exercises/plotsined.m b/programming/exercises/plotsined.m
index d6bf5d8..42cf19d 100644
--- a/programming/exercises/plotsined.m
+++ b/programming/exercises/plotsined.m
@@ -1,4 +1,4 @@
 freq = 5.0;
 ampl = 2.0;
-[time, sine] = sinewave(freq, ampl, 1.5, 0.001);
+[time, sine] = sinewave(freq, ampl, 1.5);
 plotsinewave(time, sine);
diff --git a/programming/exercises/printfaculty.m b/programming/exercises/printfaculty.m
deleted file mode 100644
index bb3fa1f..0000000
--- a/programming/exercises/printfaculty.m
+++ /dev/null
@@ -1,8 +0,0 @@
-function printfaculty(n)
-% compute the faculty of n and print it
-x = 1;
-for i = 1:n
-    x = x * i;
-end 
-fprintf('Faculty of %i is: %i\n', n, x)
-end
\ No newline at end of file
diff --git a/programming/exercises/randomwalkthresh.m b/programming/exercises/randomwalkthresh.m
index 15af9e5..731c425 100644
--- a/programming/exercises/randomwalkthresh.m
+++ b/programming/exercises/randomwalkthresh.m
@@ -9,17 +9,16 @@ function positions = randomwalkthresh(p, thresh)
 % positions: vector with positions of the random walker
 
 positions = [0.0];
+% positions = 0.0;
+% positions = zeros(1, 1);
 i = 2;
-while true
+while abs(positions(i-1)) < thresh
 	r = rand(1);
 	if r < p
 		positions(i) = positions(i-1) + 1;
 	else
 		positions(i) = positions(i-1) - 1;
 	end
-	if abs(positions(i)) > thresh
-		break
-	end
 	i = i + 1;
 end
 end
diff --git a/programming/exercises/scripts_functions.tex b/programming/exercises/scripts_functions.tex
index 22975d3..1167437 100644
--- a/programming/exercises/scripts_functions.tex
+++ b/programming/exercises/scripts_functions.tex
@@ -73,20 +73,20 @@ also als zip-Archiv auf ILIAS hochladen. Das Archiv sollte nach dem Muster:
     \part Version 1: berechnet die Fakult\"at von 5 und gib das
     Resultat auf dem Bildschirm aus.
     \begin{solution}
-      \lstinputlisting{facultyscripta.m}
+      \lstinputlisting{factorialscripta.m}
     \end{solution}
 
     \part Version 2: Wie 1 aber die Funktion \"ubernimmt als Argument
     die Zahl, von der die Fakult\"at berechnet werden soll.
     \begin{solution}
-      \lstinputlisting{printfaculty.m}
-      \lstinputlisting{facultyscriptb.m}
+      \lstinputlisting{printfactorial.m}
+      \lstinputlisting{factorialscriptb.m}
     \end{solution}
 
     \part Version 3: Wie 2 aber mit R\"uckgabe des berechneten Wertes.
     \begin{solution}
-      \lstinputlisting{faculty.m}
-      \lstinputlisting{facultyscriptc.m}
+      \lstinputlisting{myfactorial.m}
+      \lstinputlisting{factorialscriptc.m}
     \end{solution}
 
   \end{parts}
diff --git a/programming/exercises/sinewave.m b/programming/exercises/sinewave.m
index 42f9362..5e446b9 100644
--- a/programming/exercises/sinewave.m
+++ b/programming/exercises/sinewave.m
@@ -1,12 +1,12 @@
-function [time, sine] = sinewave(freq, ampl, duration, step)
+function [time, sine] = sinewave(freq, ampl, duration)
 % compute sine wave with time axis
 % freq: frequency of the sinewave in Hertz
 % ampl: amplitude of the sinewave
 % duration: duration of the sinewave in seconds
-% step: stepsize for plotting in seconds
 % returns:
 % time: vector of time points
 % sine: corresponding vector with the sine wave
+step = 0.01/freq;
 time = 0:step:duration;
 sine = ampl*sin(2*pi*freq*time);
 end