# HG changeset patch
# User Christian Urban <christian dot urban at kcl dot ac dot uk>
# Date 1478741445 0
# Node ID bb8c3dd8c75cd654747ff07818b604fd83534782
# Parent  fde9223a530109e8d3d143921320cf64354d877b# Parent  a81271342ff6c7f44281d3411eb12b775d068ddc
updated

diff -r fde9223a5301 -r bb8c3dd8c75c cws/cw01.pdf
diff -r fde9223a5301 -r bb8c3dd8c75c cws/cw01.tex
--- a/cws/cw01.tex	Thu Nov 10 01:30:15 2016 +0000
+++ b/cws/cw01.tex	Thu Nov 10 01:30:45 2016 +0000
@@ -83,7 +83,7 @@
 \item[(2)] Write a second function that takes an upper bound as
   argument and calculates the steps for all numbers in the range from
   1 up to this bound. It returns the maximum number of steps and the
-  corresponding number that needs that many steps.  More precisely
+  corresponding number that needs that many steps.  More precisely,
   it returns a pair where the first
   component is the number of steps and the second is the
   corresponding number. \hfill\mbox{[1 Mark]}
@@ -125,7 +125,7 @@
 to buy and when to sell this commodity. In the example above it should
 return the pair $\texttt{(1, 3)}$ because at index $1$ the price is lowest and
 then at index $3$ the price is highest. Note the prices are given as
-lists of \texttt{Float}s.\newline \mbox{} \hfill[1 Mark]
+lists of \texttt{Double}s.\newline \mbox{} \hfill[1 Mark]
 
 \item[(2)] Write a function that requests a comma-separated value (CSV) list
   from the Yahoo websevice that provides historical data for stock
@@ -186,13 +186,13 @@
 
 \subsection*{Advanced Part 3 (3 Marks)}
 
-A purely fictional character named Mr T.~Drump inherited in 1978
-approximately 200 Million Dollar from his father. Mr Drump prides
+A purely fictional character named Mr T.~Drumb inherited in 1978
+approximately 200 Million Dollar from his father. Mr Drumb prides
 himself to be a brilliant business man because nowadays it is
 estimated he is 3 Billion Dollar worth (one is not sure, of course,
-because Mr Drump refuses to make his tax records public).
+because Mr Drumb refuses to make his tax records public).
 
-Since the question about Mr Drump's business acumen remains, let's do a
+Since the question about Mr Drumb's business acumen remains open, let's do a
 quick back-of-the-envelope calculation in Scala whether his claim has
 any merit. Let's suppose we are given \$100 in 1978 and we follow a
 really dump investment strategy, namely:
@@ -215,7 +215,7 @@
 \end{itemize}\medskip  
 
 \noindent
-\textbf{Tasks (file drump.scala):}
+\textbf{Tasks (file drumb.scala):}
 
 \begin{itemize}
 \item[(1.a)] Write a function that queries the Yahoo financial data
@@ -313,7 +313,7 @@
 turn out to be a blue chip company.  Also, since the portfolios are
 chosen from the current S\&P 500, they do not include the myriad
 of companies that went bust or were de-listed over the years.
-So where does this leave our fictional character Mr T.~Drump? Well, given
+So where does this leave our fictional character Mr T.~Drumb? Well, given
 his inheritance, a really dumb investment strategy would have done
 equally well, if not much better.
 \end{document}
diff -r fde9223a5301 -r bb8c3dd8c75c progs/drumb.scala
--- a/progs/drumb.scala	Thu Nov 10 01:30:15 2016 +0000
+++ b/progs/drumb.scala	Thu Nov 10 01:30:45 2016 +0000
@@ -1,5 +1,5 @@
-// Advanvced Part 3 about Mr T. Drumb investing into stocks
-//==========================================================
+// Advanvced Part 3 about really dump investing strategy
+//=======================================================
 
 //two test portfolios
 
@@ -8,34 +8,55 @@
                             "DLR", "EQIX", "EQR", "ESS", "EXR", "FRT", "GGP", "HCP") 
 
 
-def get_yahoo_page(url: String): Option[List[String]] = ...
+// (1) The function below should obtain the first trading price
+// for a stock symbol by using the query
+//
+//    http://ichart.yahoo.com/table.csv?s=<<symbol>>&a=0&b=1&c=<<year>>&d=1&e=1&f=<<year>> 
+// 
+// and extracting the first January Adjusted Close price in a year.
 
 def get_first_price(symbol: String, year: Int): Option[Double] = ...
 
+// Complete the function below that obtains all first prices
+// for the stock symbols from a portfolio for the given
+// range of years
+
 def get_prices(portfolio: List[String], years: Range): List[List[Option[Double]]] = ...
 
+// test case
+//val p = get_prices(List("GOOG", "AAPL"), 2010 to 2012)
+
 
-//val p = get_prices(List("GOOG", "AAPL"), 2010 to 2012)
-
+// (2) The first function below calculates the change factor (delta) between
+// a price in year n and a price in year n+1. The second function calculates
+// all change factors for all prices (from a portfolio).
 
 def get_delta(price_old: Option[Double], price_new: Option[Double]): Option[Double] = ...
 
 def get_deltas(data: List[List[Option[Double]]]):  List[List[Option[Double]]] = ...
 
+// test case using the prices calculated above
 //val d = get_deltas(p)
 
 
+// (3) Write a function that given change factors, a starting balance and a year
+// calculates the yearly yield, i.e. new balanace, according to our dump investment 
+// strategy. Another function calculates given the same data calculates the
+// compound yield up to a given year. Finally a function combines all 
+// calculations by taking a portfolio, a range of years and a start balance
+// as arguments.
 
 def yearly_yield(data: List[List[Option[Double]]], balance: Long, year: Int): Long = ... 
 
+//test case
 //yearly_yield(d, 100, 0)
 
 def compound_yield(data: List[List[Option[Double]]], balance: Long, year: Int): Long = ... 
 
-
 def investment(portfolio: List[String], years: Range, start_balance: Long): Long = ...
 
 
+//test cases for the two portfolios given above
 //investment(rstate_portfolio, 1978 to 2016, 100)
 //investment(blchip_portfolio, 1978 to 2016, 100)
 
diff -r fde9223a5301 -r bb8c3dd8c75c progs/drumb_sol.scala
--- a/progs/drumb_sol.scala	Thu Nov 10 01:30:15 2016 +0000
+++ b/progs/drumb_sol.scala	Thu Nov 10 01:30:45 2016 +0000
@@ -1,5 +1,5 @@
-// Advanvced Part 3 about Mr T. Drumb investing into stocks
-//==========================================================
+// Advanvced Part 3 about really dump investing strategy
+//=======================================================
 
 //two test portfolios
 
@@ -7,6 +7,12 @@
 val rstate_portfolio = List("PLD", "PSA", "AMT", "AIV", "AVB", "BXP", "CBG", "CCI", 
                             "DLR", "EQIX", "EQR", "ESS", "EXR", "FRT", "GGP", "HCP") 
 
+// (1) The function below should obtain the first trading price
+// for a stock symbol by using the query
+//
+//    http://ichart.yahoo.com/table.csv?s=<<symbol>>&a=0&b=1&c=<<year>>&d=1&e=1&f=<<year>> 
+// 
+// and extracting the first January Adjusted Close price in a year.
 
 import io.Source
 import scala.util._
@@ -25,13 +31,24 @@
   data.map(_.last.split(",").toList(6).toDouble)
 }
 
+
+// Complete the function below that obtains all first prices
+// for the stock symbols from a portfolio for the given
+// range of years
+
 def get_prices(portfolio: List[String], years: Range): List[List[Option[Double]]] = 
   for (year <- years.toList) yield
     for (symbol <- portfolio) yield get_first_price(symbol, year)
 
-get_prices(List("GOOG", "AAPL"), 2010 to 2012)
+
+// test case
+//val p = get_prices(List("GOOG", "AAPL"), 2010 to 2012)
 
 
+// (2) The first function below calculates the change factor (delta) between
+// a price in year n and a price in year n+1. The second function calculates
+// all change factors for all prices (from a portfolio).
+
 def get_delta(price_old: Option[Double], price_new: Option[Double]): Option[Double] = {
   (price_old, price_new) match {
     case (Some(x), Some(y)) => Some((y - x) / x)
@@ -43,6 +60,19 @@
   for (i <- (0 until (data.length - 1)).toList) yield 
     for (j <- (0 until (data(0).length)).toList) yield get_delta(data(i)(j), data(i + 1)(j))
 
+
+// test case using the prices calculated above
+//val d = get_deltas(p)
+
+
+// (3) Write a function that given change factors, a starting balance and a year
+// calculates the yearly yield, i.e. new balanace, according to our dump investment 
+// strategy. Another function calculates given the same data calculates the
+// compound yield up to a given year. Finally a function combines all 
+// calculations by taking a portfolio, a range of years and a start balance
+// as arguments.
+
+
 def yearly_yield(data: List[List[Option[Double]]], balance: Long, year: Int): Long = {
   val somes = data(year).flatten
   val somes_length = somes.length
@@ -53,6 +83,9 @@
   }
 }
 
+//test case
+//yearly_yield(d, 100, 0)
+
 def compound_yield(data: List[List[Option[Double]]], balance: Long, year: Int): Long = {
   if (year >= data.length) balance else {
     val new_balance = yearly_yield(data, balance, year)
@@ -60,15 +93,13 @@
   }
 }
 
-val p = get_prices(List("GOOG", "AAPL"), 2010 to 2012)
-val d = get_deltas(p)
-yearly_yield(d, 100, 0)
-
 def investment(portfolio: List[String], years: Range, start_balance: Long): Long = {
   compound_yield(get_deltas(get_prices(portfolio, years)), start_balance, 0)
 }
 
 
+//test cases for the two portfolios given above
+
 println("Real data: " + investment(rstate_portfolio, 1978 to 2016, 100))
 println("Blue data: " + investment(blchip_portfolio, 1978 to 2016, 100))
 
diff -r fde9223a5301 -r bb8c3dd8c75c progs/lecture1.scala
--- a/progs/lecture1.scala	Thu Nov 10 01:30:15 2016 +0000
+++ b/progs/lecture1.scala	Thu Nov 10 01:30:45 2016 +0000
@@ -1,16 +1,16 @@
 // Lecture 1
-//==========
+//===========
 
-//**Assignments (values)**
-//(variable names should be lower case)
-//=====================================
+// Value assignments
+// (variable names should be lower case)
+//======================================
 
 val x = 42
 val y = 3 + 4
 
 
-//**Collections**
-//===============
+// Collections
+//=============
 List(1,2,3,1)
 Set(1,2,3,1)
 
@@ -26,13 +26,13 @@
 1::2::3::Nil
 List(1, 2, 3) ::: List(4, 5, 6)
 
-//**Printing/Strings**
-//====================
+// Printing/Strings
+//==================
 
 println("test")
 
 
-val tst = "This is a " + "test" 
+val tst = "This is a " ++ "test\n" 
 println(tst)
 
 val lst = List(1,2,3,1)
@@ -43,26 +43,39 @@
 // some methods take more than one argument
 println(lst.mkString("[", ",", "]"))
 
-//**Conversion methods**
-//======================
+// Conversion methods
+//====================
 
 List(1,2,3,1).toString
 List(1,2,3,1).toSet
 "hello".toList
 1.toDouble
 
-//**Types**
-//=========
+
+List(1,2,3,4).reverse
+
+// Types
+//=======
+
+/* Scala is a strongly typed language
+ 
+ * Base types
 
-// Int, Long, BigInt, Float, Double
-// String, Char
-// List[Int], Set[Double]
-// Pairs: (Int, String)        
-// List[(BigInt, String)]
+    Int, Long, BigInt, Float, Double
+    String, Char
+    Boolean
+
+ * Compound types 
 
+    List[Int],
+    Set[Double]
+    Pairs: (Int, String)        
+    List[(BigInt, String)]
+*/
 
-//**Smart Strings**
-//=================
+// Smart Strings
+//===============
+
 println(">\n<")
 println(""">\n<""")
 
@@ -81,8 +94,8 @@
 println(lyrics)
 
 
-//**Pairs/Tuples**
-//================
+// Pairs/Tuples
+//==============
 
 val p = (1, "one")
 p._1
@@ -91,52 +104,100 @@
 val t = (4,1,2,3)
 t._4
 
-//**Function Definitions**
-//========================
+// Hello World
+//=============
+
+// show an example of a stand-alone scala file
+// remind that in the course work you are asked a 
+// plain scala "work-sheet"
+
+
+
+// Function Definitions
+//======================
 
 def square(x: Int): Int = x * x
 
-
+square(6)
 
 
-//**Ifs control structures**
-//==========================
+// If control structure
+//======================
 
 def fact(n: Int): Int = 
   if (n == 0) 1 else n * fact(n - 1)
 
-
-
+/* boolean operators
+ 
+   ==     equals
+   !      not
+   && ||  and, or
+*/
 
 
 def fact2(n: BigInt): BigInt = 
   if (n == 0) 1 else n * fact2(n - 1)
 
+fact2(150)
+
+
 def fib(n: Int): Int =
   if (n == 0) 1 else
-    if (n == 1) 1 else fib(n - 1) + f(n - 2)
+    if (n == 1) 1 else fib(n - 1) + fib(n - 2)
+
+
+//gcd - Euclid's algorithm
+
+def gcd(a: Int, b: Int): Int =
+  if (b == 0) a else gcd(b, a % b)
+
+gcd(48, 18)
 
 
-//a recursive function
-def gcd(x: Int, y: Int): Int = 2 //??? 
+// String Interpolations
+//=======================
 
-//**String Interpolations**
-//=========================
+val n = 3
+println("The square of " + n + " is " + square(n) + ".")
+
+println(s"The square of ${n} is ${square(n)}.")
+
 
 
-//**Assert/Testing**
-====================
+def gcd_db(a: Int, b: Int): Int = {
+  println(s"Function called with ${a} and ${b}.")
+  if (b == 0) a else gcd_db(b, a % b)
+}
+
+gcd_db(48, 18)
 
-//**For-Maps (not For-Loops)**
-//============================
+
+// Assert/Testing
+//================
+
+// For-Comprehensions (not For-Loops)
+//====================================
 
 for (n <- (1 to 10).toList) yield square(n)
 
-for (n <- (1 to 10).toList; m <- (1 to 10).toList) yield m * n
+for (n <- (1 to 10).toList; 
+     m <- (1 to 10).toList) yield m * n
+
 
-val mtable = for (n <- (1 to 10).toList; m <- (1 to 10).toList) yield m * n
+val mult_table = 
+  for (n <- (1 to 10).toList; 
+       m <- (1 to 10).toList) yield m * n
 
-mtable.sliding(10,10).toList.mkString(
+mult_table.sliding(10,10).mkString("\n")
 
 
-// webpages
+// with patterns
+
+for ((m, n) <- List((1, 4), (2, 3), (3, 2), (4, 1))) yield m + n 
+
+for (p <- List((1, 4), (2, 3), (3, 2), (4, 1))) yield p._1 + p._2 
+
+
+
+// Webpages
+//==========
diff -r fde9223a5301 -r bb8c3dd8c75c slides/slides01.pdf
Binary file slides/slides01.pdf has changed
diff -r fde9223a5301 -r bb8c3dd8c75c slides/slides01.tex
--- a/slides/slides01.tex	Thu Nov 10 01:30:15 2016 +0000
+++ b/slides/slides01.tex	Thu Nov 10 01:30:45 2016 +0000
@@ -100,7 +100,8 @@
     \textcolor{codegreen}{\texttt{Float}},
     \textcolor{codegreen}{\texttt{Double}}\\
     \textcolor{codegreen}{\texttt{String}},
-    \textcolor{codegreen}{\texttt{Char}}
+    \textcolor{codegreen}{\texttt{Char}}\\
+    \textcolor{codegreen}{\texttt{Boolean}}
   \end{tabular}
   \end{center}
 
@@ -114,7 +115,7 @@
     \textcolor{codegreen}{\texttt{List[(BigInt, String)]}} &
                                       lists of BigInt-String\\
                                       & pairs\\
-    \textcolor{codegreen}{\texttt{List[List[Int]]}} \\                                  
+    \textcolor{codegreen}{\texttt{List[List[Int]]}} & list of lists of Int's\\                                  
   \end{tabular}
   \end{center}
 
diff -r fde9223a5301 -r bb8c3dd8c75c style.sty
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/style.sty	Thu Nov 10 01:30:45 2016 +0000
@@ -0,0 +1,23 @@
+\usepackage{xcolor}
+\usepackage[sc]{mathpazo}
+\usepackage{fontspec}
+\setmainfont[Ligatures=TeX]{Palatino Linotype}
+\usepackage{amssymb}
+\usepackage{amsmath}
+\usepackage{menukeys}
+\definecolor{darkblue}{rgb}{0,0,0.6}
+\usepackage[colorlinks=true,urlcolor=darkblue,linkcolor=darkblue]{hyperref}
+
+%%% for trees
+%% http://anorien.csc.warwick.ac.uk/mirrors/CTAN/graphics/pgf/contrib/forest/forest.pdf
+
+\newcommand{\dn}{\stackrel{\mbox{\scriptsize def}}{=}}
+\newcommand{\defn}[1]{\textit{\textbf{#1}}}
+\newcommand{\dq}[1]{\mbox{\tt{"}}#1\mbox{\tt{"}}}
+
+\definecolor{codegray}{gray}{0.9}
+
+\makeatletter
+\def\fnote{\gdef\@thefnmark{}\@footnotetext}
+\makeatother
+