//############################################################################
// Programmation IV - 2002 - Week 04
//############################################################################
// $Id$
object M0 {
def quicksort[a] (less : (a,a) => Boolean) (xs : List[a]) : List[a] = {
if (xs.isEmpty)
xs
else {
val pivot : a = xs.head;
val smaller : List[a] =
quicksort(less)(xs.tail.filter(elem => less(elem, pivot)));
val greaterOrEqual : List[a] =
quicksort(less)(xs.tail.filter(elem => !less(elem, pivot)));
smaller ::: List(pivot) ::: greaterOrEqual
}
}
def test = {
val isort: List[Int] => List[Int] = quicksort[Int]((x,y) => x < y);
val list0 = List(6,3,1,8,7,1,2,5,8,4,3,4,8);
val list1 = quicksort[Int]((x,y) => x < y)(list0);
val list2 = quicksort[Int]((x,y) => x < y)(list1);
val list3 = isort(list0);
val list4 = isort(list1);
val list5 = quicksort[Int]((x,y) => x >= y)(list0);
val list6 = quicksort[Int]((x,y) => x >= y)(list1);
Console.println("list0 = " + list0);
Console.println("list1 = " + list1);
Console.println("list2 = " + list2);
Console.println("list3 = " + list3);
Console.println("list4 = " + list4);
Console.println("list5 = " + list5);
Console.println("list6 = " + list6);
Console.println;
}
}
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object M1 {
def mergesort[a] (less : (a,a) => Boolean) (xs: Array[a]): Unit = {
def While(c: => Boolean)(b: => Unit): Unit =
if (c) { b ; While(c)(b) } else ();
def swap(i: Int, j: Int): Unit = {
val t = xs(i);
val u = xs(j);
xs(i) = u;
xs(j) = t;
}
def sort1(l: Int, r: Int): Unit = {
val pivot = xs((l + r) / 2);
var i = l;
var j = r;
While (i <= j) {
While (less(xs(i), pivot)) { i = i + 1 }
While (less(pivot, xs(j))) { j = j - 1 }
if (i <= j) {
swap(i, j);
i = i + 1;
j = j - 1;
}
}
if (l < j) sort1(l, j);
if (j < r) sort1(i, r);
}
if (xs.length > 0) sort1(0, xs.length - 1);
}
def list2array(list: List[Int]): Array[Int] = {
val array = new Array[Int](list.length);
list.copyToArray(array, 0);
array;
}
def array2list(array: Array[Int]): List[Int] = {
var list = List[Int]();
List.range(0, array.length).map(i => list = array(i) :: list);
list.reverse;
}
def isort(list: List[Int]): List[Int] = {
val array = list2array(list);
mergesort[Int]((x,y) => x < y)(array);
array2list(array);
}
def test = {
val list0 = List();
val list1 = List(0);
val list2 = List(0,1);
val list3 = List(1,0);
val list4 = List(0,1,2);
val list5 = List(1,0,2);
val list6 = List(0,1,2);
val list7 = List(1,0,2);
val list8 = List(2,0,1);
val list9 = List(2,1,0);
val listA = List(6,3,1,8,7,1,2,5,8,4);
Console.println("list0: " + list0 + " -> " + isort(list0));
Console.println("list1: " + list1 + " -> " + isort(list1));
Console.println("list2: " + list2 + " -> " + isort(list2));
Console.println("list3: " + list3 + " -> " + isort(list3));
Console.println("list4: " + list4 + " -> " + isort(list4));
Console.println("list5: " + list5 + " -> " + isort(list5));
Console.println("list6: " + list6 + " -> " + isort(list6));
Console.println("list7: " + list7 + " -> " + isort(list7));
Console.println("list8: " + list8 + " -> " + isort(list8));
Console.println("list9: " + list9 + " -> " + isort(list9));
Console.println("listA: " + listA + " -> " + isort(listA));
Console.println;
}
}
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object M2 {
def horner (x : Double, coefs : List[Double]) : Double = {
if (coefs.isEmpty)
0
else
horner(x, coefs.tail) * x + coefs.head
}
def test = {
val poly = List(9.0,5.0,7.0,5.0);
Console.println("f(x) = 5x^3+7x^2+5x+9");
Console.println("f(0) = " + horner(0, poly));
Console.println("f(1) = " + horner(1, poly));
Console.println("f(2) = " + horner(2, poly));
Console.println("f(3) = " + horner(3, poly));
Console.println;
}
}
//############################################################################
object M3 {
def dotproduct (v : List[Double], w : List[Double]) : Double = {
if (v.isEmpty)
0
else
(v.head * w.head) + dotproduct(v.tail, w.tail)
}
def matrixTimesVector (m : List[List[Double]], v : List[Double])
: List[Double] = {
m.map(row => dotproduct(row, v))
}
def transpose(m : List[List[Double]]) : List[List[Double]] = {
if (m.isEmpty || m.head.isEmpty)
List()
else
m.map(row => row.head) :: transpose (m.map (row => row.tail))
}
def matrixTimesMatrix(m1 : List[List[Double]], m2 : List[List[Double]])
: List[List[Double]] = {
val columns = transpose(m2);
m1.map(row => matrixTimesVector(columns, row))
}
def test = {
val v1 = List(2.0,3.0,4.0);
val v2 = List(6.0,7.0,8.0);
def id = List(List(1.0,0.0,0.0),List(0.0,1.0,0.0),List(0.0,0.0,1.0));
def m1 = List(List(2.0,0.0,0.0),List(0.0,2.0,0.0),List(0.0,0.0,2.0));
def m2 = List(List(1.0,2.0,3.0),List(4.0,5.0,6.0),List(7.0,8.0,9.0));
def v = List(2.0,3.0,4.0);
Console.println("v1 = " + v1);
Console.println("v2 = " + v2);
Console.println;
Console.println("id = " + id);
Console.println("m1 = " + m1);
Console.println("m2 = " + m2);
Console.println;
Console.println("v1 * v1 = " + dotproduct(v1,v1));
Console.println("v1 * v2 = " + dotproduct(v1,v2));
Console.println("v2 * v1 = " + dotproduct(v2,v1));
Console.println("v1 * v2 = " + dotproduct(v1,v2));
Console.println;
Console.println("id * v1 = " + matrixTimesVector(id,v1));
Console.println("m1 * v1 = " + matrixTimesVector(m1,v1));
Console.println("m2 * v1 = " + matrixTimesVector(m2,v1));
Console.println;
Console.println("trn(id) = " + transpose(id));
Console.println("trn(m1) = " + transpose(m1));
Console.println("trn(m2) = " + transpose(m2));
Console.println;
Console.println("List(v1) * id = " + matrixTimesMatrix(List(v1),id));
Console.println("List(v1) * m1 = " + matrixTimesMatrix(List(v1),m1));
Console.println("List(v1) * m2 = " + matrixTimesMatrix(List(v1),m2));
Console.println;
Console.println("id * List(v1) = " + matrixTimesMatrix(id,List(v1)));
Console.println("m1 * List(v1) = " + matrixTimesMatrix(m1,List(v1)));
Console.println("m2 * List(v1) = " + matrixTimesMatrix(m2,List(v1)));
Console.println;
Console.println("id * id = " + matrixTimesMatrix(id,id));
Console.println("id * m1 = " + matrixTimesMatrix(id,m1));
Console.println("m1 * id = " + matrixTimesMatrix(m1,id));
Console.println("m1 * m1 = " + matrixTimesMatrix(m1,m1));
Console.println("id * m2 = " + matrixTimesMatrix(id,m2));
Console.println("m2 * id = " + matrixTimesMatrix(m2,id));
Console.println("m1 * m2 = " + matrixTimesMatrix(m1,m2));
Console.println("m2 * m1 = " + matrixTimesMatrix(m2,m1));
Console.println("m2 * m2 = " + matrixTimesMatrix(m2,m2));
Console.println;
}
}
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object Test {
def main(args: Array[String]): Unit = {
M0.test;
M1.test;
M2.test;
M3.test;
()
}
}
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