Another update from ingydotnet^djgoku

Task/Identity-matrix/APL/identity-matrix-1.apl

@@ -1,4 +1,4 @@
-    ∘.=/⍳¨3 3
+    ∘.=⍨⍳3
 1 0 0
 0 1 0
 0 0 1

Task/Identity-matrix/APL/identity-matrix-2.apl

@@ -1,4 +1,4 @@
-    ID←{∘.=/⍳¨ ⍵ ⍵}
+    ID←{∘.=⍨⍳⍵}
     ID 5
 1 0 0 0 0
 0 1 0 0 0

Task/Identity-matrix/Applesoft-BASIC/identity-matrix.applesoft

@@ -0,0 +1,15 @@
+100 INPUT "MATRIX SIZE:"; SIZE%
+110 GOSUB 200"IDENTITYMATRIX
+120 FOR R = 0 TO SIZE%
+130     FOR C = 0 TO SIZE%
+140         LET S$ = CHR$(13)
+150         IF C < SIZE% THEN S$ = " "
+160         PRINT IM(R, C) S$; : NEXT C, R
+170 END
+
+200 REMIDENTITYMATRIX SIZE%
+210 LET SIZE% = SIZE% - 1
+220 DIM IM(SIZE%, SIZE%)
+230 FOR I = 0 TO SIZE%
+240     LET IM(I, I) = 1 : NEXT I
+250 RETURN :IM

Task/Identity-matrix/Delphi/identity-matrix.delphi

@@ -0,0 +1,25 @@
+program IdentityMatrix;
+
+// Modified from the Pascal version
+
+{$APPTYPE CONSOLE}
+
+var
+  matrix: array of array of integer;
+  n, i, j: integer;
+
+begin
+  write('Size of matrix: ');
+  readln(n);
+  setlength(matrix, n, n);
+
+  for i := 0 to n - 1 do
+    matrix[i,i] := 1;
+
+  for i := 0 to n - 1 do
+  begin
+    for j := 0 to n - 1 do
+      write (matrix[i,j], ' ');
+    writeln;
+  end;
+end.

Task/Identity-matrix/Elixir/identity-matrix.elixir

@@ -0,0 +1,9 @@
+defmodule Matrix do
+  def identity(n) do
+    Enum.map(0..n-1, fn i ->
+      for j <- 0..n-1, do: (if i==j, do: 1, else: 0)
+    end)
+  end
+end
+
+IO.inspect Matrix.identity(5)

Task/Identity-matrix/Fortran/identity-matrix-2.f

@@ -0,0 +1,9 @@
+      Program Identity
+      Integer N
+      Parameter (N = 666)
+      Real A(N,N)
+      Integer i,j
+
+      ForAll(i = 1:N, j = 1:N) A(i,j) = (i/j)*(j/i)
+
+      END

Task/Identity-matrix/Go/identity-matrix-1.go

@@ -1,18 +1,19 @@
 package main
 
-import "fmt"
+import (
+    "fmt"
 
-func main() {
-    fmt.Println(I(3))
-}
+    "github.com/gonum/matrix/mat64"
+)
 
-func I(n int) [][]float64 {
-    m := make([][]float64, n)
-    a := make([]float64, n*n)
+func eye(n int) *mat64.Dense {
+    m := mat64.NewDense(n, n, nil)
     for i := 0; i < n; i++ {
-        a[i] = 1
-        m[i] = a[:n]
-        a = a[n:]
+        m.Set(i, i, 1)
     }
     return m
 }
+
+func main() {
+    fmt.Println(mat64.Formatted(eye(3)))
+}

Task/Identity-matrix/Go/identity-matrix-2.go

@@ -1,18 +1,11 @@
 package main
 
-import "fmt"
+import (
+    "fmt"
 
-type matrix []float64
+    mat "github.com/skelterjohn/go.matrix"
+)
 
 func main() {
-    fmt.Println(I(3))
-}
-
-func I(n int) matrix {
-    m := make(matrix, n*n)
-    n++
-    for i := 0; i < len(m); i += n {
-        m[i] = 1
-    }
-    return m
+    fmt.Println(mat.Eye(3))
 }

Task/Identity-matrix/Go/identity-matrix-3.go

@@ -1,11 +1,17 @@
 package main
 
-import (
-    "fmt"
-
-    mat "github.com/skelterjohn/go.matrix"
-)
+import "fmt"
 
 func main() {
-    fmt.Println(mat.Eye(3))
+    fmt.Println(I(3))
+}
+
+func I(n int) [][]float64 {
+    m := make([][]float64, n)
+    for i := 0; i < n; i++ {
+        a := make([]float64, n)
+        a[i] = 1
+        m[i] = a
+    }
+    return m
 }

Task/Identity-matrix/Go/identity-matrix-4.go

@@ -0,0 +1,18 @@
+package main
+
+import "fmt"
+
+func main() {
+    fmt.Println(I(3))
+}
+
+func I(n int) [][]float64 {
+    m := make([][]float64, n)
+    a := make([]float64, n*n)
+    for i := 0; i < n; i++ {
+        a[i] = 1
+        m[i] = a[:n]
+        a = a[n:]
+    }
+    return m
+}

Task/Identity-matrix/Go/identity-matrix-5.go

@@ -0,0 +1,34 @@
+package main
+
+import "fmt"
+
+type matrix []float64
+
+func main() {
+    n := 3
+    m := I(n)
+    // dump flat represenation
+    fmt.Println(m)
+
+    // function x turns a row and column into an index into the
+    // flat representation.
+    x := func(r, c int) int { return r*n + c }
+
+    // access m by row and column.
+    for r := 0; r < n; r++ {
+        for c := 0; c < n; c++ {
+            fmt.Print(m[x(r, c)], " ")
+        }
+        fmt.Println()
+    }
+}
+
+func I(n int) matrix {
+    m := make(matrix, n*n)
+    // a fast way to initialize the flat representation
+    n++
+    for i := 0; i < len(m); i += n {
+        m[i] = 1
+    }
+    return m
+}

Task/Identity-matrix/Perl-6/identity-matrix-1.pl6

@@ -1,6 +1,6 @@
 sub identity-matrix($n) {
     my @id;
-    for ^$n X ^$n -> $i, $j {
+    for flat ^$n X ^$n -> $i, $j {
         @id[$i][$j] = +($i == $j);
     }
     @id;

Task/Identity-matrix/Perl-6/identity-matrix-3.pl6

@@ -1,3 +1,3 @@
 sub identity-matrix($n) {
-    [1, 0 xx $n-1], *.rotate(-1).item ... *[*-1] == 1
+    ([1, |(0 xx $n-1)].item, *.rotate(-1).item ... *)[^$n]
 }

Task/Identity-matrix/PowerShell/identity-matrix-1.psh

@@ -0,0 +1,21 @@
+function id($n) {
+    if($n -gt 0) {
+        $array = @(1..$n | foreach{ @(0) })
+        0..($n-1) | foreach{
+            $i = $_
+            $array[$i] = @(switch(0..($n-1)){
+                $i {1}
+                default {0}
+            })
+        }
+        $array
+    } else { @() }
+}
+function show($a) {
+    if($a.Count -gt 0) {
+        $n = $a.Count - 1
+        0..$n | foreach{ "$($a[$_][0..$n])" }
+    }
+}
+$array = id 4
+show $array

Task/Identity-matrix/PowerShell/identity-matrix-2.psh

@@ -0,0 +1,2 @@
+$array[0][0]
+$array[0][1]

Task/Identity-matrix/VBScript/identity-matrix.vb

@@ -0,0 +1,29 @@
+build_matrix(7)
+
+Sub build_matrix(n)
+	Dim matrix()
+	ReDim matrix(n-1,n-1)
+	i = 0
+	'populate the matrix
+	For row = 0 To n-1
+		For col = 0 To n-1
+			If col = i Then
+				matrix(row,col) = 1
+			Else
+				matrix(row,col) = 0
+			End If	
+		Next
+		i = i + 1
+	Next
+	'display the matrix
+	For row = 0 To n-1
+		For col = 0 To n-1
+			If col < n-1 Then
+				WScript.StdOut.Write matrix(row,col) & " "
+			Else
+				WScript.StdOut.Write matrix(row,col)
+			End If
+		Next
+		WScript.StdOut.WriteLine
+	Next
+End Sub