Data commit

Task/Identity-matrix/00-META.yaml

@@ -0,0 +1,4 @@
+---
+category:
+- Matrices
+from: http://rosettacode.org/wiki/Identity_matrix

Task/Identity-matrix/00-TASK.txt

@@ -0,0 +1,24 @@
+;Task:
+Build an   [[wp:identity matrix|identity matrix]]   of a size known at run-time. 
+
+
+An ''identity matrix'' is a square matrix of size '''''n'' × ''n''''', 
+<br>where the diagonal elements are all '''1'''s (ones), 
+<br>and all the other elements are all '''0'''s (zeroes).
+
+
+<math>I_n = \begin{bmatrix}
+  1      & 0      & 0      & \cdots & 0      \\
+  0      & 1      & 0      & \cdots & 0      \\
+  0      & 0      & 1      & \cdots & 0      \\
+  \vdots & \vdots & \vdots & \ddots & \vdots \\
+  0      & 0      & 0      & \cdots & 1      \\
+\end{bmatrix}</math>
+
+
+;Related tasks:
+* &nbsp; [[Spiral matrix]]
+* &nbsp; [[Zig-zag matrix]] 
+* &nbsp; [[Ulam_spiral_(for_primes)]]
+<br><br>
+

Task/Identity-matrix/11l/identity-matrix.11l

@@ -0,0 +1,8 @@
+F identity_matrix(size)
+   V matrix = [[0] * size] * size
+   L(i) 0 .< size
+      matrix[i][i] = 1
+   R matrix
+
+L(row) identity_matrix(3)
+   print(row)

Task/Identity-matrix/360-Assembly/identity-matrix.360

@@ -0,0 +1,73 @@
+*        Identity matrix           31/03/2017
+INDENMAT CSECT
+         USING  INDENMAT,R13       base register
+         B      72(R15)            skip savearea
+         DC     17F'0'             savearea
+         STM    R14,R12,12(R13)    save previous context
+         ST     R13,4(R15)         link backward
+         ST     R15,8(R13)         link forward
+         LR     R13,R15            set addressability
+         L      R1,N               n
+         MH     R1,N+2             n*n
+         SLA    R1,2               *4
+         ST     R1,LL              amount of storage required
+         GETMAIN RU,LV=(R1)        allocate storage for matrix
+         USING  DYNA,R11           make storage addressable
+         LR     R11,R1             set addressability
+         LA     R6,1               i=1
+       DO WHILE=(C,R6,LE,N)        do i=1 to n
+         LA     R7,1                 j=1
+       DO WHILE=(C,R7,LE,N)          do j=1 to n
+       IF CR,R6,EQ,R7 THEN             if i=j then
+         LA     R2,1                     k=1
+       ELSE     ,                      else
+         LA     R2,0                     k=0
+       ENDIF    ,                      endif
+         LR     R1,R6                  i
+         BCTR   R1,0                   -1
+         MH     R1,N+2                 *n
+         AR     R1,R7                  (i-1)*n+j
+         BCTR   R1,0                   -1
+         SLA    R1,2                   *4
+         ST     R2,A(R1)               a(i,j)=k
+         LA     R7,1(R7)               j++
+       ENDDO    ,                    enddo j
+         LA     R6,1(R6)             i++
+       ENDDO    ,                  enddo i
+         LA     R6,1               i=1
+       DO WHILE=(C,R6,LE,N)        do i=1 to n
+         LA     R10,PG               pgi=0
+         LA     R7,1                 j=1
+       DO WHILE=(C,R7,LE,N)          do j=1 to n
+         LR     R1,R6                  i
+         BCTR   R1,0                   -1
+         MH     R1,N+2                 *n
+         AR     R1,R7                  (i-1)*n+j
+         BCTR   R1,0                   -1
+         SLA    R1,2                   *4
+         L      R2,A(R1)               a(i,j)
+         XDECO  R2,XDEC                edit
+         MVC    0(1,R10),XDEC+11       output
+         LA     R10,1(R10)             pgi+=1
+         LA     R7,1(R7)               j++
+       ENDDO    ,                    enddo j
+         XPRNT  PG,L'PG              print
+         LA     R6,1(R6)             i++
+       ENDDO    ,                  enddo i
+         LA     R1,A               address to free
+         LA     R2,LL              amount of storage to free
+         FREEMAIN A=(R1),LV=(R2)   free allocated storage
+         DROP   R11                drop register
+         L      R13,4(0,R13)       restore previous savearea pointer
+         LM     R14,R12,12(R13)    restore previous context
+         XR     R15,R15            rc=0
+         BR     R14                exit
+NN       EQU    10                 parameter n  (90=>32K)
+N        DC     A(NN)              n
+LL       DS     F                  n*n*4
+PG       DC     CL(NN)' '          buffer
+XDEC     DS     CL12               temp
+DYNA     DSECT
+A        DS     F                  a(n,n)
+         YREGS
+         END    INDENMAT

Task/Identity-matrix/ALGOL-68/identity-matrix-1.alg

@@ -0,0 +1,33 @@
+#!/usr/bin/a68g --script #
+# -*- coding: utf-8 -*- #
+
+# Define some generic vector initialisation and printing operations #
+
+COMMENT REQUIRES:
+  MODE SCAL = ~ # a scalar, eg REAL #;
+  FORMAT scal fmt := ~;
+END COMMENT
+
+INT vec lwb := 1, vec upb := 0;
+MODE VECNEW = [vec lwb:vec upb]SCAL; MODE VEC = REF VECNEW;
+FORMAT vec fmt := $"("n(vec upb-vec lwb)(f(scal fmt)", ")f(scal fmt)")"$;
+
+PRIO INIT = 1;
+
+OP INIT = (VEC self, SCAL scal)VEC: (
+  FOR col FROM LWB self TO UPB self DO self[col]:= scal OD;
+  self
+);
+
+# ZEROINIT: defines the additive identity #
+OP ZEROINIT = (VEC self)VEC:
+  self INIT SCAL(0);
+
+OP REPR = (VEC self)STRING: (
+  FILE f; STRING s; associate(f,s);
+  vec lwb := LWB self; vec upb := UPB self;
+  putf(f, (vec fmt, self)); close(f);
+  s
+);
+
+SKIP

Task/Identity-matrix/ALGOL-68/identity-matrix-2.alg

@@ -0,0 +1,52 @@
+# -*- coding: utf-8 -*- #
+
+# Define some generic matrix initialisation and printing operations #
+
+COMMENT REQUIRES:
+  MODE SCAL = ~ # a scalar, eg REAL #;
+  MODE VEC = []SCAL;
+  FORMAT scal fmt := ~;
+  et al.
+END COMMENT
+
+INT mat lwb := 1, mat upb := 0;
+MODE MATNEW = [mat lwb:mat upb, vec lwb: vec upb]SCAL; MODE MAT = REF MATNEW;
+FORMAT mat fmt = $"("n(vec upb-vec lwb)(f(vec fmt)","lx)f(vec fmt)")"l$;
+
+PRIO DIAGINIT = 1;
+
+OP INIT = (MAT self, SCAL scal)MAT: (
+  FOR row FROM LWB self TO UPB self DO self[row,] INIT scal OD;
+  self
+);
+
+# ZEROINIT: defines the additive identity #
+OP ZEROINIT = (MAT self)MAT:
+  self INIT SCAL(0);
+
+OP REPR = (MATNEW self)STRING: (
+  FILE f; STRING s; associate(f,s);
+  vec lwb := 2 LWB self; vec upb := 2 UPB self;
+  mat lwb :=   LWB self; mat upb :=   UPB self;
+  putf(f, (mat fmt, self)); close(f);
+  s
+);
+
+OP DIAGINIT = (MAT self, VEC diag)MAT: (
+  ZEROINIT self;
+  FOR d FROM LWB diag TO UPB diag DO self[d,d]:= diag[d] OD;
+# or alternatively using TORRIX ...
+  DIAG self := diag;
+#
+  self
+);
+
+# ONEINIT: defines the multiplicative identity #
+OP ONEINIT = (MAT self)MAT: (
+  ZEROINIT self DIAGINIT (LOC[LWB self:UPB self]SCAL INIT SCAL(1))
+# or alternatively using TORRIX ...
+  (DIAG out) VECINIT SCAL(1)
+#
+);
+
+SKIP

Task/Identity-matrix/ALGOL-68/identity-matrix-3.alg

@@ -0,0 +1,11 @@
+# -*- coding: utf-8 -*- #
+
+PRIO IDENT = 9; # The same as I for COMPLex #
+
+OP IDENT = (INT lwb, upb)MATNEW:
+  ONEINIT LOC [lwb:upb,lwb:upb]SCAL;
+
+OP IDENT = (INT upb)MATNEW: # default lwb is 1 #
+  1 IDENT upb;
+
+SKIP

Task/Identity-matrix/ALGOL-68/identity-matrix-4.alg

@@ -0,0 +1,8 @@
+#!/usr/bin/a68g --script #
+# -*- coding: utf-8 -*- #
+
+PR READ "prelude/vector_base.a68" PR;
+PR READ "prelude/matrix_base.a68" PR;
+PR READ "prelude/matrix_ident.a68" PR;
+
+SKIP

Task/Identity-matrix/ALGOL-68/identity-matrix-5.alg

@@ -0,0 +1,9 @@
+#!/usr/bin/a68g --script #
+# -*- coding: utf-8 -*- #
+
+MODE SCAL = REAL;
+FORMAT scal fmt := $g(-3,1)$;
+
+PR READ "prelude/matrix.a68" PR;
+
+print(REPR IDENT 4)

Task/Identity-matrix/ALGOL-W/identity-matrix.alg

@@ -0,0 +1,22 @@
+begin
+    % set m to an identity matrix of size s                                  %
+    procedure makeIdentity( real    array m ( *, * )
+                          ; integer value s
+                          ) ;
+        for i := 1 until s do begin
+            for j := 1 until s do m( i, j ) := 0.0;
+            m( i, i ) := 1.0
+        end makeIdentity ;
+
+    % test the makeIdentity procedure                                        %
+    begin
+        real array id5( 1 :: 5, 1 :: 5 );
+        makeIdentity( id5, 5 );
+        r_format := "A"; r_w := 6; r_d := 1; % set output format for reals   %
+        for i := 1 until 5 do begin
+            write();
+            for j := 1 until 5 do writeon( id5( i, j ) )
+        end for_i ;
+    end text
+
+end.

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

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

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

@@ -0,0 +1,7 @@
+    ID←{∘.=⍨⍳⍵}
+    ID 5
+1 0 0 0 0
+0 1 0 0 0
+0 0 1 0 0
+0 0 0 1 0
+0 0 0 0 1

Task/Identity-matrix/APL/identity-matrix-3.apl

@@ -0,0 +1,2 @@
+    ID←∘.=⍨⍳
+    ID←⍳∘.=⍳

Task/Identity-matrix/APL/identity-matrix-4.apl

@@ -0,0 +1 @@
+    ID←{⍵ ⍵ ρ 1, ⍵ρ0}

Task/Identity-matrix/ATS/identity-matrix.ats

@@ -0,0 +1,33 @@
+(* ****** ****** *)
+//
+// How to compile:
+//
+// patscc -DATS_MEMALLOC_LIBC -o idmatrix idmatrix.dats
+//
+(* ****** ****** *)
+//
+#include
+"share/atspre_staload.hats"
+//
+(* ****** ****** *)
+
+extern
+fun
+idmatrix{n:nat}(n: size_t(n)): matrixref(int, n, n)
+implement
+idmatrix(n) =
+matrixref_tabulate_cloref<int> (n, n, lam(i, j) => bool2int0(i = j))
+
+(* ****** ****** *)
+
+implement
+main0 () =
+{
+//
+val N = 5
+//
+val M = idmatrix(i2sz(N))
+val () = fprint_matrixref_sep (stdout_ref, M, i2sz(N), i2sz(N), " ", "\n")
+val () = fprint_newline (stdout_ref)
+//
+} (* end of [main0] *)

Task/Identity-matrix/AWK/identity-matrix.awk

@@ -0,0 +1,17 @@
+# syntax: GAWK -f IDENTITY_MATRIX.AWK size
+BEGIN {
+    size = ARGV[1]
+    if (size !~ /^[0-9]+$/) {
+      print("size invalid or missing from command line")
+      exit(1)
+    }
+    for (i=1; i<=size; i++) {
+      for (j=1; j<=size; j++) {
+        x = (i == j) ? 1 : 0
+        printf("%2d",x) # print
+        arr[i,j] = x # build
+      }
+      printf("\n")
+    }
+    exit(0)
+}

Task/Identity-matrix/Action-/identity-matrix.action

@@ -0,0 +1,58 @@
+PROC CreateIdentityMatrix(BYTE ARRAY mat,BYTE size)
+  CARD pos
+  BYTE i,j
+
+  pos=0
+  FOR i=1 TO size
+  DO
+    FOR j=1 TO size
+    DO
+      IF i=j THEN
+        mat(pos)=1
+      ELSE
+        mat(pos)=0
+      FI
+      pos==+1
+    OD
+  OD
+RETURN
+
+PROC PrintMatrix(BYTE ARRAY mat,BYTE size)
+  CARD pos
+  BYTE i,j,v
+
+  pos=0
+  FOR i=1 TO size
+  DO
+    FOR j=1 TO size
+    DO
+      v=mat(pos)
+      IF j=size THEN
+        PrintF("%I%E",v)
+      ELSE
+        PrintF("%I ",v)
+      FI
+      pos==+1
+    OD
+  OD
+RETURN
+
+PROC Main()
+  BYTE size
+  BYTE ARRAY mat(400)
+  BYTE LMARGIN=$52,old
+
+  old=LMARGIN
+  LMARGIN=0 ;remove left margin on the screen
+
+  DO
+    Print("Get size of matrix [1-20] ")
+    size=InputB()
+  UNTIL size>=1 AND size<=20
+  OD
+
+  CreateIdentityMatrix(mat,size)
+  PrintMatrix(mat,size)
+
+  LMARGIN=old ;restore left margin on the screen
+RETURN

Task/Identity-matrix/Ada/identity-matrix-1.ada

@@ -0,0 +1,4 @@
+--  As prototyped in the Generic_Real_Arrays specification:
+--  function Unit_Matrix (Order : Positive; First_1, First_2 : Integer := 1) return Real_Matrix;
+-- For the task:
+mat : Real_Matrix := Unit_Matrix(5);

Task/Identity-matrix/Ada/identity-matrix-2.ada

@@ -0,0 +1,4 @@
+type Matrix is array(Positive Range <>, Positive Range <>) of Integer;
+mat : Matrix(1..5,1..5) := (others => (others => 0));
+--  then after the declarative section:
+for i in mat'Range(1) loop mat(i,i) := 1; end loop;

Task/Identity-matrix/AppleScript/identity-matrix-1.applescript

@@ -0,0 +1,108 @@
+--------------------- IDENTITY MATRIX ----------------------
+
+-- identityMatrix :: Int -> [(0|1)]
+on identityMatrix(n)
+    set xs to enumFromTo(1, n)
+
+    script row
+        on |λ|(x)
+            script col
+                on |λ|(i)
+                    if i = x then
+                        1
+                    else
+                        0
+                    end if
+                end |λ|
+            end script
+            map(col, xs)
+        end |λ|
+    end script
+
+    map(row, xs)
+end identityMatrix
+
+
+--------------------------- TEST ---------------------------
+on run
+
+    unlines(map(showList, ¬
+        identityMatrix(5)))
+
+end run
+
+
+-------------------- GENERIC FUNCTIONS ---------------------
+
+-- enumFromTo :: Int -> Int -> [Int]
+on enumFromTo(m, n)
+    if m ≤ n then
+        set lst to {}
+        repeat with i from m to n
+            set end of lst to i
+        end repeat
+        lst
+    else
+        {}
+    end if
+end enumFromTo
+
+
+-- intercalate :: String -> [String] -> String
+on intercalate(delim, xs)
+    set {dlm, my text item delimiters} to ¬
+        {my text item delimiters, delim}
+    set s to xs as text
+    set my text item delimiters to dlm
+    s
+end intercalate
+
+
+-- map :: (a -> b) -> [a] -> [b]
+on map(f, xs)
+    tell mReturn(f)
+        set lng to length of xs
+        set lst to {}
+        repeat with i from 1 to lng
+            set end of lst to |λ|(item i of xs, i, xs)
+        end repeat
+        return lst
+    end tell
+end map
+
+
+-- Lift 2nd class handler function into 1st class script wrapper
+-- mReturn :: Handler -> Script
+on mReturn(f)
+    if class of f is script then
+        f
+    else
+        script
+            property |λ| : f
+        end script
+    end if
+end mReturn
+
+
+-- showList :: [a] -> String
+on showList(xs)
+    "[" & intercalate(", ", map(my str, xs)) & "]"
+end showList
+
+
+-- str :: a -> String
+on str(x)
+    x as string
+end str
+
+
+-- unlines :: [String] -> String
+on unlines(xs)
+    -- A single string formed by the intercalation
+    -- of a list of strings with the newline character.
+    set {dlm, my text item delimiters} to ¬
+        {my text item delimiters, linefeed}
+    set s to xs as text
+    set my text item delimiters to dlm
+    s
+end unlines

Task/Identity-matrix/AppleScript/identity-matrix-2.applescript

@@ -0,0 +1,17 @@
+on indentityMatrix(n)
+    set digits to {}
+    set m to n - 1
+    repeat (n + m) times
+        set end of digits to 0
+    end repeat
+    set item n of digits to 1
+
+    set matrix to {}
+    repeat with i from n to 1 by -1
+        set end of matrix to items i thru (i + m) of digits
+    end repeat
+
+    return matrix
+end indentityMatrix
+
+return indentityMatrix(5)

Task/Identity-matrix/AppleScript/identity-matrix-3.applescript

@@ -0,0 +1 @@
+{{1, 0, 0, 0, 0}, {0, 1, 0, 0, 0}, {0, 0, 1, 0, 0}, {0, 0, 0, 1, 0}, {0, 0, 0, 0, 1}}

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

@@ -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/Arturo/identity-matrix.arturo

@@ -0,0 +1,11 @@
+identityM: function [n][
+    result: array.of: @[n n] 0
+    loop 0..dec n 'i -> result\[i]\[i]: 1
+    return result
+]
+
+loop 4..6 'sz [
+    print sz
+    loop identityM sz => print
+    print ""
+]

Task/Identity-matrix/AutoHotkey/identity-matrix.ahk

@@ -0,0 +1,16 @@
+msgbox % Clipboard := I(6)
+return
+
+I(n){
+    r := "--`n" , s := " "
+    loop % n
+    {
+        k := A_index , r .= "|  "
+        loop % n
+            r .= A_index=k ? "1, " : "0, "
+        r := RTrim(r, " ,") , r .= "  |`n"
+    }
+    loop % 4*n
+        s .= " "
+    return Rtrim(r,"`n") "`n" s "--"
+}

Task/Identity-matrix/BASIC256/identity-matrix.basic

@@ -0,0 +1,25 @@
+arraybase 1
+do
+    input "Enter size of matrix: ", n
+until n > 0
+
+dim identity(n, n) fill 0  #we fill everything with 0
+
+# enter 1s in diagonal elements
+for i =  1 to n
+    identity[i, i] = 1
+next i
+
+# print identity matrix if n < 40
+print
+
+if n < 40 then
+    for i = 1 to n
+        for j = 1 to n
+            print identity[i, j];
+        next j
+        print
+    next i
+else
+    print "Matrix is too big to display on 80 column console"
+end if

Task/Identity-matrix/BBC-BASIC/identity-matrix.basic

@@ -0,0 +1,17 @@
+      INPUT "Enter size of matrix: " size%
+      PROCidentitymatrix(size%, im())
+      FOR r% = 0 TO size%-1
+        FOR c% = 0 TO size%-1
+          PRINT im(r%, c%),;
+        NEXT
+        PRINT
+      NEXT r%
+      END
+
+      DEF PROCidentitymatrix(s%, RETURN m())
+      LOCAL i%
+      DIM m(s%-1, s%-1)
+      FOR i% = 0 TO s%-1
+        m(i%,i%) = 1
+      NEXT
+      ENDPROC

Task/Identity-matrix/BQN/identity-matrix-1.bqn

@@ -0,0 +1,7 @@
+⍝ Using table
+Eye ← =⌜˜∘↕
+•Show Eye 3
+
+⍝ Using reshape
+Eye1 ← {𝕩‿𝕩⥊1∾𝕩⥊0}
+Eye1 5

Task/Identity-matrix/BQN/identity-matrix-2.bqn

@@ -0,0 +1,12 @@
+┌─
+╵ 1 0 0
+  0 1 0
+  0 0 1
+        ┘
+┌─
+╵ 1 0 0 0 0
+  0 1 0 0 0
+  0 0 1 0 0
+  0 0 0 1 0
+  0 0 0 0 1
+            ┘

Task/Identity-matrix/Beads/identity-matrix.beads

@@ -0,0 +1,10 @@
+beads 1 program 'Identity matrix'
+
+var
+	id : array^2 of num
+	n = 5
+	
+calc main_init
+	loop from:1 to:n index:i
+		loop from:1 to:n index:j
+			id[i,j] = 1 if i == j else 0

Task/Identity-matrix/Burlesque/identity-matrix-1.blq

@@ -0,0 +1,7 @@
+blsq ) 6 -.^^0\/r@\/'0\/.*'1+]\/{\/{rt}\/E!XX}x/+]m[sp
+1 0 0 0 0 0
+0 1 0 0 0 0
+0 0 1 0 0 0
+0 0 0 1 0 0
+0 0 0 0 1 0
+0 0 0 0 0 1

Task/Identity-matrix/Burlesque/identity-matrix-2.blq

@@ -0,0 +1 @@
+6hd0bx#a.*\[#a.*0#a?dr@{(D!)\/1\/^^bx\/[+}m[e!

Task/Identity-matrix/Burlesque/identity-matrix-3.blq

@@ -0,0 +1 @@
+blsq ) 6 ^^^^10\/**XXcy\/co.+sp

Task/Identity-matrix/C++/identity-matrix-1.cpp

@@ -0,0 +1,47 @@
+template<class T>
+class matrix
+{
+public:
+    matrix( unsigned int nSize ) :
+      m_oData(nSize * nSize, 0), m_nSize(nSize) {}
+
+      inline T& operator()(unsigned int x, unsigned int y)
+      {
+          return m_oData[x+m_nSize*y];
+      }
+
+      void identity()
+      {
+          int nCount = 0;
+          int nStride = m_nSize + 1;
+          std::generate( m_oData.begin(), m_oData.end(),
+              [&]() { return !(nCount++%nStride); } );
+      }
+
+      inline unsigned int size() { return m_nSize; }
+
+private:
+    std::vector<T>    m_oData;
+    unsigned int      m_nSize;
+};
+
+int main()
+{
+    int nSize;
+    std::cout << "Enter matrix size (N): ";
+    std::cin >> nSize;
+
+    matrix<int> oMatrix( nSize );
+
+    oMatrix.identity();
+
+    for ( unsigned int y = 0; y < oMatrix.size(); y++ )
+    {
+        for ( unsigned int x = 0; x < oMatrix.size(); x++ )
+        {
+            std::cout << oMatrix(x,y) << " ";
+        }
+        std::cout << std::endl;
+    }
+    return 0;
+}

Task/Identity-matrix/C++/identity-matrix-2.cpp

@@ -0,0 +1,23 @@
+#include <boost/numeric/ublas/matrix.hpp>
+
+int main()
+{
+    using namespace boost::numeric::ublas;
+
+    int nSize;
+    std::cout << "Enter matrix size (N): ";
+    std::cin >> nSize;
+
+    identity_matrix<int> oMatrix( nSize );
+
+    for ( unsigned int y = 0; y < oMatrix.size2(); y++ )
+    {
+        for ( unsigned int x = 0; x < oMatrix.size1(); x++ )
+        {
+            std::cout << oMatrix(x,y) << " ";
+        }
+        std::cout << std::endl;
+    }
+
+    return 0;
+}

Task/Identity-matrix/C-sharp/identity-matrix.cs

@@ -0,0 +1,35 @@
+using System;
+using System.Linq;
+
+namespace IdentityMatrix
+{
+    class Program
+    {
+        static void Main(string[] args)
+        {
+            if (args.Length != 1)
+            {
+                Console.WriteLine("Requires exactly one argument");
+                return;
+            }
+            int n;
+            if (!int.TryParse(args[0], out n))
+            {
+                Console.WriteLine("Requires integer parameter");
+                return;
+            }
+
+            var identity =
+                Enumerable.Range(0, n).Select(i => Enumerable.Repeat(0, n).Select((z,j) => j == i ? 1 : 0).ToList()).ToList();
+            foreach (var row in identity)
+            {
+                foreach (var elem in row)
+                {
+                    Console.Write(" " + elem);
+                }
+                Console.WriteLine();
+            }
+            Console.ReadKey();
+        }
+    }
+}

Task/Identity-matrix/C/identity-matrix.c

@@ -0,0 +1,38 @@
+#include <stdlib.h>
+#include <stdio.h>
+int main(int argc, char** argv) {
+   if (argc < 2) {
+      printf("usage: identitymatrix <number of rows>\n");
+      exit(EXIT_FAILURE);
+   }
+   int rowsize = atoi(argv[1]);
+   if (rowsize < 0) {
+      printf("Dimensions of matrix cannot be negative\n");
+      exit(EXIT_FAILURE);
+   }
+   int numElements = rowsize * rowsize;
+   if (numElements < rowsize) {
+      printf("Squaring %d caused result to overflow to %d.\n", rowsize, numElements);
+      abort();
+   }
+   int** matrix = calloc(numElements, sizeof(int*));
+   if (!matrix) {
+      printf("Failed to allocate %d elements of %ld bytes each\n", numElements, sizeof(int*));
+      abort();
+   }
+   for (unsigned int row = 0;row < rowsize;row++) {
+      matrix[row] = calloc(numElements, sizeof(int));
+      if (!matrix[row]) {
+         printf("Failed to allocate %d elements of %ld bytes each\n", numElements, sizeof(int));
+         abort();
+      }
+      matrix[row][row] = 1;
+   }
+   printf("Matrix is: \n");
+   for (unsigned int row = 0;row < rowsize;row++) {
+      for (unsigned int column = 0;column < rowsize;column++) {
+         printf("%d ", matrix[row][column]);
+      }
+      printf("\n");
+   }
+}

Task/Identity-matrix/Clio/identity-matrix.clio

@@ -0,0 +1,6 @@
+fn identity-matrix n:
+  [0:n] -> * fn i:
+    [0:n] -> * if = i: 1
+                 else: 0
+
+5 -> identity-matrix -> * print

Task/Identity-matrix/Clojure/identity-matrix-1.clj

@@ -0,0 +1 @@
+ '( (0 1) (2 3) )

Task/Identity-matrix/Clojure/identity-matrix-2.clj

@@ -0,0 +1,6 @@
+(defn identity-matrix [n]
+  (let [row (conj (repeat (dec n) 0) 1)]
+    (vec
+      (for [i (range 1 (inc n))]
+        (vec
+          (reduce conj (drop i row ) (take i row)))))))

Task/Identity-matrix/Clojure/identity-matrix-3.clj

@@ -0,0 +1,2 @@
+=> (identity-matrix 5)
+[[1 0 0 0 0] [0 1 0 0 0] [0 0 1 0 0] [0 0 0 1 0] [0 0 0 0 1]]

Task/Identity-matrix/Clojure/identity-matrix-4.clj

@@ -0,0 +1,4 @@
+(defn identity-matrix [n]
+  (take n
+    (partition n (dec n)
+                         (cycle (conj (repeat (dec n) 0) 1)))))

Task/Identity-matrix/Commodore-BASIC/identity-matrix.basic

@@ -0,0 +1,17 @@
+100 INPUT "MATRIX SIZE:"; SIZE
+110 GOSUB 200: REM IDENTITYMATRIX
+120 FOR R = 0 TO SIZE
+130 FOR C = 0 TO SIZE
+140 S$ = CHR$(13)
+150 IF C < SIZE THEN S$ = ""
+160 PRINT MID$(STR$(IM(R, C)),1)S$;:REM MID$ STRIPS LEADING SPACES
+170 NEXT C, R
+180 END
+190 REM *******************************
+200 REM IDENTITYMATRIX SIZE%
+210 SIZE = SIZE - 1
+220 DIM IM(SIZE, SIZE)
+230 FOR I = 0 TO SIZE
+240     IM(I, I) = 1
+250 NEXT I
+260 RETURN

Task/Identity-matrix/Common-Lisp/identity-matrix-1.lisp

@@ -0,0 +1,4 @@
+(defun make-identity-matrix (n)
+  (let ((array (make-array (list n n) :initial-element 0)))
+    (loop for i below n do (setf (aref array i i) 1))
+    array))

Task/Identity-matrix/Common-Lisp/identity-matrix-2.lisp

@@ -0,0 +1,5 @@
+(defun identity-matrix (n)
+  (loop for a from 1 to n
+        collect (loop for e from 1 to n
+                      if (= a e) collect 1
+                      else collect 0)))

Task/Identity-matrix/Component-Pascal/identity-matrix.pas

@@ -0,0 +1,35 @@
+MODULE Algebras;
+IMPORT StdLog,Strings;
+
+TYPE
+	Matrix = POINTER TO ARRAY OF ARRAY OF INTEGER;
+	
+PROCEDURE NewIdentityMatrix(n: INTEGER): Matrix;
+VAR
+	m: Matrix;
+	i: INTEGER;
+BEGIN
+	NEW(m,n,n);
+	FOR i := 0 TO n - 1 DO
+		m[i,i] := 1;
+	END;
+	RETURN m;
+END NewIdentityMatrix;
+
+PROCEDURE Show(m: Matrix);
+VAR
+	i,j: INTEGER;
+BEGIN
+	FOR i := 0 TO LEN(m,0) - 1 DO
+		FOR j := 0 TO LEN(m,1) - 1 DO
+			StdLog.Int(m[i,j]);
+		END;
+		StdLog.Ln
+	END
+END Show;
+
+PROCEDURE Do*;
+BEGIN
+	Show(NewIdentityMatrix(5));
+END Do;
+END Algebras.

Task/Identity-matrix/D/identity-matrix.d

@@ -0,0 +1,30 @@
+import std.traits;
+
+T[][] matId(T)(in size_t n) pure nothrow if (isAssignable!(T, T)) {
+    auto Id = new T[][](n, n);
+
+    foreach (r, row; Id) {
+        static if (__traits(compiles, {row[] = 0;})) {
+            row[] = 0; // vector op doesn't work with T = BigInt
+            row[r] = 1;
+        } else {
+            foreach (c; 0 .. n)
+                row[c] = (c == r) ? 1 : 0;
+        }
+    }
+
+    return Id;
+}
+
+void main() {
+    import std.stdio, std.bigint;
+    enum form = "[%([%(%s, %)],\n %)]]";
+
+    immutable id1 = matId!real(5);
+    writefln(form ~ "\n", id1);
+
+    immutable id2 = matId!BigInt(3);
+    writefln(form ~ "\n", id2);
+
+    // auto id3 = matId!(const int)(2); // cant't compile
+}

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/ERRE/identity-matrix.erre

@@ -0,0 +1,20 @@
+PROGRAM IDENTITY
+
+!$DYNAMIC
+DIM A[0,0]
+
+BEGIN
+  PRINT(CHR$(12);) ! CLS
+  INPUT("Matrix size",N%)
+  !$DIM A[N%,N%]
+  FOR I%=1 TO N% DO
+    A[I%,I%]=1
+  END FOR
+! print matrix
+  FOR I%=1 TO N% DO
+    FOR J%=1 TO N% DO
+      WRITE("###";A[I%,J%];)
+    END FOR
+    PRINT
+  END FOR
+END PROGRAM

Task/Identity-matrix/Eiffel/identity-matrix.e

@@ -0,0 +1,61 @@
+class
+	APPLICATION
+
+inherit
+	ARGUMENTS
+
+create
+	make
+
+feature {NONE} -- Initialization
+
+	make
+			-- Run application.
+		local
+		    dim : INTEGER -- Dimension of the identity matrix
+		do
+		    from dim := 1 until dim > 10 loop
+		    	print_matrix( identity_matrix(dim) )
+				dim := dim + 1
+				io.new_line
+			end
+
+		end
+
+feature -- Access
+
+	identity_matrix(dim : INTEGER) : ARRAY2[REAL_64]
+
+		require
+			dim > 0
+		local
+			matrix : ARRAY2[REAL_64]
+			i : INTEGER
+		do
+
+			create matrix.make_filled (0.0, dim, dim)
+			from i := 1 until i > dim loop
+				matrix.put(1.0, i, i)
+				i := i + 1
+			end
+
+			Result := matrix
+		end
+
+	print_matrix(matrix : ARRAY2[REAL_64])
+		local
+			i, j : INTEGER
+		do
+			from i := 1 until i > matrix.height loop
+				print("[ ")
+				from j := 1 until j > matrix.width loop
+					print(matrix.item (i, j))
+					print(" ")
+					j := j + 1
+				end
+				print("]%N")
+				i := i + 1
+			end
+		end
+
+end

Task/Identity-matrix/Elena/identity-matrix.elena

@@ -0,0 +1,14 @@
+import extensions;
+import system'routines;
+import system'collections;
+
+public program()
+{
+    var n := console.write:"Enter the matrix size:".readLine().toInt();
+
+    var identity := new Range(0, n).selectBy:(i => new Range(0,n).selectBy:(j => (i == j).iif(1,0) ).summarize(new ArrayList()))
+                         .summarize(new ArrayList());
+
+    identity.forEach:
+        (row) { console.printLine(row.asEnumerable()) }
+}

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/Erlang/identity-matrix.erl

@@ -0,0 +1,11 @@
+%% Identity Matrix in Erlang for the Rosetta Code Wiki.
+%% Implemented by Arjun Sunel
+
+-module(identity_matrix).
+-export([square_matrix/2 , identity/1]).
+
+square_matrix(Size, Elements) ->
+    [[Elements(Column, Row) || Column <- lists:seq(1, Size)] || Row <- lists:seq(1, Size)].
+
+identity(Size) ->
+    square_matrix(Size, fun(Column, Row) -> case Column of Row -> 1; _ -> 0 end end).

Task/Identity-matrix/Euler/identity-matrix-1.euler

@@ -0,0 +1,7 @@
+function IdentityMatrix(n)
+  $  X:=zeros(n,n);
+  $  for i=1 to n
+  $    X[i,i]:=1;
+  $  end;
+  $  return X;
+  $endfunction

Task/Identity-matrix/Euler/identity-matrix-2.euler

@@ -0,0 +1,3 @@
+>function IdentityMatrix (n:index)
+$  return setdiag(zeros(n,n),0,1);
+$endfunction

Task/Identity-matrix/Euler/identity-matrix-3.euler

@@ -0,0 +1 @@
+>id(5)

Task/Identity-matrix/Excel/identity-matrix.excel

@@ -0,0 +1,13 @@
+IDMATRIX
+=LAMBDA(n,
+    LET(
+        ixs, SEQUENCE(n, n, 0, 1),
+        x, MOD(ixs, n),
+        y, QUOTIENT(ixs, n),
+
+        IF(x = y,
+            1,
+            0
+        )
+    )
+)

Task/Identity-matrix/F-Sharp/identity-matrix-1.fs

@@ -0,0 +1 @@
+let ident n = Array2D.init n n (fun i j -> if i = j then 1 else 0)

Task/Identity-matrix/F-Sharp/identity-matrix-2.fs

@@ -0,0 +1,11 @@
+ident 10;;
+val it : int [,] = [[1; 0; 0; 0; 0; 0; 0; 0; 0; 0]
+                    [0; 1; 0; 0; 0; 0; 0; 0; 0; 0]
+                    [0; 0; 1; 0; 0; 0; 0; 0; 0; 0]
+                    [0; 0; 0; 1; 0; 0; 0; 0; 0; 0]
+                    [0; 0; 0; 0; 1; 0; 0; 0; 0; 0]
+                    [0; 0; 0; 0; 0; 1; 0; 0; 0; 0]
+                    [0; 0; 0; 0; 0; 0; 1; 0; 0; 0]
+                    [0; 0; 0; 0; 0; 0; 0; 1; 0; 0]
+                    [0; 0; 0; 0; 0; 0; 0; 0; 1; 0]
+                    [0; 0; 0; 0; 0; 0; 0; 0; 0; 1]]

Task/Identity-matrix/Factor/identity-matrix.factor

@@ -0,0 +1,3 @@
+USING: math.matrices prettyprint ;
+
+6 <identity-matrix> .

Task/Identity-matrix/Fermat/identity-matrix.fermat

@@ -0,0 +1,4 @@
+Func Identity(n)=Array id[n,n];[id]:=[1].
+
+Identity(7)
+[id]

Task/Identity-matrix/Forth/identity-matrix.fth

@@ -0,0 +1,16 @@
+S" fsl-util.fs" REQUIRED
+
+: build-identity ( 'p n -- 'p )  \ make an NxN identity matrix
+  0 DO
+    I 1+ 0 DO
+      I J = IF  1.0E0 DUP I J }} F!
+      ELSE
+        0.0E0 DUP J I }} F!
+        0.0E0 DUP I J }} F!
+      THEN
+    LOOP
+  LOOP ;
+
+6 6 float matrix a{{
+a{{ 6 build-identity
+6 6 a{{ }}fprint

Task/Identity-matrix/Fortran/identity-matrix-1.f

@@ -0,0 +1,23 @@
+program identitymatrix
+
+  real, dimension(:, :), allocatable :: I
+  character(len=8) :: fmt
+  integer :: ms, j
+
+  ms = 10   ! the desired size
+
+  allocate(I(ms,ms))
+  I = 0                           ! Initialize the array.
+  forall(j = 1:ms) I(j,j) = 1     ! Set the diagonal.
+
+  ! I is the identity matrix, let's show it:
+
+  write (fmt, '(A,I2,A)') '(', ms, 'F6.2)'
+  ! if you consider to have used the (row, col) convention,
+  ! the following will print the transposed matrix (col, row)
+  ! but I' = I, so it's not important here
+  write (*, fmt) I(:,:)
+
+  deallocate(I)
+
+end program identitymatrix

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/Fortran/identity-matrix-3.f

@@ -0,0 +1,3 @@
+      DO 1 I = 1,N
+        DO 1 J = 1,N
+    1     A(I,J) = (I/J)*(J/I)

Task/Identity-matrix/FreeBASIC/identity-matrix.basic

@@ -0,0 +1,32 @@
+' FB 1.05.0 Win64
+
+Dim As Integer n
+
+Do
+  Input "Enter size of matrix "; n
+Loop Until n > 0
+
+Dim identity(1 To n, 1 To n) As Integer '' all zero by default
+
+' enter 1s in diagonal elements
+For i As Integer =  1 To n
+  identity(i, i) = 1
+Next
+
+' print identity matrix if n < 40
+Print
+
+If n < 40 Then
+  For i As Integer = 1 To n
+    For j As Integer = 1 To n
+      Print identity(i, j);
+    Next j
+    Print
+  Next i
+Else
+  Print "Matrix is too big to display on 80 column console"
+End If
+
+Print
+Print "Press any key to quit"
+Sleep

Task/Identity-matrix/Frink/identity-matrix.frink

@@ -0,0 +1,2 @@
+n = parseInt[input["Enter matrix dimension as an integer: "]]
+println[formatMatrix[makeArray[[n, n], {|a,b| a==b ? 1 : 0}]]]

Task/Identity-matrix/FunL/identity-matrix.funl

@@ -0,0 +1,3 @@
+def identity( n ) = vector( n, n, \r, c -> if r == c then 1 else 0 )
+
+println( identity(3) )

Task/Identity-matrix/FutureBasic/identity-matrix.basic

@@ -0,0 +1,24 @@
+include "NSLog.incl"
+
+local fn IdentityMatrix( n as NSInteger ) as CFStringRef
+NSInteger i, j
+CFMutableArrayRef tempArr = fn MutableArrayWithCapacity( n )
+CFMutableStringRef mutStr = fn MutableStringWithCapacity( 0 )
+
+for i = 0 to n - 1
+MutableArrayRemoveAllObjects( tempArr )
+for j = 0 to n - 1
+MutableArrayInsertObjectAtIndex( tempArr, @"0", j )
+next
+MutableArrayReplaceObjectAtIndex( tempArr, @"1", i )
+MutableStringAppendString( mutStr, fn ArrayComponentsJoinedByString( tempArr, @" " ) )
+MutableStringAppendString( mutStr, @"\n" )
+next
+end fn = fn StringWithString( mutStr )
+
+NSLog( @"3:\n%@", fn IdentityMatrix( 3 ) )
+NSLog( @"5:\n%@", fn IdentityMatrix( 5 ) )
+NSLog( @"7:\n%@", fn IdentityMatrix( 7 ) )
+NSLog( @"9:\n%@", fn IdentityMatrix( 9 ) )
+
+HandleEvents

Task/Identity-matrix/GAP/identity-matrix.gap

@@ -0,0 +1,5 @@
+# Built-in
+IdentityMat(3);
+
+# One can also specify the base ring
+IdentityMat(3, Integers mod 10);

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

@@ -0,0 +1,19 @@
+package main
+
+import (
+    "fmt"
+
+    "gonum.org/v1/gonum/mat"
+)
+
+func eye(n int) *mat.Dense {
+    m := mat.NewDense(n, n, nil)
+    for i := 0; i < n; i++ {
+        m.Set(i, i, 1)
+    }
+    return m
+}
+
+func main() {
+    fmt.Println(mat.Formatted(eye(3)))
+}

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

@@ -0,0 +1,11 @@
+package main
+
+import (
+    "fmt"
+
+    mat "github.com/skelterjohn/go.matrix"
+)
+
+func main() {
+    fmt.Println(mat.Eye(3))
+}

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

@@ -0,0 +1,17 @@
+package main
+
+import "fmt"
+
+func main() {
+    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/Groovy/identity-matrix-1.groovy

@@ -0,0 +1,3 @@
+def makeIdentityMatrix = { n ->
+    (0..<n).collect { i -> (0..<n).collect { j -> (i == j) ? 1 : 0 } }
+}

Task/Identity-matrix/Groovy/identity-matrix-2.groovy

@@ -0,0 +1,5 @@
+(2..6).each { order ->
+    def iMatrix = makeIdentityMatrix(order)
+    iMatrix.each { println it }
+    println()
+}

Task/Identity-matrix/Haskell/identity-matrix-1.hs

@@ -0,0 +1 @@
+matI n = [ [fromEnum $ i == j | i <- [1..n]] | j <- [1..n]]

Task/Identity-matrix/Haskell/identity-matrix-2.hs

@@ -0,0 +1,2 @@
+showMat :: [[Int]] -> String
+showMat = unlines . map (unwords . map show)

Task/Identity-matrix/Haskell/identity-matrix-3.hs

@@ -0,0 +1,10 @@
+*Main> putStr $ showMat $ matId 9
+1 0 0 0 0 0 0 0 0
+0 1 0 0 0 0 0 0 0
+0 0 1 0 0 0 0 0 0
+0 0 0 1 0 0 0 0 0
+0 0 0 0 1 0 0 0 0
+0 0 0 0 0 1 0 0 0
+0 0 0 0 0 0 1 0 0
+0 0 0 0 0 0 0 1 0
+0 0 0 0 0 0 0 0 1

Task/Identity-matrix/Haskell/identity-matrix-4.hs

@@ -0,0 +1,4 @@
+idMatrix :: Int -> [[Int]]
+idMatrix n =
+  let xs = [1 .. n]
+  in xs >>= \x -> [xs >>= \y -> [fromEnum (x == y)]]

Task/Identity-matrix/Haskell/identity-matrix-5.hs

@@ -0,0 +1,7 @@
+idMatrix :: Int -> [[Int]]
+idMatrix n =
+  let xs = [1 .. n]
+  in (\x -> fromEnum . (x ==) <$> xs) <$> xs
+
+main :: IO ()
+main = (putStr . unlines) $ unwords . fmap show <$> idMatrix 5

Task/Identity-matrix/IS-BASIC/identity-matrix.basic

@@ -0,0 +1,21 @@
+100 PROGRAM "Identity.bas"
+110 INPUT PROMPT "Enter size of matrix: ":N
+120 NUMERIC A(1 TO N,1 TO N)
+130 CALL INIT(A)
+140 CALL WRITE(A)
+150 DEF INIT(REF T)
+160   FOR I=LBOUND(T,1) TO UBOUND(T,1)
+170     FOR J=LBOUND(T,2) TO UBOUND(T,2)
+180       LET T(I,J)=0
+190     NEXT
+200     LET T(I,I)=1
+210   NEXT
+220 END DEF
+230 DEF WRITE(REF T)
+240   FOR I=LBOUND(T,1) TO UBOUND(T,1)
+250     FOR J=LBOUND(T,2) TO UBOUND(T,2)
+260       PRINT T(I,J);
+270     NEXT
+280     PRINT
+290   NEXT
+300 END DEF

Task/Identity-matrix/Icon/identity-matrix.icon

@@ -0,0 +1,6 @@
+link matrix
+procedure main(argv)
+    if not (integer(argv[1]) > 0) then stop("Argument must be a positive integer.")
+    matrix1 := identity_matrix(argv[1], argv[1])
+    write_matrix(&output,matrix1)
+end

Task/Identity-matrix/J/identity-matrix.j

@@ -0,0 +1,12 @@
+   = i. 4          NB. create an Identity matrix of size 4
+1 0 0 0
+0 1 0 0
+0 0 1 0
+0 0 0 1
+   makeI=: =@i.    NB. define as a verb with a user-defined name
+   makeI 5         NB. create an Identity matrix of size 5
+1 0 0 0 0
+0 1 0 0 0
+0 0 1 0 0
+0 0 0 1 0
+0 0 0 0 1

Task/Identity-matrix/Java/identity-matrix.java

@@ -0,0 +1,13 @@
+public class PrintIdentityMatrix {
+
+    public static void main(String[] args) {
+        int n = 5;
+        int[][] array = new int[n][n];
+
+        IntStream.range(0, n).forEach(i -> array[i][i] = 1);
+
+        Arrays.stream(array)
+                .map((int[] a) -> Arrays.toString(a))
+                .forEach(System.out::println);
+    }
+}

Task/Identity-matrix/JavaScript/identity-matrix-1.js

@@ -0,0 +1,8 @@
+function idMatrix(n) {
+    return Array.apply(null, new Array(n))
+        .map(function (x, i, xs) {
+            return xs.map(function (_, k) {
+                return i === k ? 1 : 0;
+            })
+        });
+}

Task/Identity-matrix/JavaScript/identity-matrix-2.js

@@ -0,0 +1,16 @@
+(() => {
+
+    // identityMatrix :: Int -> [[Int]]
+    const identityMatrix = n =>
+        Array.from({
+            length: n
+        }, (_, i) => Array.from({
+            length: n
+        }, (_, j) => i !== j ? 0 : 1));
+
+
+    // ----------------------- TEST ------------------------
+    return identityMatrix(5)
+        .map(JSON.stringify)
+        .join('\n');
+})();

Task/Identity-matrix/Jq/identity-matrix-1.jq

@@ -0,0 +1,3 @@
+def identity(n):
+  [range(0;n) | 0] as $row
+  | reduce range(0;n) as $i ([]; . + [ $row | .[$i] = 1 ] );

Task/Identity-matrix/Jq/identity-matrix-2.jq

@@ -0,0 +1 @@
+identity(4)

Task/Identity-matrix/Jq/identity-matrix-3.jq

@@ -0,0 +1,3 @@
+def identity(n):
+  reduce range(0;n) as $i
+    (0 | matrix(n;n); .[$i][$i] = 1);

Task/Identity-matrix/Jsish/identity-matrix.jsish

@@ -0,0 +1,33 @@
+/* Identity matrix, in Jsish */
+function identityMatrix(n) {
+    var mat = new Array(n).fill(0);
+    for (var r in mat) {
+        mat[r] = new Array(n).fill(0);
+        mat[r][r] = 1;
+    }
+    return mat;
+}
+
+provide('identityMatrix', 1);
+
+if (Interp.conf('unitTest')) {
+;    identityMatrix(0);
+;    identityMatrix(1);
+;    identityMatrix(2);
+;    identityMatrix(3);
+    var mat = identityMatrix(4);
+    for (var r in mat) puts(mat[r]);
+}
+
+/*
+=!EXPECTSTART!=
+identityMatrix(0) ==> []
+identityMatrix(1) ==> [ [ 1 ] ]
+identityMatrix(2) ==> [ [ 1, 0 ], [ 0, 1 ] ]
+identityMatrix(3) ==> [ [ 1, 0, 0 ], [ 0, 1, 0 ], [ 0, 0, 1 ] ]
+[ 1, 0, 0, 0 ]
+[ 0, 1, 0, 0 ]
+[ 0, 0, 1, 0 ]
+[ 0, 0, 0, 1 ]
+=!EXPECTEND!=
+*/

Task/Identity-matrix/Julia/identity-matrix-1.julia

@@ -0,0 +1,2 @@
+using LinearAlgebra
+unitfloat64matrix = 1.0I

Task/Identity-matrix/Julia/identity-matrix-2.julia

@@ -0,0 +1,3 @@
+using LinearAlgebra
+diagI3 = 1.0I(3)
+fullI3 = collect(diagI3)

Task/Identity-matrix/Julia/identity-matrix-3.julia

@@ -0,0 +1,5 @@
+using LinearAlgebra
+fullI3 = Matrix{Float64}(I, 3, 3)
+fullI3 = Array{Float64}(I, 3, 3)
+fullI3 = Array{Float64,2}(I, 3, 3)
+fullI3 = zeros(3,3) + I

Task/Identity-matrix/K/identity-matrix.k

@@ -0,0 +1,11 @@
+  =4
+(1 0 0 0
+ 0 1 0 0
+ 0 0 1 0
+ 0 0 0 1)
+  =5
+(1 0 0 0 0
+ 0 1 0 0 0
+ 0 0 1 0 0
+ 0 0 0 1 0
+ 0 0 0 0 1)

Task/Identity-matrix/Kotlin/identity-matrix.kotlin

@@ -0,0 +1,17 @@
+// version 1.0.6
+
+fun main(args: Array<String>) {
+    print("Enter size of matrix : ")
+    val n = readLine()!!.toInt()
+    println()
+    val identity = Array(n) { IntArray(n) } // create n x n matrix of integers
+
+    // enter 1s in diagonal elements
+    for(i in 0 until n) identity[i][i] = 1
+
+    // print identity matrix if n <= 40
+    if (n <= 40)
+        for (i in 0 until n) println(identity[i].joinToString(" "))
+    else
+        println("Matrix is too big to display on 80 column console")
+}

Task/Identity-matrix/LFE/identity-matrix-1.lfe

@@ -0,0 +1,8 @@
+(defun identity
+  ((`(,m ,n))
+   (identity m n))
+  ((m)
+   (identity m m)))
+
+(defun identity (m n)
+  (lists:duplicate m (lists:duplicate n 1)))

Task/Identity-matrix/LFE/identity-matrix-2.lfe

@@ -0,0 +1,6 @@
+> (identity 3)
+((1 1 1) (1 1 1) (1 1 1))
+> (identity 3 3)
+((1 1 1) (1 1 1) (1 1 1))
+> (identity '(3 3))
+((1 1 1) (1 1 1) (1 1 1))

Task/Identity-matrix/LSL/identity-matrix.lsl

@@ -0,0 +1,19 @@
+default {
+	state_entry() {
+		llListen(PUBLIC_CHANNEL, "", llGetOwner(), "");
+		llOwnerSay("Please Enter a Dimension for an Identity Matrix.");
+	}
+	listen(integer iChannel, string sName, key kId, string sMessage) {
+		llOwnerSay("You entered "+sMessage+".");
+		list lMatrix = [];
+		integer x = 0;
+		integer n = (integer)sMessage;
+		for(x=0 ; x<n*n ; x++) {
+			lMatrix += [(integer)(((x+1)%(n+1))==1)];
+		}
+		//llOwnerSay("["+llList2CSV(lMatrix)+"]");
+		for(x=0 ; x<n ; x++) {
+			llOwnerSay("["+llList2CSV(llList2ListStrided(lMatrix, x*n, (x+1)*n-1, 1))+"]");
+		}
+	}
+}