Data commit

Task/Identity-matrix/REXX/identity-matrix-1.rexx

@@ -0,0 +1,30 @@
+/*REXX program  creates and displays any sized  identity matrix  (centered, with title).*/
+           do k=3  to 6                          /* [↓]  build and display a sq. matrix.*/
+           call ident_mat  k                     /*build & display a KxK square matrix. */
+           end   /*k*/                           /* [↑]  use general─purpose display sub*/
+exit                                             /*stick a fork in it,  we're all done. */
+/*──────────────────────────────────────────────────────────────────────────────────────*/
+ident_mat: procedure;  parse arg n; $=
+              do    r=1  for n                   /*build identity matrix, by row and col*/
+                 do c=1  for n;     $= $ (r==c)  /*append  zero  or  one  (if on diag). */
+                 end   /*c*/
+              end      /*r*/
+           call showMat  'identity matrix of size'   n,   $
+           return
+/*──────────────────────────────────────────────────────────────────────────────────────*/
+showMat: procedure; parse arg hdr,x;  #=words(x) /*#  is the number of matrix elements. */
+         dp= 0                                   /*DP:  max width of decimal fractions. */
+         w= 0                                    /*W:   max width of integer part.      */
+                 do n=1  until n*n>=#;  _= word(x,n)      /*determine the matrix order. */
+                 parse var _ y '.' f;   w= max(w, length(y));      dp= max(dp, length(f) )
+                 end   /*n*/                     /* [↑]  idiomatically find the widths. */
+         w= w +1
+         say;  say center(hdr, max(length(hdr)+8, (w+1)*#%n), '─');  say
+         #= 0                                                            /*#: element #.*/
+                 do   row=1  for n;     _= left('', n+w)                 /*indentation. */
+                   do col=1  for n;     #= # + 1                         /*bump element.*/
+                   _=_ right(format(word(x, #), , dp)/1, w)
+                   end   /*col*/                 /* [↑]  division by unity normalizes #.*/
+                 say _                           /*display a single line of the matrix. */
+                 end     /*row*/
+         return

Task/Identity-matrix/REXX/identity-matrix-2.rexx

@@ -0,0 +1,16 @@
+/* REXX ***************************************************************
+* show identity matrix of size n
+* I consider m.i.j to represent the matrix (not needed for showing)
+* 06.07.2012 Walter Pachl
+**********************************************************************/
+Parse Arg n
+Say 'Identity Matrix of size' n '(m.i.j IS the Matrix)'
+m.=0
+Do i=1 To n
+  ol=''
+  Do j=1 To n
+    m.i.j=(i=j)
+    ol=ol''format(m.i.j,2) /* or ol=ol (i=j)                         */
+    End
+  Say ol
+  End

Task/Identity-matrix/REXX/identity-matrix-3.rexx

@@ -0,0 +1,3 @@
+m.=0
+m.0=1000 /* the matrix' size */
+m.4.17.333='Walter'