Talk:Permutations with repetitions

Mathematica solution incorrect?

The task description says combination must be produced one at a time. The Mathematica solution uses Tuples, which return a list of all permutations at once. Is this a correct solution? --Soegaard (talk) 14:16, 21 May 2013 (UTC)

REXX implementation limits

Most REXX interpreters have implementation limits on the length of a REXX clause.

For Regina REXX, it depends on the release level.

For Regina REXX 3.3,   3.4,   3.5, REXX gives a SYNTAX error:

Error"C:\xxxxxx.REX", line 29: [Clause >]

For Regina REXX 3.6,   3.7, REXX "crashes" somewhere less than a statement length of 1932,
I haven't pursued this to find the exact byte count.

{By crashing, I mean Microsoft Windows displays a small error "window":

Regina Rexx Launcher (x86) has encountered a problem

and needs to close.   We are sorry for the inconvenience.

(more boilerplate follows).

For what's it worth, I believe REXX should raise the SYNTAX condition.

[The reason I mention the older versions of Regina REXX is that Regina REXX
virtual memory for those REXX programs which use a lot of stemmed variables (possibly a
memory leak), so the use of the older Regina release is forced in lieu of a fix.

For PC/REXX and Personal REXX, it depends on what the RXISA (SET environmental variable).
These :

Error:\xxxxxx.REX" Control stack full

Memory full: symbol

Error:\xxxxxx.REX: Machine resources exhausted

somewhere between.

It should be noted that most people use the maximum for the RXISA   (which is.

As far as I can tell, Rno (real) limitation for the length of an INTERPRET instruction,
and that is probably true of CMS REXX and TSO REXX   (it's been too long since I used those
.

-- Gerard Schildberger (talk) 20:2013 (UTC)

---

another variant of the

This REXX version:

• simplifies many statements
• minimizes the length of the INTERPRET statement
• eliminates the SELECT statements
• eliminates a DO loop
• uses both kinds of quotes strings to make it easier to peruse
• moves a couple of statements out of the INTERPRET clause
• uses a positive (logic) instead of a negative IF statement
• eliminates an extra   ;   (semicolon) from the INTERPRET clause
• eliminates the need for counting the permutations

If any of these improvements could/would be of use, that's fine.   I plan to delete this entry in a couple of weeks. -- Gerard Schildberger (talk) 04:2013 (UTC) <lang rexx>/*REXX*/ parse arg n m s names if n= then n== then m=(s,'N') then s=left(,s)

       do k=names=   then e.k=k
                     else parse var names e.k names
       end   /*k*/

a=

                   do i=;   a=a'do d'i"=;";   end  /*i*/

a=a'z=e.d1'

                   do j=;   a=a"||s||e.d"j;         end  /*j*/

a=a';say z'copies(";end",m) if m==; say ', a "null".'; exit; end interpret a say n**m 'permutations'</lang>