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>