Re: Help ! complex permutations

*To*: mathgroup at smc.vnet.net*Subject*: [mg7045] Re: [mg6965] Help ! complex permutations*From*: "w.meeussen" <w.meeussen.vdmcc at vandemoortele.be>*Date*: Sat, 3 May 1997 22:04:39 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

At 22:25 30-04-97 -0400, Robert Perkins wrote: >I need to derive an algorithm, formula, which gives all the >possiblities, combinations, for any 'n' out of 'm' with the proviso >that any member of 'm' can be used multiple times and the selection >sequence is significant. > >Taking a trivial example if the input list 'm' is > > {a,b} > >the output list 'n' for any 2 gives > > {a,a},{a,b},{b,a},{b,b} > >For an output sequence of 3 from the same input list would give > > {a,a,a},{a,a,b},{a,b,b},{b,a,b},{b,b,a},{b,b,b} > >Life gets interesting for larger input sequences and ever larger >output selections. How about the input list containing 10 members and >the output list containing 20 members with the above rules applying? > >Can anyone point me in the right direction? A reference, clue or even >an algorithm would be very welcome ;) > >TIA > >Robert_p > > > > look at Outer[List,{a,b},{a,b},{a,b}] Dr. Wouter L. J. MEEUSSEN eu000949 at pophost.eunet.be w.meeussen.vdmcc at vandemoortele.be