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Re: generating submultisets with repeated elements

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  • Subject: [mg103681] Re: generating submultisets with repeated elements
  • From: David Bevan <david.bevan at>
  • Date: Fri, 2 Oct 2009 08:23:57 -0400 (EDT)
  • References: <>

I've now tried the following, which avoids generating the extra multisets:







Any suggestions for a better approach?

David %^>

From: David Bevan
Sent: 01 October 2009 18:57
To: mathgroup at
Subject: [mg103681] generating submultisets with repeated elements

I'm new to Mathematica, so if I've missed something obvious, my apologies.

I want a function to generate a list of "submultisets" with up to k elements of a set s, allowing elements from s to be repeated.

The following works, but is very inefficient since each multiset is generated multiple times and then sorted and then repeats deleted:




I assumed there would be a suitable function in the Combinatorica package, but I can't see anything -- which would be a bit odd for a combinatorial package. What have I missed?

Do I need to write my own (perhaps by looking at how KSubsets is implemented) or is there some easy way of generating these multisets?


David %^>

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