Re: Integer Solutions

• To: mathgroup at smc.vnet.net
• Subject: [mg6530] Re: [mg6494] Integer Solutions
• From: Robert Pratt <rpratt at math.unc.edu>
• Date: Mon, 31 Mar 1997 23:01:31 -0500 (EST)
• Sender: owner-wri-mathgroup at wolfram.com

```If all your problems are of the form x1+x2+...+xk=n, xi>0 for all i, then
you can use the built-in command Compositions in the standard package
DiscreteMath`Combinatorica`.

In[1]:= Needs["DiscreteMath`Combinatorica`"]

In[2]:= ?Compositions
Compositions[n,k] returns a list of all compositions of integer n into k
parts.

In[3]:= Compositions[3,2]

Out[3]= {{0, 3}, {1, 2}, {2, 1}, {3, 0}}

Rob Pratt
Department of Mathematics
The University of North Carolina at Chapel Hill
CB# 3250, 331 Phillips Hall
Chapel Hill, NC  27599-3250

rpratt at math.unc.edu

On Thu, 27 Mar 1997, Jason Constandinidis wrote:

> Does anybody know how mmka can give _ALL_ solutions that are Integers??
> I want for example to solve the equation x+y=3 x>0 y>0 and get
> {{3,0}, {2,1}, {1,2}, {0,3}}
> Jason.
>
>

```

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