Questions on the use of Mathematica in combinatorics, including the Combinatorica add-on package.
1
vote
2answers
64 views
Create simple table with function of column values
I just want to create a simple table:
Three input columns, one output column
Call the inputs {x,y,z}, each can take values ...
4
votes
1answer
93 views
Random filling of L-length line with l-length segments
I have discrete L-length line filled randomly with 2-length segments so its cover line with gaps 0 or 1. So we can describe cover configuration as sequence of gaps such as {0,0,1,0,1}. How I can ...
3
votes
3answers
105 views
Finding specific compositions of an Integer
I need to find all compositions of an integer L wherein all parts do not exсeed l and parts less then l cound not be neighbor. Here is my code
...
3
votes
6answers
172 views
Concise way to generate multiset lists
I wrote the following to generate a multiset with the same number of items over a fixed range:
ConstantArray[#, 3]& /@ Range[9] // Flatten
...
2
votes
4answers
163 views
find the number of integral solutions a+b+c+d+e+f = 18 [duplicate]
Find the number of integral solutions of
a + b + c + d + e + f = 18
where a, b, c, d, e, f are elements of the range ...
5
votes
1answer
140 views
All possible topological orderings of a graph
TopologicalSort[] returns one of many unique orderings.
From wikipedia:
if a topological sort does not form a Hamiltonian path, the DAG will have two or ...
0
votes
1answer
57 views
how to permute bit strings and manipulate their elements
I want to write a function(has 2 paremeter, n=range,k=number of 1 digits) which finds all probable combinatorics of arbitrary bit strings and evaluate sum of tensor ...
5
votes
4answers
123 views
How can I generate permutations of bit strings with repetition?
How can I write a function which has two parameters and it should generate combination of arbitrary range bits, for example: function[n, k], with ...
3
votes
0answers
62 views
Listing all combinations produced by picking one element from each of several sets [duplicate]
I have a problem like this, I am given the following sets {a,b,c}, {d,e,f}, {h,i,j}. I want to pick one element from each set, and output a list of all the ...
5
votes
2answers
228 views
Sierpinski carpet with GraphData
Is this graph in the list among the so-called "standard" structures used in GraphData? However, I have not found, yet, anything like "Carpet" or "Sponge" in the ...
-1
votes
1answer
50 views
Permutation of arguments of product of functions
Given a function, g, which is symmetric in its argument, g(a,b)=g(b,a), consider the product g(a,b)*g(c,d)*g(e,f). I would like to get all the permutations of this product with respect to the ...
0
votes
0answers
41 views
Identify columns of a huge matrix just polynomially many rows chosen at random
I am interested in the following problem in combinatorics $\Cap$ Probability. Let $\lambda \in \mathbb{N}$ be a parameter. Consider a matrix of $2^\lambda$ rows and $2^\lambda$ columns. Each column ...
0
votes
0answers
83 views
Pearl's Message Passing Algorithm
Has anyone tried to implement the Message Passing algorithm using Mathematica's Graph/Combinatorica features?
4
votes
4answers
253 views
Listing matrices up to symmetry
I am interested in the equivalence relation on N x N binary matrices, in which two matrices are equivalent if one can be obtained by rotating/reflecting the other. I would like to obtain a list
...
0
votes
0answers
102 views
My algorithm produces too many permutations
Imagine the following problem. A population of size $n$ consists of $i$ men and $n-i$ women. The population goes to the casino. Call $g_m$ ,$g_w$ the amount of money won by men and women respectively. ...
