MakeRandomFormulas

 [Formulas]=MakeRandomFormulas(n,m,c) 
 MakeVarDepFormulas: Creates a set of formulas (one correspond to each objective). Clauses are uniformly randomly selected. 
 INPUT
 n: Number of variables
 m: Number of formulas (objectives)
 c: Number of clauses in each formula 
 OUTPUT
 Formulas: An array of matrices, each matrix has a row for each clause,
           In the row, first the variables involved are shown, then
           whether they are negated (0 value) or not (1 value)
 EXAMPLE
  [Formulas] = MakeRandomFormulas(20,10,20) 

 Last version 8/26/2008. Roberto Santana (roberto.santana@ehu.es)

0001 function[Formulas]=MakeRandomFormulas(n,m,c) 
0002 % [Formulas]=MakeRandomFormulas(n,m,c)
0003 % MakeVarDepFormulas: Creates a set of formulas (one correspond to each objective). Clauses are uniformly randomly selected.
0004 % INPUT
0005 % n: Number of variables
0006 % m: Number of formulas (objectives)
0007 % c: Number of clauses in each formula
0008 % OUTPUT
0009 % Formulas: An array of matrices, each matrix has a row for each clause,
0010 %           In the row, first the variables involved are shown, then
0011 %           whether they are negated (0 value) or not (1 value)
0012 % EXAMPLE
0013 %  [Formulas] = MakeRandomFormulas(20,10,20)
0014 %
0015 % Last version 8/26/2008. Roberto Santana (roberto.santana@ehu.es)
0016 
0017 triples = nchoosek([1:n],3);
0018 ntriples = size(triples,1);
0019 
0020  val = ones(ntriples,1);
0021 
0022  matrix = zeros(n,n);
0023  val = cumsum(val/sum(val));
0024 
0025 
0026  
0027  for i=1:m
0028     Index = sus(c,val);
0029   
0030    for j=1:c
0031      Formulas{i,j} = [triples(Index(j),:),fix(2*rand(1,3))];
0032      matrix(triples(Index(j),1),triples(Index(j),2)) = matrix(triples(Index(j),1),triples(Index(j),2)) + 1;
0033      matrix(triples(Index(j),1),triples(Index(j),3)) = matrix(triples(Index(j),1),triples(Index(j),3)) + 1;
0034      matrix(triples(Index(j),2),triples(Index(j),3)) = matrix(triples(Index(j),2),triples(Index(j),3)) + 1;
0035      matrix(triples(Index(j),2),triples(Index(j),1)) = matrix(triples(Index(j),2),triples(Index(j),1)) + 1;
0036      matrix(triples(Index(j),3),triples(Index(j),1)) = matrix(triples(Index(j),3),triples(Index(j),1)) + 1;
0037      matrix(triples(Index(j),3),triples(Index(j),2)) = matrix(triples(Index(j),3),triples(Index(j),2)) + 1;
0038    end 
0039  end
0040  
0041  %matrix
0042  %sum(matrix(1:10,1:10))
0043  %sum(matrix(11:20,11:20))