Description of mtimes

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mtimes

PURPOSE

mtimes(p,q) --- p*q is the meet of the partitions p and q

SYNOPSIS

function r = mtimes(p,q)

DESCRIPTION

 mtimes(p,q) --- p*q is the meet of the partitions p and q

CROSS-REFERENCE INFORMATION

This function calls:

• np np(p) --- number of parts in the partition p
• nv nv(p) --- number of vertices (elements) of a partition

This function is called by:

SOURCE CODE

0001 function r = mtimes(p,q)
0002 % mtimes(p,q) --- p*q is the meet of the partitions p and q
0003 
0004 n1 = nv(p);
0005 n2 = nv(q);
0006 
0007 if n1 ~= n2
0008     error('* only defined for partitions on the same ground set')
0009 end
0010 
0011 m1 = np(p);
0012 m2 = np(q);
0013 
0014 mat = sparse(0,0);
0015 
0016 for i=1:m1
0017     for j=1:m2
0018         a = p.array(i,:) & q.array(j,:);
0019         if sum(a) > 0
0020             mat = [mat;a];
0021         end
0022     end
0023 end
0024 
0025 mat = sortrows(mat);
0026 mat = unique(mat,'rows');
0027 r.array = mat;
0028 
0029 r = class(r,'partition');

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