Description of merge

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merge

PURPOSE

merge(p,x,y) --- form a partition from p by combining x and y's parts.

SYNOPSIS

function q = merge(p,x,y)

DESCRIPTION

 merge(p,x,y) --- form a partition from p by combining x and y's parts.
 If x or y are out of range, p is returned.

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:

• plus plus --- p+q is the join of p and q

SOURCE CODE

0001 function q = merge(p,x,y)
0002 % merge(p,x,y) --- form a partition from p by combining x and y's parts.
0003 % If x or y are out of range, p is returned.
0004 
0005 q = p;
0006 n = nv(p);
0007 
0008 if (x<1) | (x>n) | (y<1) | (y>n) | (x==y)
0009     return
0010 end
0011 
0012 rx = find(p.array(:,x));
0013 ry = find(p.array(:,y));
0014 
0015 if rx == ry
0016     return
0017 end
0018 
0019 % merge row ry into row rx
0020 q.array(rx,:) = q.array(rx,:) | q.array(ry,:);
0021 
0022 % remove row ry
0023 
0024 idx = [1:ry-1,ry+1:np(p)];
0025 q.array = q.array(idx,:);
0026 q.array = sortrows(q.array);

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