42 lines
		
	
	
		
			580 B
		
	
	
	
		
			Matlab
		
	
	
			
		
		
	
	
			42 lines
		
	
	
		
			580 B
		
	
	
	
		
			Matlab
		
	
	
| % frank05: show right pre-conditioning
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| % first run frank03 or other script to generate graph, config, and ordering
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| 
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| % linearize the non-linear factor graph
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| tic
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| LFG = graph.linearize_(config);
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| toc
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| tic
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| ijs = LFG.sparse(ordering);
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| A = sparse(ijs(1,:),ijs(2,:),ijs(3,:)); 
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| toc
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| figure(1)
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| spy(A);
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| 
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| % isolate the spanning tree part
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| A1=A(1:3*nnz(tree),:);
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| % add prior
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| figure(2)
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| spy(A1)
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| 
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| % calculate R1
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| tic
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| R1 = qr(A1,0);
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| toc
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| figure(3)
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| spy(R1)
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| 
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| % calculate R1
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| tic
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| R1 = chol(A1'*A1);
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| toc
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| figure(3)
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| spy(R1)
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| 
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| % calculate the entire R factor (expensive)
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| tic
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| R = qr(A,0);
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| toc
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| figure(4)
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| spy(R)
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| 
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