1function etree_sample 2% ETREE_SAMPLE construct a sample etree and symbolic factorization 3% 4% Example 5% etree_sample 6% See also: testall 7 8% Copyright 2006-2012, Timothy A. Davis, http://www.suitesparse.com 9 10clf 11 12% desired etree: 13% 1 2 3 4 5 6 7 8 9 10 11 14goal = [6 3 8 6 8 7 9 10 10 11 0] ; 15 16o = 0 ; 17X = 1 ; 18x = 0 ; 19 20A = [ 211 o o o o o o o o o o 22o 2 o o o o o o o o o 23o X 3 o o o o o o o o 24o o o 4 o o o o o o o 25o o o o 5 o o o o o o 26X o o X o 6 o o o o o 27X o o x o x 7 o o o o 28o X x o X o o 8 o o o 29x o o x o X x o 9 o o 30x x X X x X x X x 10 o 31x x X x X x X X x X 11 ] ; 32 33A = A + tril(A,-1)' ; 34disp ('A = ') ; 35disp (A) 36 37[count,h,parent,post,R] = symbfact (A) ; 38L = R' ; 39 40subplot (2,3,1) ; 41spy (A) 42title ('A') ; 43 44subplot (2,3,2) ; 45etreeplot (A) 46title ('etree') ; 47 48% [parent, post] = etree (A) ; 49 50subplot (2,3,3) ; 51spy (L) 52title ('L, not postordered') ; 53 54n = size (A,1) ; 55for k = 1:n 56 fprintf ('parent (%d) = %d goal: %d ok: %d\n', ... 57 k, parent (k), goal (k), goal (k) == parent(k)) ; 58end 59 60 61[count,h,parent2,post2,R] = symbfact (A (post,post)) ; 62L = R' ; 63 64subplot (2,3,5) ; 65spy (A (post,post)) 66title ('A postordered') ; 67 68subplot (2,3,6) ; 69spy (L) 70title ('L postordered') ; 71