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Diffstat (limited to 'sourcecodes/bnt-master/graph/mk_adj_mat.m')
| -rw-r--r-- | sourcecodes/bnt-master/graph/mk_adj_mat.m | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/sourcecodes/bnt-master/graph/mk_adj_mat.m b/sourcecodes/bnt-master/graph/mk_adj_mat.m new file mode 100644 index 00000000..09f73d4a --- /dev/null +++ b/sourcecodes/bnt-master/graph/mk_adj_mat.m @@ -0,0 +1,36 @@ +function [A, names] = mk_adj_mat(connections, names, topological) +% MK_ADJ_MAT Make a directed adjacency matrix from a list of connections between named nodes. +% +% A = mk_adj_mat(connections, name) +% This is best explaine by an example: +% names = {'WetGrass', 'Sprinkler', 'Cloudy', 'Rain'}; +% connections = {'Cloudy', 'Sprinkler'; 'Cloudy', 'Rain'; 'Sprinkler', 'WetGrass'; 'Rain', 'WetGrass'}; +% adds the arcs C -> S, C -> R, S -> W, R -> W. Node 1 is W, 2 is S, 3 is C, 4 is R. +% +% [A, names] = mk_adj_mat(connections, name, 1) +% The last argument of 1 indicates that we should topologically sort the nodes (parents before children). +% In the example, the numbering becomes: node 1 is C, 2 is R, 3 is S, 4 is W +% and the return value of names gets permuted to {'Cloudy', 'Rain', 'Sprinkler', 'WetGrass'}. +% Note that topological sorting the graph is only possible if it has no directed cycles. + +if nargin < 3, topological = 0; end + +n=length(names); +A=zeros(n); +[nr nc] = size(connections); +for r=1:nr + from = strmatch(connections{r,1}, names, 'exact'); + assert(~isempty(from)); + to = strmatch(connections{r,2}, names, 'exact'); + assert(~isempty(to)); + %fprintf(1, 'from %s %d to %s %d\n', connections{r,1}, from, connections{r,2}, to); + A(from,to) = 1; +end + +if topological + order = topological_sort(A); + A = A(order, order); + names = names(order); +end + + |