tree ← wgraph ##.wspan from ⍝ Spanning tree for weighted graph ⍺ from ⍵. [wspan] constructs a tree of the lowest-cost paths from the given root to all accessible vertices of the weighted graph. Each item of the vector result, with the exception of the root item (¯1), is the index of the corresponding tree node's parent node. Technical notes: This coding differs slightly from classic breadth-first search, see →bfs←. Examples: aa ⍝ simple weighted graph. ┌───┬─┬───┬───┬─┐ │2 3│3│2 4│1 5│3│ ├───┼─┼───┼───┼─┤ │1 3│1│4 1│1 1│1│ └───┴─┴───┴───┴─┘ aa wspan 1 ⍝ spanning tree for aa from vertex 1. ¯1 1 2 3 4 See also: wGraphs Graphs See also: bfs wpath wcost stpath span Back to: contents Back to: Workspaces