bfs                   package:RBGL                   R Documentation

_B_r_e_a_d_t_h _a_n_d _D_e_p_t_h-_f_i_r_s_t _s_e_a_r_c_h

_D_e_s_c_r_i_p_t_i_o_n:

     These functions return information on graph traversal by breadth
     and depth first search using routines from the BOOST library.

_U_s_a_g_e:

     bfs(object, node, checkConn=TRUE)
     dfs(object, node, checkConn=TRUE)

_A_r_g_u_m_e_n_t_s:

  object: instance of class graph from Bioconductor graph class

    node: node name where search starts; defaults to the node in first
          position in the node vector.

checkConn: logical for backwards compatibility; this parameter has no
          effect as of RBGL 1.7.9 and will be removed in future
          versions.

_D_e_t_a_i_l_s:

     These two functions are interfaces to the BOOST graph library
     functions for  breadth first and depth first search. Both methods
     handle unconnected graphs  by applying the algorithms over the
     connected components. 

     Cormen et al note (p 542) that `results of depth-first search may
     depend upon the order in which the vertices are examined ... These
     different visitation orders tend not to cause problems in
     practice, as any DFS result can usually be used effectively, with
     essentially equivalent results'.

_V_a_l_u_e:

     For 'bfs' a vector of node indices in order of BFS visit.

     For 'dfs' a list of two vectors of nodes, with elements 'discover'
      (order of DFS discovery), and 'finish' (order of DFS completion).

_A_u_t_h_o_r(_s):

     VJ Carey <stvjc@channing.harvard.edu>

_R_e_f_e_r_e_n_c_e_s:

     Boost Graph Library ( www.boost.org/libs/graph/doc/index.html )

     The Boost Graph Library: User Guide and Reference Manual; by
     Jeremy G. Siek, Lie-Quan Lee, and Andrew Lumsdaine;
     (Addison-Wesley, Pearson Education Inc., 2002), xxiv+321pp. ISBN
     0-201-72914-8

_E_x_a_m_p_l_e_s:

     con1 <- file(system.file("XML/bfsex.gxl",package="RBGL"), open="r")
     dd <- fromGXL(con1)
     close(con1)

     bfs(dd, "r")
     bfs(dd, "s")

     con2 <- file(system.file("XML/dfsex.gxl",package="RBGL"), open="r")
     dd2 <- fromGXL(con2)
     close(con2)

     dfs(dd2, "u")

