dag.sp                 package:RBGL                 R Documentation

_D_A_G _s_h_o_r_t_e_s_t _p_a_t_h_s _u_s_i_n_g _b_o_o_s_t _C++

_D_e_s_c_r_i_p_t_i_o_n:

     Algorithm for the single-source shortest-paths problem on a
     weighted, directed acyclic graph (DAG)

_U_s_a_g_e:

     dag.sp(g,start=nodes(g)[1])

_A_r_g_u_m_e_n_t_s:

       g: instance of class graph 

   start: source node for start of paths 

_D_e_t_a_i_l_s:

     These functions are interfaces to the Boost graph library C++
     routines for single-source shortest-paths on a weighted directed
     acyclic graph. Choose appropriate shortest-path algorithms
     carefully based on the properties of the input graph.  See
     documentation in Boost Graph Library for more details.

_V_a_l_u_e:

     A list with elements: 

distance: The vector of distances from 'start' to each node of 'g';
          includes 'Inf' when there is no path from 'start'.

  penult: A vector of indices (in 'nodes(g)') of predecessors
          corresponding to each node on the path from that node back to
          'start'. For example, if the element one of this vector has
          value '10', that means that the predecessor of node '1' is
          node '10'. The next predecessor is found by examining
          'penult[10]'.

   start: The start node that was supplied in the call to 'dag.sp'.

_A_u_t_h_o_r(_s):

     Li Long <li.long@isb-sib.ch>

_S_e_e _A_l_s_o:

     'bellman.ford.sp', 'dijkstra.sp', 'johnson.all.pairs.sp',
     'sp.between'

_E_x_a_m_p_l_e_s:

     dd <- fromGXL(file(system.file("XML/conn2.gxl",package="RBGL"), open="r"))
     dag.sp(dd)
     dag.sp(dd,nodes(dd)[2])

