At each level the nodes of a recombining tree are indexed from 1 to n (the number of tree nodes at this level), where 1 denotes the lowermost node and n denotes the uppermost node of the tree. The GetDescendants command returns the list of indices of the descendants of node j at level i of the tree T. This command is related to the GetProbabilities command in-as-much as the descendants returned by GetDescendants and transition probabilities returned by GetProbabilities are ordered correspondingly.

Note that node descendants cannot be set. Instead you can adjust the state space and the transition probabilities to achieve the same approximating tree.

$\mathrm{with}\left(\mathrm{Finance}\right)\:$

$X≔\mathrm{OrnsteinUhlenbeckProcess}\left(0.1\,1.0\,0.03\,0.3\right)$

$X≔\mathrm{\_X0}$

$T≔\mathrm{ShortRateTree}\left(X\,4\,10\right)$

$T≔\mathbf{module}\left(\right)\mathbf{end\; module}$

$\mathrm{TreePlot}\left(T\,\mathrm{thickness}=2\,\mathrm{gridlines}=\mathrm{true}\right)$

$\mathrm{GetDescendants}\left(T\,3\,3\right)$

$\left[3\,4\,5\right]$

$\mathrm{GetProbabilities}\left(T\,3\,3\right)$

$\left[0.1507749899\,0.6655866667\,0.1836383434\right]$

The Finance[GetDescendants] command was introduced in Maple 15.

For more information on Maple 15 changes, see Updates in Maple 15.