etree

Purpose

Elimination tree of a matrix.

Synopsis

p = etree(A)
p = etree(A,'col')
[p,q] = etree(...)

Description

p = etree(A) returns an elimination tree for the square symmetric matrix whose upper triangle is that of A. p(j) is the parent of column j in the tree, or 0 if j is a root.

p = etree(A,'col') returns the elimination tree of A'*A.

[p,q] = etree(...) returns a postorder permutation q on the tree.

Examples

etreeplot(sprandsym(50, 0.1))

References

[1] John R. Gilbert, Cleve Moler and Robert Schreiber, "Sparse Matrices in MATLAB: Design and Implementation," SIAM Journal on Matrix Analysis and Applications 13, pp. 333-356, Jan. 1992.