X and y are vectors of coordinates in the unit square at which

to lay out the nodes of the tree to make a nice picture.

Optionally, h is the height of the tree and s is the

number of vertices in the top-level separator.

See also etree, treeplot, etreeplot, symbfact.

Reference page in Help browser

doc treelayout

<treeplot> - Plot picture of tree.

TREEPLOT Plot picture of tree.

TREEPLOT(p) plots a picture of a tree given a row vector of

parent pointers, with p(i) == 0 for a root.

TREEPLOT(P,nodeSpec,edgeSpec) allows optional parameters nodeSpec

and edgeSpec to set the node or edge color, marker, and linestyle.

Use '' to omit one or both.

Example:

treeplot([2 4 2 0 6 4 6])

returns a complete binary tree.

See also etree, treelayout, etreeplot.

Reference page in Help browser

doc treeplot

<etree> - Elimination tree.

ETREE Elimination tree

Finds the elimination tree of A, A'*A, or A*A', and optionaly postorders

the tree. parent(j) is the parent of node j in the tree, or 0 if j is a

root. The symmetric case uses only the upper or lower triangular part of

A (ETREE(A) uses the upper part, and ETREE(A,'lo') uses the lower part).

parent = ETREE(A) finds the elimination tree of A, using TRIU(A)

parent = ETREE(A,'sym') same as ETREE(A)

parent = ETREE(A,'col') finds the elimination tree of A'*A

parent = ETREE(A,'row') finds the elimination tree of A*A'

parent = ETREE(A,'lo') finds the elimination tree of A, using TRIL(A)

[parent,post] = ETREE(...) also returns a postordering of the tree.

If you have a fill-reducing permutation p, you can combine it with an

elimination tree postordering using the following code. Postordering has

no effect on fill-in (except for lu), but it does improve the performance

of the subsequent factorization.

For the symmetric case, suitable for CHOL(A(p,p)):

[parent,post] = ETREE(A(p,p));

p = p(post);

For the column case, suitable for QR(A(:,p)) or LU(A(:,p)):

[parent,post] = ETREE(A(:,p),'col');

p = p(post);

For the row case, suitable for QR(A(p,:)') or CHOL(A(p,:)*A(p,:)'):

[parent,post] = ETREE(A(p,:),'row');

p = p(post);

See also treelayout, treeplot, etreeplot.

Reference page in Help browser

doc etree

<etreeplot> - Plot elimination tree.

ETREEPLOT Plot elimination tree.

ETREEPLOT(A) plots the elimination tree of A (or A+A', if

non-symmetric).

ETREEPLOT(A,nodeSpec,edgespec) allows optional parameters nodeSpec

and edgeSpec to set the node or edge color, marker, and linestyle.

Use '' to omit one or both.

See also treeplot, etree, treelayout.

Reference page in Help browser

doc etreeplot

<gplot> - Plot graph, as in "graph theory".

GPLOT Plot graph, as in "graph theory".

GPLOT(A,xy) plots the graph specified by A and xy. A graph, G, is

a set of nodes numbered from 1 to n, and a set of connections, or

edges, between them.

In order to plot G, two matrices are needed. The adjacency matrix,

A, has a(i,j) nonzero if and only if node i is connected to node

j. The coordinates array, xy, is an n-by-2 matrix with the

position for node i in the i-th row, xy(i,:) = [x(i) y(i)].

GPLOT(A,xy,LineSpec) uses line type and color specified in the

string LineSpec. See PLOT for possibilities.

[X,Y] = GPLOT(A,xy) returns the NaN-punctuated vectors

X and Y without actually generating a plot. These vectors

can be used to generate the plot at a later time if desired. As a

result, the two argument output case is only valid when xy is of type

single or double.

See also spy, treeplot.

Reference page in Help browser

doc gplot