MINCONNECT

MINimal CONNECTivity (adjacency) matrix for (X,Y) points on a plane, and/or graph of connections.

Needs CLINE.

Applications: graph theory, optimal traffic, astronomy (e.g. if you
want to see a tree of connected stars selected according to certain bounds on distance and/or magnitude etc).

The connections obey following optimality condition:
breaking any connection divides all points into two groups such that
the broken connection corresponds to the shortest distance between
the two groups.

Algorithm: a cluster of already connected points grows by adding
the nearest of resting points

Call:
[M,ZZ]=minconnect(X,Y[,colspec]); (brackets="optional colspec")
[M,ZZ]=minconnect(X[,colspec],Y); [M,ZZ]=minconnect(XY[,colspec]);
(XY means [X(:), Y(:)] or X+1i*Y) [M,ZZ]=minconnect([colspec,]XY);

Input:
X = vector of abscissas
Y = vector of ordinates
colspec: color/marker/line
specification as in CLINE:
if set, connection tree is shown
X,Y and colspec (or XY and colspec) may be entered in any
sequence, but X should precede Y

Output:
M = minimal connectivity (adjacency) matrix: M(i,j)=true,
if i<j and point number i is connected with point number j
ZZ=(complex) start and finish of all connections