Searching Equienergetic Chemical TreesThis research aims to develop insight and algorithms to join the search for graphs with equal energy, regarding some possible definitions on what graph energy is. This research is made on a class of graphs called Chemical Trees, defined to be those which are acyclic and which each vertex has degree at most 4. High-performance code is to be developed, as this research, which is at initial stage (started Feb 2009), goes further.

The first interactive program can be found here. The corresponding C-code (called through a PHP interface) implements a call to CLapack routine

dspev_(computation of eigenvalues of symmetric matrix with packed storage).The second interactive program can be found here. This script implements a search and classify procedure in a data set that we already have stored in a

MySQLdatabase.

Definitions of energy being used:given a graph let be its adjacency matrix, let

eigbe the vector of eigenvalues of a given matrix, and the 1-norm of a vector (sum of absolute values of its components).Define

to be called justenergyof graph .JBC 19/2/2009,13/5/2010