Matlab Programs developed by Li and his colleagues

Generalized Numerical Ranges

the c-numerical range of matrices,
the q-numerical range of a 3-by-3 normal matrix,
the q-numerical range of a general complex matrix,
the joint numerical range of 3 hermitian matrices,
the krein space numerical range.

Central Groupoids and Centeral Digraphs

Useful references are:
F. Curtis and D. Pragel, Central groupoids, central digraphs, and zero-one matrices A satisfying A^2 = J, REU report, College of William and Mary, 2002. pdf file.
F. Curtis, J. Drew, C.K. Li and D. Pragel, Central groupoids, central digraphs, and zero-one matrices A satisfying A^2 = J. pdf file.
F. Curtis, J. Drew, C.K. Li and D. Pragel, Computer Programs and Examples in the study of Central groupoids, central digraphs, and zero-one matrices A satisfying A^2 = J. pdf file.

MakeStandard(k) : creating the adjancy matrix of the standard central digraph.
MakeSwitch(p,q;r,s,A) : performing the switch [p,q;r,s] on the adjancency matrix A of a central digraph.
AllRanks(k) : creating adjacency matrices of central digraphs of all possible ranks.
DRM(A) : applying a permutation similarity to A to get a matrix with decreasing row multiplicity.
PerSim(A,B) : identifying adjacency matrices that correspond to the same central digraphs.