Groups

Groups categorize the problems in Matrix Depot. Group names are symbols, e.g. :symmetric, and can be used as patterns anywhere a pattern is accepted. listgroups returns all defined groups.

Predefined groups

group	meaning
`:all`	all problems in the collection
`:builtin`	locally generated built-in problems
`:user`	user-defined generators, see User Generators
`:local`	`:builtin` and `:user`
`:eigen`	part of the eigensystem is explicitly known
`:graph`	adjacency matrix of a graph
`:illcond`	ill-conditioned for some parameter values
`:inverse`	the inverse is known explicitly
`:orthogonal`	the matrix is orthogonal
`:posdef`	positive definite for some parameter values
`:random`	the matrix has random entries
`:regprob`	test problem for regularization methods
`:sparse`	the matrix is sparse
`:symmetric`	symmetric for some parameter values

listnames(:posdef)

list(14)
cauchy	hilb	kms	minij	oscillate	pei	tridiag
circul	invhilb	lehmer	moler	pascal	poisson	wathen

User-defined groups

setgroup! defines a new group from any pattern, not only from lists of names, and deletegroup! removes it again:

setgroup!(:myfav, ["lehmer", "cauchy", "hilb"])
setgroup!(:spd, :symmetric & :posdef)
mdlist(:myfav)

3-element Vector{String}:
 "cauchy"
 "hilb"
 "lehmer"

deletegroup!(:myfav)
deletegroup!(:spd)