  We characterize the equality between ultradifferentiable function classes
defined in terms of abstractly given weight matrices and in terms of the
corresponding matrix of associated weight functions by using new growth
indices. These indices, defined by means of weight sequences and (associated)
weight functions, are extending the notion of O-regular variation to a mixed
setting. Hence we are extending the known comparison results concerning classes
defined in terms of a single weight sequence and of a single weight function
and give also these statements an interpretation expressed in O-regular
variation.
