  We propose a scheme comprising an array of anisotropic optical waveguides,
embedded in a gas of cold atoms, which can be tuned from a Hermitian to an
odd-PT -- symmetric configuration through the manipulation of control and
assistant laser fields. We show that the system can be controlled by tuning
intra -- and inter-cell coupling coefficients, enabling the creation of
topologically distinct phases and linear topological edge states. The waveguide
array, characterized by a quadrimer primitive cell, allows for implementing
transitions between Hermitian and odd-PT -symmetric configurations, broken and
unbroken PT -symmetric phases, topologically trivial and nontrivial phases, as
well as transitions between linear and nonlinear regimes. The introduced scheme
generalizes the Rice-Mele Hamiltonian for a nonlinear non-Hermitian quadrimer
array featuring odd-PT symmetry and makes accessible unique phenomena and
functionalities that emerge from the interplay of non-Hermiticity, topology,
and nonlinearity. We also show that in the presence of nonlinearity the system
sustains nonlinear topological edge states bifurcating from the linear
topological edge states and the modes without linear limit. Each nonlinear mode
represents a doublet of odd-PT -conjugate states. In the broken PT phase, the
nonlinear edge states may be effectively stabilized when an additional
absorption is introduced into the system.
