  3D picture of the coronal magnetic field remains an outstanding problem in
solar physics, particularly, in active regions. Nonlinear force-free field
reconstructions that employ routinely available full-disk photospheric vector
magnetograms represent state-of-the-art coronal magnetic field modeling. Such
reconstructions, however, suffer from an inconsistency between a force-free
coronal magnetic field and non-force-free photospheric boundary condition, from
which the coronal reconstruction is performed. In this study we focus on
integrating the additional chromospheric and / or coronal magnetic field data
with the vector photospheric magnetograms with the goal of improving the
reliability of the magnetic field reconstructions. We develop a corresponding
modification of the available optimization codes described in Fleishman et al.
(2017) and test their performance using a full-fledged MHD model obtained from
the Bifrost code by performing a `voxel-by-voxel' comparison between the
reconstructed and the model magnetic fields. We demonstrate that adding even an
incomplete set of chromospheric magnetic field data can measurably improve the
reconstruction of the coronal magnetic field, greatly improve reconstructions
of the magnetic connectivity and of the coronal electric current.
