  Magnetic fields are one of the most important drivers of the highly dynamic
processes that occur in the lower solar atmosphere. They span a broad range of
sizes, from large- and intermediate-scale structures such as sunspots, pores
and magnetic knots, down to the smallest magnetic elements observable with
current telescopes. On small scales, magnetic flux tubes are often visible as
Magnetic Bright Points (MBPs). Apart from simple $V/I$ magnetograms, the most
common method to deduce their magnetic properties is the inversion of
spectropolarimetric data. Here we employ the SIR code for that purpose. SIR is
a well-established tool that can derive not only the magnetic field vector and
other atmospheric parameters (e.g., temperature, line-of-sight velocity), but
also their stratifications with height, effectively producing 3-dimensional
models of the lower solar atmosphere. In order to enhance the runtime
performance and the usability of SIR we parallelized the existing code and
standardized the input and output formats. This and other improvements make it
feasible to invert extensive high-resolution data sets within a reasonable
amount of computing time. An evaluation of the speedup of the parallel SIR code
shows a substantial improvement in runtime.
