The SAGE-Spec Spitzer Legacy program: The life-cycle of dust and gas in
  the Large Magellanic Cloud. Point source classification III
  The Infrared Spectrograph (IRS) on the {\em Spitzer Space Telescope} observed
nearly 800 point sources in the Large Magellanic Cloud (LMC), taking over 1,000
spectra. 197 of these targets were observed as part of the Sage-Spec Spitzer
Legacy program; the remainder are from a variety of different calibration,
guaranteed time and open time projects. We classify these point sources into
types according to their infrared spectral features, continuum and spectral
energy distribution shape, bolometric luminosity, cluster membership, and
variability information, using a decision-tree classification method. We then
refine the classification using supplementary information from the
astrophysical literature. We find that our IRS sample is comprised
substantially of YSO and H\,{\sc ii} regions, post-Main Sequence low-mass
stars: (post-)AGB stars and planetary nebulae and massive stars including
several rare evolutionary types. Two supernova remnants, a nova and several
background galaxies were also observed. We use these classifications to improve
our understanding of the stellar populations in the Large Magellanic Cloud,
study the composition and characteristics of dust species in a variety of LMC
objects, and to verify the photometric classification methods used by mid-IR
surveys. We discover that some widely-used catalogues of objects contain
considerable contamination and others are missing sources in our sample.
