  We present a fast method for reconstructing Differential Emission Measures
(DEMs) using solar coronal data. On average, the method computes over 1000 DEMs
per second for a sample active region observed by the Atmospheric Imaging
Assembly (AIA) on the Solar Dynamics Observatory (SDO), and achieves reduced
chi-squared of order unity with no negative emission in all but a few test
cases. The high performance of this method is especially relevant in the
context of AIA, which images of order one million solar pixels per second. This
paper describes the method, analyzes its fidelity, compares its performance and
results with other DEM methods, and applies it to an active region and loop
observed by AIA and by the Extreme-ultraviolet Imaging Spectrometer (EIS) on
Hinode.
