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Two Apollo Guidance Computers accompanied each lunar mission. One CPU was housed in the lower equipment bay of the command module, with one DSKY display-keyboard unit adjacent to the CPU, and a second DSKY at the navigator's station of the main display console.
The other AGC was in the lunar module. Obviously its DSKY was in the ascent stage with the astronauts. But where was its CPU: in the ascent stage, or in the descent stage?
There is a figure showing the location of the Lunar Guidance Computer LGC within the LM. See page GN-11 in the PDF. Similar figures here (1) (figure 3.2-3 on page 40 or 3-7), (2) (figure 2.1-1 on first page 2.1-1).
The LGC needs connections to the DSKY, the Coupling Data Unit, the Navigation Base and many more other units. Therefore its best place is within the pressurized cabin of the LM in the ascent stage. It is used for ascent and descent, mounting it to the descent stage is not possible.
Placing the LGC outside the pressurized cabin would require several additional gas tight connectors mounted to the cabin walls. To keep it as simple and reliable as possible, these additional connectors should be avoided.
The Landing Radar Antenna (lower right of image) is used for descent only, its best place is at the descent stage near a landing leg.
From this page: "The LGC (with related equipment) was mounted behind the astronauts at the back of the LM cabin. In front of the astronauts was a rigid structure called the "Nav Base" that held an alignment telescope and the Inertial Measurement Unit (IMU) in a fixed geometrical relationship. The computer's Display and Keyboard Unit (DSKY) was mounted like a desk between the two astronauts."
There is indirect evidence that it is in the ascent stage.
According to https://history.nasa.gov/afj/compessay.html, there are several lunar guidance computer programs related to ascent:
P12 Powered Ascent Guidance
P42 APS Thrusting
P71 APS Abort
These would only make sense if the computer were in the ascent stage, as the descent stage is left behind.
Nonetheless, I find it odd that NASA gives very specific documentation about the location of the AGC in the CM, but does not for the LM.
The CM housed the computer in a lower equipment bay, near the navigator's station. Block II measured 24 by 12.5 by 6 inches, weighed 70.1 pounds, and required 70 watts at 28 volts DC. The machine in the lunar module was identical.