Choosing an Error Target for a 2048-Qubit OQFT, Each Tenfold Tightening Costs 24 to 32 Layers

Fri, 13 Nov 2026 00:00:00 +0000

OQFT asks for one number besides the register size: the error target, --eps. It’s the average squared error you’re willing to accept over all inputs. Pick it too loose and Shor’s algorithm misses more often. Pick it too tight and you pay in depth. This case study puts numbers on that trade for a 2,048-qubit register, the size a 2048-bit RSA key calls for.

We ran oqft stats -n 2048 at four targets, from 0.1 down to 0.0001, and recorded the block width OQFT chose for each.

Error Targets on oqft.com

Choosing an Error Target for a 2048-Qubit OQFT, Each Tenfold Tightening Costs 24 to 32 Layers