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Select operation

  • Article

Fully qualified name: Microsoft.Quantum.Unstable.TableLookup.Select

operation Select(data : Bool[][], address : Qubit[], target : Qubit[]) : Unit is Adj + Ctl

Summary

Performs table lookup using a SELECT network

Description

Assuming a zero-initialized target register, this operation will initialize it with the bitstrings in data at indices according to the computational values of the address register.

Input

data

The classical table lookup data which is prepared in target with respect to the state in address. The length of data must be less than 2ⁿ, where 𝑛 is the length of address. Each entry in data must have the same length that must be equal to the length of target.

address

Address register

target

Zero-initialized target register

Remarks

The implementation of the SELECT network is based on unary encoding as presented in [1]. The recursive implementation of that algorithm is presented in [3]. The adjoint variant is optimized using a measurement-based unlookup operation [3]. The controlled adjoint variant is not optimized using this technique.

References

  1. arXiv:1805.03662 "Encoding Electronic Spectra in Quantum Circuits with Linear T Complexity"
  2. arXiv:1905.07682 "Windowed arithmetic"
  3. arXiv:2211.01133 "Space-time optimized table lookup"