HI!
Yesterday I wrote on the MResetZ() which allows us to get the status of a Qubit and release it. Well, at the end of each Q# operation, all the used Qubits need to be released for the simulator to work properly.
The following sample code will show a bad sample where a Qubit is used and not released correctly:
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| operation HGateWithOutReset (initial: Result) : (Result) | |
| { | |
| body | |
| { | |
| mutable res = Zero; | |
| using (qubits = Qubit[2]) | |
| { | |
| let qubit1 = qubits[0]; | |
| let qubit2 = qubits[1]; | |
| H(qubit1); | |
| set res = M(qubit1); | |
| } | |
| return (res); | |
| } | |
| } |
So, in runtime we will find this amazing and cool error:
Microsoft.Quantum.Simulation.Simulators.Exceptions.ReleasedQubitsAreNotInZeroState
HResult=0x80131500
Message=Released qubits are not in zero state.
Source=Microsoft.Quantum.Simulation.Simulators
Microsoft Quantum Development Kit offers us a series of operations that help us to release Qubits: Reset() and ResetAll(). As its name indicates Reset() is intended to release a single Qubit and ResetAll() to release an array of Qubits.
Given a single Qubit, Reset() evaluates the Qubit state and ensures that the Qubit is in the state |0⟩ so it can be safely released.
The following 2 operations show examples of how to use these operations
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| operation HGateWithResetEachQubit (initial: Result) : (Result) | |
| { | |
| body | |
| { | |
| mutable res = Zero; | |
| using (qubits = Qubit[2]) | |
| { | |
| let qubit1 = qubits[0]; | |
| let qubit2 = qubits[1]; | |
| H(qubit1); | |
| set res = M(qubit1); | |
| Reset(qubit1); | |
| Reset(qubit2); | |
| } | |
| return (res); | |
| } | |
| } | |
| operation HGateWithResetAllQubits (initial: Result) : (Result) | |
| { | |
| body | |
| { | |
| mutable res = Zero; | |
| using (qubits = Qubit[2]) | |
| { | |
| let qubit1 = qubits[0]; | |
| let qubit2 = qubits[1]; | |
| H(qubit1); | |
| set res = M(qubit1); | |
| ResetAll(qubits); | |
| } | |
| return (res); | |
| } | |
| } |
Happy QCoding!
Greetings @ Toronto
El Bruno
References
- Microsoft Quantum Development Kit
- Q# Reference, M operation
- Q# Reference, H operation
- Q# Reference, MResetZ operation
- Q# Reference, Reset operation
- Q# Reference, ResetAll operation
My Posts
- El Bruno, Using MResetZ() to reset Qubits in Q#
- El Bruno, Qubit operations in Q#
- El Bruno, Information about Simulators on Microsoft Quantum Development Kit (Do you have 16 TB RAM?)
- El Bruno, Hello QWorld using Microsoft #Quantum Development Kit (fix to build the project) [Updated]
- El Bruno, More information about the Microsoft bet in Quantum Computing
- El Bruno, Quantum Computing, let’s add this one to Artificial Intelligence and Mixed Reality!
El Bruno 
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