DumpRegister function


This documentation refers to the Classic QDK, which has been replaced by the Modern QDK.

Please see https://aka.ms/qdk.api for the API documentation for the Modern QDK.

Namespace: Microsoft.Quantum.Diagnostics

Package: Microsoft.Quantum.QSharp.Foundation

Dumps the current target machine's status associated with the given qubits.

function DumpRegister<'T> (location : 'T, qubits : Qubit[]) : Unit


location : 'T

Provides information on where to generate the state's dump.

qubits : Qubit[]

The list of qubits to report.

Output : Unit

Type Parameters



When run on the full-state simulator, the following snippet dumps the Bell state $(\ket{00} + \ket{11}) / \sqrt{2}$ to the console:

use left = Qubit();
use right = Qubit();
within {
    CNOT(left, right);
} apply {
    // The () input here denotes that the state dumped by the
    // full-state simulator should be reported to the console.
    DumpRegister((), [left, right]);


This method allows you to dump the information associated with the state of the given qubits into a file or some other location. The actual information generated and the semantics of location are specific to each target machine. However, providing an empty tuple as a location (()) typically means to generate the output to the console.

For the local full state simulator distributed as part of the Quantum Development Kit, this method expects a string with the path to a file in which it will write the state of the given qubits (i.e. the wave function of the corresponding subsystem) as a one-dimensional array of complex numbers, in which each element represents the amplitudes of the probability of measuring the corresponding state. If the given qubits are entangled with some other qubit and their state can't be separated, it just reports that the qubits are entangled.