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Questions tagged [programming]

For questions relating to the process of assembling quantum programs that can be executed on a quantum computer.

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1answer
29 views

Import from qiskit-aqua error

I try to use Quantum SVM kernel algorithm: multiclass classifier extension. This is my code section with imports ...
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2answers
70 views

Problems with qiskit-terra: missing members of instance QuantumCircuit

I have installed a Python 3.7.2, download anaconda and visual studio code. Install Qiskit SDK 0.5.3. But when I launch my first test program from https://github.com/Qiskit/qiskit-terra I received a ...
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1answer
31 views

Qiskit predecessor and successor map of DAG circuits

I am trying to figure out how to use the functions "_make_pred_succ_maps". Here is a description of the function from Github: ...
3
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2answers
103 views

Finding the second smallest number. Is it achievable in QC?

I have a set of numbers in a superposition state (example: 3,8,1,5) in a quantum register (of 3 qubits). So I try to find the $n^{\text{th}}$ smallest number (...
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0answers
33 views

What are reasonable noise/dephasing parameters for QuEST to emulate state-of-the-art quantum computers?

The QuEST code allows for simulation of quantum computers taking dephasing and depolarizing noise into account via one and two qubit dephasing and depolarization. What are realistic parameters for ...
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1answer
64 views

What language is more suitable for quantum machine learning algorithms?

What language is more suitable for quantum machine learning algorithms? Is it right that it's Python + Pyquil? Or something else? And do you know the sources where you can see the sample codes of ...
3
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1answer
67 views

For CNOT gate with control qubit set to 1, the measured state of the second qubit unexpectedly depends on the measurement

I have the following circuit in qiskit. It is a simple CNOT operation with the control qubit set to 1, by running the control qubit through an X-gate. However, when I measure the 2nd qubit, I get the ...
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4answers
147 views

Which quantum computing programming language should I learn?

Which quantum computing programming language should I learn? What are the benefits of said language? As of Wikipedia, there's quite a bit to choose from. I'm looking to develop end-user applications (...
2
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1answer
38 views

Building an N-qubit Controlled S Gate

I've been beating my head against this problem for three days now and I just can't seem to crack it. To construct an N-qubit controlled Unitary gate, I can do something like this (note I'm using ...
3
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1answer
58 views

“Wait” gate throws an error “NotImplementedError: ('No decomposition rules defined for ', 'wait')”

My Quantum circuit contains "Wait" Gate. When I try to execute it (qasm_simulator or unitary-simulator), it throws an error . ...
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1answer
45 views

Cannot load account with Qiskit

I just got started with Qiskit. When I tried to save my account with the API token from IBMQ website, I got the error: ...
3
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1answer
49 views

How to add control to gates in Cirq?

My question is very simple. I know there is a method to add a control to previously defined gates. I saw in the API of cirq that there is a command Controlled gate (here). I'm not understanding though ...
3
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1answer
46 views

Consistent QISkit error: “All devices are currently unavailable”

I am attempting to run the following on a remote backend through QISkit: ...
3
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1answer
30 views

How to set a starting state in cirq?

I'm learning how to use the cirq library. Every time I set up a circuit the starting state of the qubits is $|0000..0\rangle$. Is there any way to make the starting state different? I'm thinking of ...
4
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1answer
28 views

Using parametrised values and 'Symbols' in Cirq

I'm just wondering how one should go about using parametrised values and the Symbol object that gets resolved at runtime? For example, if I would like to implement the gate $R_x(\theta) = e^{-i\theta/...
2
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1answer
64 views

ProjectQ - In which part of the controlled gate object are the control bits scored

I've been trying to decompose the ProjectQ objects and I could manage to decompose non-controlled gates and daggered gates. But I noticed that the object of a controlled version of a gate is the ...
3
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1answer
65 views

Is it possible to create a superposition in IBMQ QISkit which has probability amplitudes $|a|\neq |b|$?

For example, we can create a single qubit state with a polar angle of $\pi/2$ with the Hadamard gate. But, can we create a state such as this, $$\Psi = \cos(\pi/8)|0\rangle + \sin(\pi/8)|1\rangle$$ ...
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2answers
75 views

Is programming in quantum computer same as programming in quantum simulator in classical computer?

I just started programming in Q# and I wonder if the coding for Q# in classical computer would be the same as coding in a quantum computer. Obviously, these 2 kinds of computers work differently, so I ...
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1answer
90 views

QISKit warrning on marshmallow

I have updated qiskit module but unfortunately, it doesn't work it says ...
4
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1answer
62 views

Qiskit - How do we measure the same single qubit system multiple times while also getting the counts/results after each measurement?

I am able to apply multiple measurements (2) to the same qubit system. However, I would like to get the counts right after each measurement is executed. I realize that the counts should be the same ...
3
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1answer
34 views

LaTeX error when drawing circuits with Qiskit

I am currently running the following document from this Qiskit documentation. This notebook is running in Jupyter, and I started Jupyter from the Mac terminal within a Conda environment. Normally, ...
5
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1answer
74 views

What resources are available for learning QCL?

I'm struggling to find much about the language QCL, rather than about quantum computing itself. Is there anything out there like that? It doesn't have to be free.
4
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2answers
62 views

Why is Grover's algorithm not converging monotonically? (Python implementation)

I have tried to implement Grover's algorithm for three qubits in python/numpy and the first two iterations work like a charm but the third one starts to diverge. Is this expected, or is there a bug in ...
4
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1answer
48 views

Grover's algorithm oracle matrix

I'm trying to implement Grover's algorithm in pyQuil, but I'm having trouble creating the oracle matrix given the function $f$, where $f(x)=1$ if $x=w$ and $f(x)=0$ otherwise. In most of the ...
4
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1answer
183 views

Creating controlled R1 gates in Q#?

I know how to create controlled versions of gates like X, Y, Z. For example, a controlled X gate would be implemented by writing (Controlled X)([control],target); ...
3
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1answer
36 views

Type error creating R gate in Q#?

The R operation in Q# is listed by Microsoft in the documentation as follows operation R (pauli : Pauli, theta : Double, qubit : Qubit) : Unit However, when I try ...
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1answer
36 views

Qiskit: 'per shot' result

Is there a way to access the results of measurements 'per shot' performed on a backend such as one of the real IBM machines? I know it can generate a histogram from the cumulative data, but I was ...
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0answers
22 views

QE error: No handlers could be found for logger

When I run a QASM program on a QE simulator, I get this error. No handlers could be found for logger "IBMQuantumExperience.IBMQuantumExperience" What ...
3
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1answer
106 views

Why can't I connect to an IBMQ device?

I was trying the qiskit Terra tutorial and it seems that the code provided to connect to an actual quantum computer doesn't run properly. With my API token generated and stored into the variable "...
4
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1answer
204 views

ImportError: cannot import name 'QuantumProgram' from 'qiskit'

I get below error when I run a code on spyder environment: File C:/MYPYTHON Programs/My Quantum Programs/Shor algo.py, line 4, in from ...
4
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1answer
99 views

Deprecation warnings in Qiskit (circuit drawing)

I am just starting to get around Qiskit, I'm going at baby steps, so I tried to run the code below and I noticed three things: I tried using ...
3
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1answer
117 views

Path to learn Qiskit as a tool for the future

I am an undergraduate in Engineering physics, yet to take classes on Quantum mechanics, but none (if I'm not mistaken) on quantum information and quantum algorithms, and I am curious about the subject ...
3
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2answers
154 views

Why won't Qiskit ccx gate accept registers?

In Qiskit, they have the concept of a Toffoli gate (ccx). However, the following code throws an error: ...
8
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1answer
135 views

Submitting jobs to IBM devices without Python

Qiskit can be used to submit jobs to IBM devices using Python (or Swift and JavaScript). But what if I want to use a different language? For example, suppose I have a specific circuit I want to run. ...
2
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1answer
97 views

Plotting data in QISKit using plot_histogram

I'm trying to plot a set of data using plot_histogram, but the rendered image looks like this (the larger values are outside the image): How can I set the y-...
1
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1answer
56 views

TypeError: unorderable types: QuantumRegister() >= int()

I've been using qiskit for about a year now, and as of late, I've had issues finding an available backend to run my circuit on. Looking into the matter, I reinstalled qiskit to find that most ...
3
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1answer
65 views

How do I get a list of control qubits from Q# operations when tracing the simulation in C#?

I want to write code that prints out the controls of each operation executed during a simulation in Q#. For example this code prints the control counts: ...
5
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1answer
126 views

Status of software packages for quantum compiling

By "quantum compiling", what I mean is classical algorithms to solve the following problem: given a $SU(D)$ matrix $U$ (the goal) and a set of $SU(D)$ unitary matrices $V_1 \cdots V_N$ (the gates), ...
3
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1answer
42 views

cirq.ControlledGate from sub-circuit generator

In Cirq, is it possible to take a sub-circuit generator and use it as the sub_gate in a cirq.ControlledGate? ...
3
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1answer
78 views

Can I remove gates from a QuantumCircuit?

Suppose I want to implement run several circuits one after another, but they are constructed in a similar fashion. I could reinstantiate a QuantumCircuit for each ...
4
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1answer
84 views

How can noise on a device be simulated using measured noise parameters?

The real devices used as backends for Qiskit have calibration data that quantifies errors ($T_1$ and $T_2$, gate fidelities, etc). This can be accessed by, for example ...
2
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1answer
53 views

Result of a job for a list of circuits on QISKit

Suppose Circuits= [circuit1, circuit2, ..., circuitn] is a list of defined circuits. Then, ...
3
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1answer
87 views

Representing a real valued vector with qubits

I have some understanding that with qubits, I can represent a $2^n$ size vector using only $n$ qubits. However, I'm having trouble putting this together in a way that can make a useful circuit. Say I ...
4
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2answers
92 views

Does Q# have a bigint type?

Shor's algorithm works with very large integers; larger than 64 bits. So the built-in 64-bit Int type is insufficient for doing the classical processing (e.g. ...
2
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1answer
47 views

How do I multiply an integer and a double in Q#?

If I write this: function f(n: Int) : Double { return 1.5*n; } I get an error: ...
3
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1answer
54 views

How do I name the adjoint of an operation in Q#?

For example, if I've defined the operation PlusEqual, I'd like to say operation MinusEqual = Adjoint PlusEqual; but this ...
2
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0answers
40 views

Introspecting quantum circuit execution on Qiskit Aer simulators

Is there any way to get information from intermediate points in the execution of a quantum circuit. This is not possible on real quantum hardware but would be very useful on the Aer simulators for ...
4
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1answer
121 views

How do I write functions that modify operations in Q#?

In Q#'s type documentation, it is mentioned that you can create signatures like this: ...
2
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1answer
51 views

Programmatic access to wavefunction in Q# for tests

I'm trying to write unit tests for some small Q# operations. It would be ideal if I could access the wavefunction. Is there a way to get it? I found ...
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2answers
78 views

How do I produce circuit diagrams from a Q# program?

If I implement an adder operation in Q#, I'd like to see a quantum circuit diagram of what that adder is doing in order to check that it looks right. Is there a built-in way to do this?