From 6e01004535588b7ce77a5834dcdc4795884d393a Mon Sep 17 00:00:00 2001
From: Abhishek Jaisingh <abhi2254015@gmail.com>
Date: Tue, 13 Oct 2020 01:11:05 +0530
Subject: [PATCH] Add First Quantum Qiskit Code Tutorial (#3173)

* Add First Quantum Qiskit Code Tutorial

* Add Qiskit Requirement

* Address Review Comments

* fixup! Format Python code with psf/black push

* Update q1.py

* updating DIRECTORY.md

* Update and rename q1.py to single_qubit_measure.py

* updating DIRECTORY.md

Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
Co-authored-by: Christian Clauss <cclauss@me.com>
---
 DIRECTORY.md                    |  3 +++
 quantum/single_qubit_measure.py | 34 +++++++++++++++++++++++++++++++++
 requirements.txt                |  1 +
 3 files changed, 38 insertions(+)
 create mode 100755 quantum/single_qubit_measure.py

diff --git a/DIRECTORY.md b/DIRECTORY.md
index c1358b8d7..eee4ae55c 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -681,6 +681,9 @@
     * [Sol1](https://github.com/TheAlgorithms/Python/blob/master/project_euler/problem_99/sol1.py)
   * [Validate Solutions](https://github.com/TheAlgorithms/Python/blob/master/project_euler/validate_solutions.py)
 
+## Quantum
+  * [Single Qubit Measure](https://github.com/TheAlgorithms/Python/blob/master/quantum/single_qubit_measure.py)
+
 ## Scheduling
   * [First Come First Served](https://github.com/TheAlgorithms/Python/blob/master/scheduling/first_come_first_served.py)
   * [Round Robin](https://github.com/TheAlgorithms/Python/blob/master/scheduling/round_robin.py)
diff --git a/quantum/single_qubit_measure.py b/quantum/single_qubit_measure.py
new file mode 100755
index 000000000..99d807b03
--- /dev/null
+++ b/quantum/single_qubit_measure.py
@@ -0,0 +1,34 @@
+#!/usr/bin/env python3
+"""
+Build a simple bare-minimum quantum circuit that starts with a single 
+qubit (by default, in state 0), runs the experiment 1000 times, and 
+finally prints the total count of the states finally observed.
+Qiskit Docs: https://qiskit.org/documentation/getting_started.html
+"""
+
+import qiskit as q
+
+
+def single_qubit_measure(qubits: int, classical_bits: int) -> q.result.counts.Counts:
+    """
+    >>> single_qubit_measure(1, 1)
+    {'0': 1000}
+    """
+    # Use Aer's qasm_simulator
+    simulator = q.Aer.get_backend("qasm_simulator")
+
+    # Create a Quantum Circuit acting on the q register
+    circuit = q.QuantumCircuit(qubits, classical_bits)
+
+    # Map the quantum measurement to the classical bits
+    circuit.measure([0], [0])
+
+    # Execute the circuit on the qasm simulator
+    job = q.execute(circuit, simulator, shots=1000)
+
+    # Return the histogram data of the results of the experiment.
+    return job.result().get_counts(circuit)
+
+
+if __name__ == "__main__":
+    print(f"Total count for various states are: {single_qubit_measure(1, 1)}")
diff --git a/requirements.txt b/requirements.txt
index 31dc586c2..67d9bbbd8 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -7,6 +7,7 @@ numpy
 opencv-python
 pandas
 pillow
+qiskit
 requests
 scikit-fuzzy
 sklearn