Book Image

Dancing with Python

By : Robert S. Sutor
Book Image

Dancing with Python

By: Robert S. Sutor

Overview of this book

Dancing with Python helps you learn Python and quantum computing in a practical way. It will help you explore how to work with numbers, strings, collections, iterators, and files. The book goes beyond functions and classes and teaches you to use Python and Qiskit to create gates and circuits for classical and quantum computing. Learn how quantum extends traditional techniques using the Grover Search Algorithm and the code that implements it. Dive into some advanced and widely used applications of Python and revisit strings with more sophisticated tools, such as regular expressions and basic natural language processing (NLP). The final chapters introduce you to data analysis, visualizations, and supervised and unsupervised machine learning. By the end of the book, you will be proficient in programming the latest and most powerful quantum computers, the Pythonic way.
Table of Contents (29 chapters)
Part I: Getting to Know Python
PART II: Algorithms and Circuits
PART III: Advanced Features and Libraries
Other Books You May Enjoy
Appendix C: The Complete UniPoly Class
Appendix D: The Complete Guitar Class Hierarchy
Appendix F: Production Notes

9.3 Logic circuits

When you compose gates, you get a circuit. Figure 9.9 is the addition circuit from Chapter 1, Doing the Things That Coders Do, that adds two bits, a and b. The sum is the 2-bit number cs, with c being the carry bit. If a = b = 1, then cs is 10.

When I add 16 and 9 in base 10, I say, “add 6 to 9 to get 5, and carry a 1.” The “carry bit” is the analogy in base 2.

A simple logical addition circuit
Figure 9.9: A simple logical addition circuit

Though the circuit has two inputs and two outputs, it is not reversible. If cs is 01, then a could have been 0 and b could have been 1, or the other way around. You can see this in our Python implementation of bit_add:

def bit_add(bit_0, bit_1):
    return (bit_0 and bit_1, bit_0 ^ bit_1)

for bit_0 in (0, 1):
    for bit_1 in (0, 1):
        sum_ = bit_add(bit_0, bit_1)
        print(f"{bit_0} + {bit_1...