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Floating-point Binary Fractions: Do math in base 2!

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An implementation of a floating-point binary fractions class and module in Python. Work with binary fractions and binary floats with ease!

This module allows one to represent integers, floats and fractions as binary strings.

  • e.g. the integer 3 will be represented as string '0b11'.
  • e.g. the float -3.75 will be represented as string '-0b11.11'.
  • e.g. the fraction 1/2 will be represented as string '0b0.1'
  • Exponential representation is also possible: '-0b0.01111e3', '-0b11.1e1' or '-0b1110e-2' all represent float -3.75.
  • two's complement representation is possible too: '11.11' for -1.25 in decimal, or '-0b1.01' in binary fraction.

Many operations and transformations are offered. You can sum, subtract, multiply, and divide long floating-point binary fractions. You can compute power of them, shift them left, shift them right, etc.

Basic representation of binary fractions and binary floats: A binary fraction is a subset of binary floats. Basically, a binary fraction is a binary float without an exponent (e.g. '-0b101.0101'). Let's have a look at an example binary float value to see how it is represented.

 prefix '0b' to indicate "binary" or "base 2" || || decimal point || | || | exponent separator || | | || | | exponent in base 10 (not in base 2!) || | | || -0b101.0101e-34 <-- example floating-point binary fraction | ||| |||| | sign ||| |||| exponent sign ||| |||| ||| fraction bits in base 2 ||| integer bits in base 2 

If you are curious about floating point binary fractions, have a look at:

If you are curious about Two's complement:

License:

  • GPL v3 or later

Features:

  • Python 3
  • constructors for various types: int, float, Fraction, str, TwosComplement, Binary
  • supports many operators: +, -, *, /, //, %, **, <<, >>, ~, &, ...
  • supports many methods: not, abs, round, floor, ceil, ...
  • internally the value is kept as a Fraction and most operations are done in Fractions. This results in better performance and infinite precision. Only a few limited operations such as 'and', 'or', 'xor', and 'invert' are done on strings.
  • very high precision
  • many operations are lossless, i.e. with no rounding errors or loss of precision
  • supports very long binary fractions
  • supports exponential representations
  • well documented
    • Please read the documentation inside the source code (binary.py).
    • Or look at the pydoc-generated documentation in README.md.
  • well tested
    • over 1600 test cases

Sample usage, Example calls:

Please have a look at the short example program that uses the Binary class and module. See file binary_sample.py.

The sample source code looks like this:

#!/usr/bin/python3 # Sample program using the Binary class and module. # Install with: pip3 install --upgrade binary-fractions if __name__ == "__main__": from binary_fractions import TwosComplement, Binary from math import ceil, floor bf1str: str = "-1.01" # -1.25 bf2str: str = "10.1" # 2.5 bf3str: str = "10.1e-3" # 2.5/8 tcstr1: str = "10.1" # -1.5 in two's complement, '-0b1.1' as binary fraction tcstr2: str = "100001001000.1" # -1975.5 in two's complement, '-0b11110111000.1' fl1: float = 2.3 fl2: float = -1975.5 bf1: Binary = Binary(bf1str) bf2: Binary = Binary(bf2str) bf3: Binary = Binary(bf3str) tc1: TwosComplement = TwosComplement(tcstr1) tc2: TwosComplement = TwosComplement(tcstr2) tc3: TwosComplement = TwosComplement(fl2) print("Sample program demonstrating binary fractions class and module:") print(f"Binary({fl1}) = {Binary(fl1)}") print(f"Binary({fl2}) = {Binary(fl2)}") print(f"Binary({bf3str}) = {Binary(bf3str)}") print(f"{bf1} = {bf1}") print(f"{bf1} + {bf2} = {bf1+bf2}") print(f"{bf1} - {bf2} = {bf1-bf2}") print(f"{bf1} * {bf2} = {bf1*bf2}") print(f"{bf1} / {bf2} = {bf1/bf2}") print(f"{bf1} // {bf2} = {bf1//bf2}") print(f"{bf1} % {bf2} = {bf1%bf2}") print(f"{bf2} ** {bf1} = {bf2**bf1}") print(f"{bf1} >> {1} = {bf1>>1}") print(f"{bf1} << {1} = {bf1<<1}") print(f"abs({bf1}) = {abs(bf1)}") print(f"round({bf1}) = {round(bf1)}") print(f"ceil({bf1}) = {ceil(bf1)} (int)") print(f"Binary('{bf1}').ceil() = {bf1.ceil()} (Binary)") print(f"floor({bf1}) = {floor(bf1)} (int)") print(f"Binary('{bf1}').floor() = {bf1.floor()} (Binary)") print(f"int({bf1}) = {int(bf1)}") print(f"float({bf1}) = {float(bf1)}") print(f"str({bf1}) = {str(bf1)}") print(f"str({bf3}) = {str(bf3)}") print(f"Fraction({bf1}) = {bf1.fraction}") print(f"Binary({bf1}).fraction = {bf1.fraction}") print(f"Binary({fl2}).string = {Binary(fl2).string}") print(f"{bf1} & {bf2} = {bf1&bf2}") print(f"{bf1} | {bf2} = {bf1|bf2}") print(f"{bf1} ^ {bf2} = {bf1^bf2}") print(f"~(floor({bf2})) = {~(floor(bf2))}") print(f"type({bf1}) = {type(bf1)}") print(f"type({tc1}) = {type(tc1)}") print(f"Binary('{bf3}').to_no_exponent() = {bf3.to_no_exponent()}") print(f"Binary('{bf3}').to_no_mantissa() = {bf3.to_no_mantissa()}") # scientific notation print(f"Binary('{bf3}').to_sci_exponent() = {bf3.to_sci_exponent()}") # engineering notation print(f"Binary('{bf3}').to_eng_exponent() = {bf3.to_eng_exponent()}") print(f"Binary('{bf1}').to_twos_complement() = {bf1.to_twoscomplement()}") print(f"Binary(TwosComplement('{tcstr1}')) = {Binary.from_twoscomplement(tc1)}") print(f"Binary(TwosComplement('{tcstr2}')) = {Binary.from_twoscomplement(tc2)}") print(f"Binary(TwosComplement({fl2})) = {Binary.from_twoscomplement(tc3)}") print(f"TwosComplement({fl2}) = {TwosComplement(fl2)}") print("And there are more operands, more methods, more functions, ...") print("For more information read the documentation at:") print("https://raw.githubusercontent.com/Jonny-exe/binary-fractions") 

When executed with the command python3 binary_sample.py, it returns these results:

Sample program demonstrating binary fractions class and module: Binary(2.3) = 0b10.01001100110011001100110011001100110011001100110011 Binary(-1975.5) = -0b11110110111.1 Binary(10.1e-3) = 0b10.1e-3 -0b1.01 = -0b1.01 -0b1.01 + 0b10.1 = 0b1.01 -0b1.01 - 0b10.1 = -0b11.11 -0b1.01 * 0b10.1 = -0b11.001 -0b1.01 / 0b10.1 = -0b0.1 -0b1.01 // 0b10.1 = -0b1 -0b1.01 % 0b10.1 = 0b1.01 0b10.1 ** -0b1.01 = 0b0.010100010110111110001011100001001001101110110100110011 -0b1.01 >> 1 = -0b0.101 -0b1.01 << 1 = -0b10.1 abs(-0b1.01) = 0b1.01 round(-0b1.01) = -0b1 ceil(-0b1.01) = -1 (int) Binary('-0b1.01').ceil() = -0b1 (Binary) floor(-0b1.01) = -2 (int) Binary('-0b1.01').floor() = -0b10 (Binary) int(-0b1.01) = -1 float(-0b1.01) = -1.25 str(-0b1.01) = -0b1.01 str(0b10.1e-3) = 0b10.1e-3 Fraction(-0b1.01) = -5/4 -0b1.01 & 0b10.1 = 0b10.1 -0b1.01 | 0b10.1 = -0b1.01 -0b1.01 ^ 0b10.1 = -0b11.11 ~(floor(0b10.1)) = -3 type(-0b1.01) = <class 'binary.Binary'> type(10.1) = <class 'binary.TwosComplement'> Binary('0b10.1e-3').to_no_exponent() = 0b0.0101 Binary('0b10.1e-3').to_no_mantissa() = 0b101e-4 Binary('0b10.1e-3').to_sci_exponent() = 0b1.01e-2 Binary('0b10.1e-3').to_eng_exponent() = 0b101000000e-10 Binary('-0b1.01').to_twos_complement() = 10.11 Binary(TwosComplement('10.1')) = -1.1 Binary(TwosComplement('100001001000.1')) = -11110110111.1 Binary(TwosComplement(-1975.5)) = -11110110111.1 TwosComplement(-1975.5) = 100001001000.1 

Requirements:

  • Python 3
  • requires no pip packages (uses built-in math and fractions modules for math operations, uses unittest for unit testing)

Installation:

Testing, Maturity

  • run python3 binary_sample.py to execute a simple sample program
  • run python3 binary_test.py to execute all unit tests
  • Binary is relatively mature, more than 1600 test cases have been written and all passed.

Contributions:

  • PRs are welcome and very much appreciated! 👍
  • Please run and pass all existing 1600+ test cases in binary_test.py before issuing a PR.
  • File Format: linted/beautified with black
  • This project uses static typing. mypy is used for type checking.
  • Test case format: unittest
  • Documentation format: pydoc

Enjoy ❤️ !