snowkylin / npn

A boolean matcher that computes the NPN canonical representative for a given boolean function.

NPN: Compute canonical representatives for boolean functions

This package is a boolean matcher. It simply computes the canonical representative, which is unique for each NPN equivalence class, for a given boolean function represented by truth table.

The backend of this package is implemented by C++ for efficiency.

Currently, this package supports boolean functions with number of inputs <= 8.

Install

pip install npn

Usage

import npn

# the truth table of f(x_2, x_1, x_0) as [f(0, 0, 0), f(0, 0, 1), f(0, 1, 0), f(0, 1, 1), ...]
tt = [True, True, True, False, True, True, True, True]
c = npn.npn_canonical_representative(tt)    # [True, True, True, True, True, True, True, False]
c_int = npn.tt_to_int(c)                    # 254 (11111110)
c, phase, perm, output_inv = npn.npn_canonical_representative(tt, return_details=True, refinement=True)

• Set return_details parameter to True to return the NPN transformation information (phase, perm, output_inv). For example, here phase = [False, False, True], perm = [0, 1, 2] and output_inv = False means (x_0, x_1, x_2) should be mapped to (x_0, x_1, x_2), then the third variable (x_2) should be inverted and the final result should not be inverted.
• Set refinement parameter to True to accelerate computation while breaking the lexicographical order of truth tables. See "Building a Better Boolean Matcher and Symmetry Detector" for details.

Build

Compile the shared library libnpn.dll and libnpn.so via CMake on Windows and Linux environment, place them in the \npn folder, then

python setup.py sdist

To upload to PyPI, run

twine upload .\dist\npn-X.X.tar.gz

Test

pip install pytest  # if you haven't install it
python -m pytest

References

1. Chai, D., and A. Kuehlmann. “Building a Better Boolean Matcher and Symmetry Detector.” In Proceedings of the Design Automation & Test in Europe Conference, 1:1–6, 2006. https://doi.org/10.1109/DATE.2006.243959.
2. Debnath, D., and T. Sasao. “Efficient Computation of Canonical Form for Boolean Matching in Large Libraries.” In ASP-DAC 2004: Asia and South Pacific Design Automation Conference 2004 (IEEE Cat. No.04EX753), 591–96, 2004. https://doi.org/10.1109/ASPDAC.2004.1337660.
3. Hinsberger, U., and R. Kolla. “Boolean Matching for Large Libraries.” In Proceedings 1998 Design and Automation Conference. 35th DAC. (Cat. No.98CH36175), 206–11, 1998. https://doi.org/10.1145/277044.277100.