passagemath-kissat

10.8.4 verified Sat May 09 auth: no python

Interface to the SAT solver Kissat, part of the passagemath ecosystem. Provides a Python wrapper for the Kissat SAT solver, which is a compact, clean, and efficient SAT solver. Current version 10.8.4, compatible with Python 3.11–3.14. Release cadence is irregular, following upstream Kissat releases.

pip install passagemath-kissat

Common errors

error ModuleNotFoundError: No module named 'passagemath' ↓

cause The passagemath package is not installed. passagemath-kissat is a namespace package; you need to install the base passagemath package or at least ensure the namespace is available.

fix

pip install passagemath-kissat (will also install passagemath-base if not present).

error ImportError: cannot import name 'KissatSolver' from 'passagemath.kissat' ↓

cause The module path might be incorrect or the package version is too old (before 10.8.0).

fix

Ensure you have passagemath-kissat >= 10.8.0 installed. Use 'from passagemath.kissat import KissatSolver' exactly.

error TypeError: add_clause() takes 2 positional arguments but 3 were given ↓

cause The function expects a single list/tuple of literals, not separate arguments.

fix

Pass a single list: solver.add_clause([1, 2]) instead of solver.add_clause(1, 2).

Warnings

gotcha Variable indices must be positive integers. Zero and negative non-zero values are not allowed for variable numbers in add_clause(). Only negative literals (e.g., -1) are used to denote negation. ↓

fix Use positive integers for variables, and negate by prefixing with '-' (e.g., -1).

breaking The API changed significantly from the standalone 'kissat' package. The standalone version used 'kissat.solve()' with different return types. In passagemath-kissat, the solver is a class with a different interface. ↓

fix Use the new import: 'from passagemath.kissat import KissatSolver' and instantiate before solving.

deprecated The function 'solve_sat' that returns a dictionary is deprecated in favor of the KissatSolver class which returns an object with attributes. ↓

fix Switch to KissatSolver.solve() which returns a result object with .satisfiable and .model.

Imports

KissatSolver
wrong
```
import kissat
```
correct
```
from passagemath.kissat import KissatSolver
```
Direct import of 'kissat' is incorrect; the module is nested under passagemath.

solve_sat

wrong

from kissat import solve_sat

correct

from passagemath.kissat import solve_sat

Import path must include passagemath.

Quickstart

Basic usage: create a KissatSolver instance, add clauses (variables as positive integers), call solve(), and access satisfiability and model.

from passagemath.kissat import KissatSolver

solver = KissatSolver()
# Example: solve a simple SAT problem (a ∨ b) ∧ (¬a ∨ c)
solver.add_clause([1, 2])   # a (var 1) or b (var 2)
solver.add_clause([-1, 3])  # not a or c (var 3)
result = solver.solve()
print('SAT' if result.satisfiable else 'UNSAT')
if result.satisfiable:
    print('Model:', result.model)
    # Model is a list of variable assignments (e.g., [-2, 1, 3] meaning b=False, a=True, c=True)