Function expectFullLinearFamily

test/compute-engine/diophantine.test.ts:212–233

* Full oracle-based check for a solvable linear Diophantine equation: (b) * every substituted parameter tuple satisfies the equation, and (c) every * brute-force point in a box is reachable by SOME parameter assignment.

(
  a: bigint[],
  c: bigint,
  bruteBound: bigint = BRUTE_BOUND
)

 * brute-force point in a box is reachable by SOME parameter assignment.
 */
function expectFullLinearFamily(
  a: bigint[],
  c: bigint,
  bruteBound: bigint = BRUTE_BOUND
): LinearSolution {
  const sol = solveLinearDiophantine(a, c);
  expect(sol).not.toBeNull();
  const s = sol as LinearSolution;

  for (const t of cartesianRange(s.nParams, -PARAM_CHECK_RANGE, PARAM_CHECK_RANGE)) {
    expect(linearSatisfies(a, c, substitute(s, t))).toBe(true);
  }

  const bf = bruteForceLinear(a, c, bruteBound);
  expect(bf.length).toBeGreaterThan(0);
  for (const x of bf) {
    const t = invertParams(s, x);
    expect(t).not.toBeNull();
    expect(linearSatisfies(a, c, substitute(s, t as bigint[]))).toBe(true);
  }
  return s;
}

function expectNoLinearSolution(a: bigint[], c: bigint) {
  expect(solveLinearDiophantine(a, c)).toBeNull();