getP method Null safety

bool getP(
  1. int r,
  2. int c
)

Get the permutation matrix P value at the given row, column. Since it's a permuted identity matrix, the value is 0 or 1, so we give it as a bool. A P matrix only exists for an LU-decomposed matrix.

Implementation

bool getP(int r, int c) {
  assert(isLU);
  checkIndices(r, c);
  final swaps = _rowSwaps!;
  return swaps[r] == c;
}