invert3x3 function

List<List<double>> invert3x3(List<List<double>> m)

Inverts a 3x3 matrix.

Implementation

List<List<double>> invert3x3(List<List<double>> m) {
  final a = m[0][0], b = m[0][1], c = m[0][2];
  final d = m[1][0], e = m[1][1], f = m[1][2];
  final g = m[2][0], h = m[2][1], i = m[2][2];

  final det = a * (e * i - f * h) - b * (d * i - f * g) + c * (d * h - e * g);
  if (det.abs() < 1e-20) {
    throw ArgumentError('Matrix is singular, cannot invert');
  }
  final invDet = 1.0 / det;

  return [
    [
      (e * i - f * h) * invDet,
      (c * h - b * i) * invDet,
      (b * f - c * e) * invDet,
    ],
    [
      (f * g - d * i) * invDet,
      (a * i - c * g) * invDet,
      (c * d - a * f) * invDet,
    ],
    [
      (d * h - e * g) * invDet,
      (b * g - a * h) * invDet,
      (a * e - b * d) * invDet,
    ],
  ];
}