double dotColumn(int j, Vector4 v)

Returns the dot product of column j and v.

Source 

double dotColumn(int j, Vector4 v) {
  final vStorage = v._v4storage;
  return _m4storage[j * 4] * vStorage[0] +
      _m4storage[j * 4 + 1] * vStorage[1] +
      _m4storage[j * 4 + 2] * vStorage[2] +
      _m4storage[j * 4 + 3] * vStorage[3];
}