sub method

void sub (Matrix2 o)

Subtract o from this.

Implementation 

void sub(Matrix2 o) {
  final Float64List oStorage = o._m2storage;
  _m2storage[0] = _m2storage[0] - oStorage[0];
  _m2storage[1] = _m2storage[1] - oStorage[1];
  _m2storage[2] = _m2storage[2] - oStorage[2];
  _m2storage[3] = _m2storage[3] - oStorage[3];
}