code: public double[] get(double[] target) {
          if ((target == null) || (target.length != 6)) {
              target = new double[6];
          }
          target[0] = m00;
          target[1] = m01;
          target[2] = m02;
  
          target[3] = m10;
          target[4] = m11;
          target[5] = m12;
  
          return target;
      }
docs: Copies the matrix contents into a 6 entry double array.
  If target is null (or not the correct size), a new array will be created.