public boolean epsilonEquals(Matrix3d m1, double epsilon) {
	  return  Math.abs(m00 - m1.m00) <= epsilon
		&& Math.abs(m01 - m1.m01) <= epsilon
		&& Math.abs(m02 - m1.m02 ) <= epsilon

		&& Math.abs(m10 - m1.m10) <= epsilon
		&& Math.abs(m11 - m1.m11) <= epsilon
		&& Math.abs(m12 - m1.m12) <= epsilon

		&& Math.abs(m20 - m1.m20) <= epsilon
		&& Math.abs(m21 - m1.m21) <= epsilon
		&& Math.abs(m22 - m1.m22) <= epsilon;
      }