docs: public static void elementMult( DMatrix5 a , DMatrix5 b , DMatrix5 c ) {
          c.a1 = a.a1*b.a1;
          c.a2 = a.a2*b.a2;
          c.a3 = a.a3*b.a3;
          c.a4 = a.a4*b.a4;
          c.a5 = a.a5*b.a5;
      }