docs: public static double elementMaxAbs( DMatrix4x4 a ) {
          double max = Math.abs(a.a11);
          double tmp = Math.abs(a.a12); if( tmp > max ) max = tmp;
          tmp = Math.abs(a.a13); if( tmp > max ) max = tmp;
          tmp = Math.abs(a.a14); if( tmp > max ) max = tmp;
          tmp = Math.abs(a.a21); if( tmp > max ) max = tmp;
          tmp = Math.abs(a.a22); if( tmp > max ) max = tmp;
          tmp = Math.abs(a.a23); if( tmp > max ) max = tmp;
          tmp = Math.abs(a.a24); if( tmp > max ) max = tmp;
          tmp = Math.abs(a.a31); if( tmp > max ) max = tmp;
          tmp = Math.abs(a.a32); if( tmp > max ) max = tmp;
          tmp = Math.abs(a.a33); if( tmp > max ) max = tmp;
          tmp = Math.abs(a.a34); if( tmp > max ) max = tmp;
          tmp = Math.abs(a.a41); if( tmp > max ) max = tmp;
          tmp = Math.abs(a.a42); if( tmp > max ) max = tmp;
          tmp = Math.abs(a.a43); if( tmp > max ) max = tmp;
          tmp = Math.abs(a.a44); if( tmp > max ) max = tmp;
  
          return max;
      }