docs: public static boolean cholU( DMatrix4x4 A ) {
  
          A.a11 = Math.sqrt(A.a11);
          A.a21 = 0;
          A.a31 = 0;
          A.a41 = 0;
          A.a12 = (A.a12)/A.a11;
          A.a22 = Math.sqrt(A.a22-A.a12*A.a12);
          A.a32 = 0;
          A.a42 = 0;
          A.a13 = (A.a13)/A.a11;
          A.a23 = (A.a23-A.a12*A.a13)/A.a22;
          A.a33 = Math.sqrt(A.a33-A.a13*A.a13-A.a23*A.a23);
          A.a43 = 0;
          A.a14 = (A.a14)/A.a11;
          A.a24 = (A.a24-A.a12*A.a14)/A.a22;
          A.a34 = (A.a34-A.a13*A.a14-A.a23*A.a24)/A.a33;
          A.a44 = Math.sqrt(A.a44-A.a14*A.a14-A.a24*A.a24-A.a34*A.a34);
          return !UtilEjml.isUncountable(A.a44);
      }