docs: public static boolean isLowerTriangle(ZMatrixRMaj A , int hessenberg , double tol ) {
          tol *= tol;
          for( int i = 0; i < A.numRows-hessenberg-1; i++ ) {
              for( int j = i+hessenberg+1; j < A.numCols; j++ ) {
                  int index = (i*A.numCols+j)*2;
  
                  double real = A.data[index];
                  double imag = A.data[index+1];
                  double mag = real*real + imag*imag;
  
                  if( !(mag <= tol) ) {
                      return false;
                  }
              }
          }
          return true;
      }