docs: public static boolean isEquals(ZMatrixD1 a , ZMatrixD1 b , double tol )
      {
          if( a.numRows != b.numRows || a.numCols != b.numCols ) {
              return false;
          }
  
          if( tol == 0.0 )
              return isEquals(a,b);
  
          final int length = a.getDataLength();
  
          for( int i = 0; i < length; i++ ) {
              if( !(tol >= Math.abs(a.data[i] - b.data[i])) ) {
                  return false;
              }
          }
          return true;
      }