code: function(sbmA, sbmB) {
      // check size
      if (sbmA.x !== sbmB.x || sbmA.y !== sbmB.y) {
        return false
      }
  
      // check
      return _.every(sbmA.data, function (line, idx) {
        return _.isEqual(line.sort(), sbmB.data[idx].sort())
      })
    }
docs: are both matrices equal ?