code: function(sbmA, sbmB) {
      // if not the same sizes
      if (sbmA.x != sbmB.x || sbmA.y != sbmB.y) {
        return
      }
      // create the matrix
      var mat = {}
      mat.x = sbmA.x
      mat.y = sbmA.y
      mat.data = []
      // populate
      for (var i = 0; i < mat.x; i++) {
        mat.data[i] = _.union(sbmA.data[i], sbmB.data[i]).sort()
      }
      // return matrix
      return mat
    }
docs: OR the two matrices