docs: private void setCurrentAndMeta(final ByteMap<ExpressionDataPoint[]> 
        ordered_union) {
      for (final String id : queries.keySet()) {
        current_values.put(id, new ExpressionDataPoint[ordered_union.size()]);
        // TODO - blech. Fill with a sentinel value to reflect "no data here!"
        final int[] m = new int[ordered_union.size()];
        for (int i = 0; i < m.length; i++) {
          m[i] = -1;
        }
        single_series_matrix.put(id, m);
      }
      
      int i = 0;
      for (final Entry<byte[], ExpressionDataPoint[]> entry : ordered_union.entrySet()) {
        final ExpressionDataPoint[] idps = entry.getValue();
        for (int x = 0; x < idps.length; x++) {
          final ExpressionDataPoint[] current_dps = 
              current_values.get(index_to_names[x]);
          current_dps[i] = idps[x];
          final int[] m = single_series_matrix.get(index_to_names[x]);
          if (idps[x] != null) {
            m[i] = idps[x].getIndex();
          }
        }
        ++i;
      }
      
      // set fills on nulls
      for (final ExpressionDataPoint[] idps : current_values.values()) {
        for (i = 0; i < idps.length; i++) {
          if (idps[i] == null) {
            idps[i] = fill_dp;
          }
        }
      }
      series_size = ordered_union.size();
    }