docs: private long[][] computeDimensionMap(List<DoubleIntInt> z_ijs, final int dim, final int numc) {
      // mapping cluster index -> dimensions
      long[][] dimensionMap = new long[numc][((dim - 1) >> 6) + 1];
      int max = Math.max(k * l, 2);
      for(int m = 0; m < max; m++) {
        DoubleIntInt z_ij = z_ijs.get(m);
        long[] dims_i = dimensionMap[z_ij.dimi];
        BitsUtil.setI(dims_i, z_ij.dimj);
  
        if(LOG.isDebugging()) {
          LOG.debugFiner(new StringBuilder().append("z_ij ").append(z_ij).append('\n') //
              .append("D_i ").append(BitsUtil.toString(dims_i)).toString());
        }
      }
      return dimensionMap;
    }