docs: public void addTranslation(double[] v) {
      assert (v.length == dim);
  
      // reset inverse transformation - needs recomputation.
      inv = null;
  
      double[][] homTrans = unitMatrix(dim + 1);
      for(int i = 0; i < dim; i++) {
        homTrans[i][dim] = v[i];
      }
      trans = times(homTrans, trans);
    }