code: public void setSparseComponent(int component, int index, double value) {
      if (component >= pointers.length) {
        increaseSizeTo(component + 1);
      }
      double[] sparseInfo = new double[2];
      sparseInfo[0] = index;
      sparseInfo[1] = value;
      pointers[component] = sparseInfo;
      sparse[component] = true;
      copyOnWrite[component] = false;
    }
docs: Sets a single component of the concat vector value as a sparse, one hot value.
  
  @param component the index of the component to set
  @param index     the index of the vector to one-hot
  @param value     the value of that index