code: public synchronized int addColumn(SparseArray<? extends Number> column) {
          if (isFinished)
              throw new IllegalStateException(
                  "Cannot add columns to a MatrixBuilder that is finished");
  
          for (int r : column.getElementIndices()) {
              // NB: Matlab sparse format is in [row col val] format
              //
              // NOTE: Matlab indices start at 1, not 0, so update all the row
              // and column values to be Matlab formatted.
              addEntry(r + 1, curColumn + 1, column.get(r).doubleValue());
          }
          return ++curColumn;
      }
docs: {@inheritDoc}