code: public DoubleVector transform(DoubleVector column) {
          if (transform == null)
              throw new IllegalStateException(
                  "the initial matrix has not been transformed yet");
          // Create a new instance of that vector's type, which will contain the
          // updated values
          DoubleVector transformed = Vectors.instanceOf(column);
          int length = column.length();
          for (int row = 0; row < length; ++row) {
              double newValue = transform.transform(row, column);
              transformed.set(row, newValue);
          }
          return transformed;
      }
docs: {@inheritDoc}