code: public SparseTensor elementwiseExpSparse() {
      double[] newValues = new double[values.length];
      for (int i = 0; i < values.length; i++) {
        newValues[i] = Math.exp(values[i]);
      }
      return new SparseTensor(getDimensionNumbers(), getDimensionSizes(), keyNums, newValues);
    }
docs: Sparsely computes e to the power of each element in this tensor.
  For keys which are present in this {@code SparseTensor}, this
  operation is identical to {@link #elementwiseExp()}. Keys which
  are not present in this tensor are also not present in the result
  (and therefore have value 0).
  
  @return