Adds two SparseTensor objects to produce another SparseTensor.

The input SparseTensor objects' indices are assumed ordered in standard lexicographic order. If this is not the case, before this step run SparseReorder to restore index ordering.

By default, if two values sum to zero at some index, the output SparseTensor would still include that particular location in its index, storing a zero in the corresponding value slot. To override this, callers can specify thresh, indicating that if the sum has a magnitude strictly smaller than thresh, its corresponding value and index would then not be included. In particular, thresh == 0 (default) means everything is kept and actual thresholding happens only for a positive value.

In the following shapes, nnz is the count after taking thresh into account.

a_indices A Tensor of type int64. 2-D. The indices of the first SparseTensor, size [nnz, ndims] Matrix.
a_values A Tensor. Must be one of the following types: float32, float64, int32, uint8, int16, int8, complex64, int64,