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| ## Features Matrix for Distinct Count Sketches |
| |
| Category | Sub-Category | Theta | Tuple | HLL | CPC | |
| :-------:|:------------:|:-----:|:-----:|:---:|:---:| |
| Space Accuracy Config | Min Log Precision (Min LgK) | 4 | 4 | 4 | 4 | |
| | Max Log Precision (Max LgK) | 26 | 26 | 21 | 26 | |
| | Min Log Sparse Precision | 64 | 64 | 26 | 26 | |
| | Max Log Sparce Precision | 64 | 64 | 26 | 26 | |
| Space Accuracy Factors | Entropy bits / slot = b | 64 | 64 | 4 | 4.8 | |
| | Error Coefficient = C | 1 | 1 | 1.04 | 0.69 | |
| | HIP Error Coefficient = C | | | 0.83 | 0.59 | |
| Space Accuracy Merit<sup>1</sup> | Merging | 64 | | 4.33 | 2.31 | |
| | Not Merging (HIP) | | | 2.78 | 1.66 | |
| Input Types | int | Y | Y | Y | Y | |
| | long | Y | Y | Y | Y | |
| | double | Y | Y | Y | Y | |
| | String | Y | Y | Y | Y | |
| | byte[] | Y | Y | Y | Y | |
| | char[] | Y | | Y | Y | |
| | int[] | Y | Y | Y | Y | |
| | long[] | Y | Y | Y | Y | |
| Sketch results | Estimate () | double | double | double | double | |
| | Upper Bound ( Std Dev ) | double | double | double | double | |
| | Lower Bound ( Std Dev ) | double | double | double | double | |
| | Estimate (numSubSetRows) | | double | | | |
| | Upper Bound (Std Dev, numSubset Rows) | | double | | | |
| | Lower Bound (Std Dev, numSubset Rows) | | double | | | |
| | Iterator() | Y | Y | Y | Y | |
| Set Operations | Union | Y | Y | Y | Y | |
| | Intersection | Y | Y | | | |
| | Difference | Y | Y | | | |
| | Enables full set expressions | Y | Y | | | |
| | Set Op Result Type | Sketch | Sketch | Sketch | Sketch | |
| | Merge different LgK | Y | Y | Y | Y | |
| Serialize Operations | To Byte Array | Y | Y | Y | Y | |
| Deserialize Operations | Heapify() | Y | Y | Y | Y | |
| | Wrap() | Y | Y | Y | | |
| | WritableWrap | Y | Y | Y | | |
| Languages | Java | Y | Y | Y | Y | |
| | C++ | Y | | Y | Y | |
| | Python<sup>2</sup> | Y | | Y | Y | |
| | Binary compatibility across Languages | Y | Y | Y | Y | |
| Other Operations and Modes | Jaccard Index | Y | | | | |
| | Off-Heap Operation | Y | Y | Y | Y | |
| | Associative Columns | | Y | | | |
| | Generic Extensions | | Y | | | |
| | User Specified Hash Seed | Y | | | Y | |
| | Pre Sampling | Y | Y | | | |
| |
| ____ |
| <sup>1</sup> Space Accuracy Merit (Lower is better) = b * C^2 = b * K * RSE^2<br> |
| <sup>2</sup> See [Python Install Instructions](https://github.com/apache/datasketches-python)<br> |
| |
| |
