Add __binsparse_descriptor__ and __binsparse_dlpack__.

sparse/numba_backend/_compressed/compressed.py

@@ -844,6 +844,15 @@ def isinf(self):
     def isnan(self):
         return self.tocoo().isnan().asformat("gcxs", compressed_axes=self.compressed_axes)
 
+    # `GCXS` is a reshaped/transposed `CSR`, but it can't (usually)
+    # be expressed in the `binsparse` 0.1 language.
+    # We are missing index maps.
+    def __binsparse_descriptor__(self) -> dict:
+        return super().__binsparse_descriptor__()
+
+    def __binsparse_dlpack__(self) -> dict[str, np.ndarray]:
+        return super().__binsparse_dlpack__()
+
 
 class _Compressed2d(GCXS):
     class_compressed_axes: tuple[int]
@@ -883,6 +892,34 @@ def from_numpy(cls, x, fill_value=0, idx_dtype=None):
         coo = COO.from_numpy(x, fill_value=fill_value, idx_dtype=idx_dtype)
         return cls.from_coo(coo, cls.class_compressed_axes, idx_dtype)
 
+    def __binsparse_descriptor__(self) -> dict:
+        from sparse._version import __version__
+
+        data_dt = str(self.data.dtype)
+        if np.issubdtype(data_dt, np.complexfloating):
+            data_dt = f"complex[{self.data.dtype.itemsize // 2}]"
+        return {
+            "binsparse": {
+                "version": "0.1",
+                "format": self.format.upper(),
+                "shape": list(self.shape),
+                "number_of_stored_values": self.nnz,
+                "data_types": {
+                    "pointers_to_1": str(self.indices.dtype),
+                    "indices_1": str(self.indptr.dtype),
+                    "values": data_dt,
+                },
+            },
+            "original_source": f"`sparse`, version {__version__}",
+        }
+
+    def __binsparse_dlpack__(self) -> dict[str, np.ndarray]:
+        return {
+            "pointers_to_1": self.indices,
+            "indices_1": self.indptr,
+            "values": self.data,
+        }
+
 
 class CSR(_Compressed2d):
     """
@@ -915,6 +952,27 @@ def transpose(self, axes: None = None, copy: bool = False) -> Union["CSC", "CSR"
             return self
         return CSC((self.data, self.indices, self.indptr), self.shape[::-1])
 
+    def __binsparse_descriptor__(self) -> dict:
+        from sparse._version import __version__
+
+        data_dt = str(self.data.dtype)
+        if np.issubdtype(data_dt, np.complexfloating):
+            data_dt = f"complex[{self.data.dtype.itemsize // 2}]"
+        return {
+            "binsparse": {
+                "version": "0.1",
+                "format": "CSR",
+                "shape": list(self.shape),
+                "number_of_stored_values": self.nnz,
+                "data_types": {
+                    "pointers_to_1": str(self.indices.dtype),
+                    "indices_1": str(self.indptr.dtype),
+                    "values": data_dt,
+                },
+            },
+            "original_source": f"`sparse`, version {__version__}",
+        }
+
 
 class CSC(_Compressed2d):
     """

sparse/numba_backend/_coo/core.py

@@ -1537,6 +1537,44 @@ def isnan(self):
             prune=True,
         )
 
+    def __binsparse_descriptor__(self) -> dict:
+        from sparse._version import __version__
+
+        data_dt = str(self.data.dtype)
+        if np.issubdtype(data_dt, np.complexfloating):
+            data_dt = f"complex[{self.data.dtype.itemsize // 2}]"
+        return {
+            "binsparse": {
+                "version": "0.1",
+                "format": {
+                    "custom": {
+                        "level": {
+                            "level_desc": "sparse",
+                            "rank": self.ndim,
+                            "level": {
+                                "level_desc": "element",
+                            },
+                        }
+                    }
+                },
+                "shape": list(self.shape),
+                "number_of_stored_values": self.nnz,
+                "data_types": {
+                    "pointers_to_1": "uint8",
+                    "indices_1": str(self.coords.dtype),
+                    "values": data_dt,
+                },
+            },
+            "original_source": f"`sparse`, version {__version__}",
+        }
+
+    def __binsparse_dlpack__(self) -> dict[str, np.ndarray]:
+        return {
+            "pointers_to_1": np.array([0, self.nnz], dtype=np.uint8),
+            "indices_1": self.coords,
+            "values": self.data,
+        }
+
 
 def as_coo(x, shape=None, fill_value=None, idx_dtype=None):
     """

sparse/numba_backend/_dok.py

@@ -548,6 +548,12 @@ def reshape(self, shape, order="C"):
 
         return DOK.from_coo(self.to_coo().reshape(shape))
 
+    def __binsparse_descriptor__(self) -> dict:
+        raise RuntimeError("`DOK` doesn't support the `__binsparse_descriptor__` protocol.")
+
+    def __binsparse_dlpack__(self) -> dict[str, np.ndarray]:
+        raise RuntimeError("`DOK` doesn't support the `__binsparse_dlpack__` protocol.")
+
 
 def to_slice(k):
     """Convert integer indices to one-element slices for consistency"""

sparse/numba_backend/_sparse_array.py

@@ -218,6 +218,31 @@ def _str_impl(self, summary):
         except (ImportError, ValueError):
             return summary
 
+    @abstractmethod
+    def __binsparse_descriptor__(self) -> dict:
+        """Return a `dict` equivalent to a parsed JSON [`binsparse` descriptor](https://graphblas.org/binsparse-specification/#descriptor)
+        of this array.
+
+        Returns
+        -------
+        dict
+            Parsed `binsparse` descriptor.
+        """
+        raise NotImplementedError
+
+    @abstractmethod
+    def __binsparse_dlpack__(self) -> dict[str, np.ndarray]:
+        """A `dict` containing the constituent arrays of this sparse array. The keys are compatible with the
+        [`binsparse`](https://graphblas.org/binsparse-specification/) scheme, and the values are [`__dlpack__`](https://data-apis.org/array-api/latest/API_specification/generated/array_api.array.__dlpack__.html)
+        compatible objects.
+
+        Returns
+        -------
+        dict[str, np.ndarray]
+            The constituent arrays.
+        """
+        raise NotImplementedError
+
     @abstractmethod
     def asformat(self, format):
         """