Make SystemY return sparse array directly; make some other scripts actual "tests"

Author: PMeira

altdss/AltDSS.py

@@ -273,11 +273,12 @@ def SystemY(self, dense=False) -> ComplexArray:
             res = None
         else:
             # return as (data, indices, indptr) that can fed into scipy.sparse.csc_matrix
-            res = (
+            from scipy.sparse import csc_matrix
+            return csc_matrix((
                 np.frombuffer(ffi.buffer(cValsPtr[0], nNz[0] * 16), dtype=complex).copy(),
                 np.frombuffer(ffi.buffer(RowIdxPtr[0], nNz[0] * 4), dtype=np.int32).copy(),
                 np.frombuffer(ffi.buffer(ColPtr[0], (nBus[0] + 1) * 4), dtype=np.int32).copy()
-            )
+            ))
 
         self._lib.DSS_Dispose_PInteger(ColPtr)
         self._lib.DSS_Dispose_PInteger(RowIdxPtr)

docs/changelog.md

@@ -5,6 +5,7 @@ relevant. See [DSS C-API's repository](https://github.com/dss-extensions/dss_cap
 
 ## 0.2.2
 
+- SystemY: in `AltDSS.SystemY`, return the matrix as a SciPy sparse matrix directly.
 - CircuitElement/CircuitElementBatch: Complement doc strings; fix some type hints.
 - CircuitElementBatch: 
     - Fix `MaxCurrent`. This will require the backend to be updated to v0.14.3.