Solve issue #503

Author: lshaw8317

src/blosc2/lazyexpr.py

@@ -2713,8 +2713,9 @@ def find_args(expr):
 
         return value, expression[idx:idx2]
 
-    def _compute_expr(self, item, kwargs):  # noqa : C901
         # ne_evaluate will need safe_blosc2_globals for some functions (e.g. clip, logaddexp)
+
+    def _compute_expr(self, item, kwargs):  # noqa : C901
         # that are implemenetd in python-blosc2 not in numexpr
         global safe_blosc2_globals
         if len(safe_blosc2_globals) == 0:
@@ -2748,10 +2749,11 @@ def _compute_expr(self, item, kwargs):  # noqa : C901
                         where_x = self._where_args["_where_x"]
                         where_y = self._where_args["_where_y"]
                         return np.where(lazy_expr, where_x, where_y)[key]
-                if hasattr(self, "_output"):
+                out = kwargs.get("_output", None)
+                if out is not None:
                     # This is not exactly optimized, but it works for now
-                    self._output[:] = lazy_expr[key]
-                    return self._output
+                    out[:] = lazy_expr[key]
+                    return out
                 arr = lazy_expr[key]
                 if builtins.sum(mask) > 0:
                     # Correct shape to adjust to NumPy convention
@@ -2820,11 +2822,11 @@ def sort(self, order: str | list[str] | None = None) -> blosc2.LazyArray:
 
     def compute(self, item=(), **kwargs) -> blosc2.NDArray:
         # When NumPy ufuncs are called, the user may add an `out` parameter to kwargs
-        if "out" in kwargs:
+        if "out" in kwargs:  # use provided out preferentially
             kwargs["_output"] = kwargs.pop("out")
-            self._output = kwargs["_output"]
-        if hasattr(self, "_output"):
+        elif hasattr(self, "_output"):
             kwargs["_output"] = self._output
+
         if "ne_args" in kwargs:
             kwargs["_ne_args"] = kwargs.pop("ne_args")
         if hasattr(self, "_ne_args"):

tests/ndarray/test_lazyexpr.py

@@ -1731,8 +1731,18 @@ def test_lazylinalg():
 
 # Test for issue #503 (LazyArray.compute() should honor out param)
 def test_lazyexpr_compute_out():
+    # check reductions
     a = blosc2.ones(10)
     out = blosc2.zeros(1)
     lexpr = blosc2.lazyexpr("sum(a)")
     assert lexpr.compute(out=out) is out
     assert out[0] == 10
+    assert lexpr.compute() is not out
+
+    # check normal expression
+    a = blosc2.ones(10)
+    out = blosc2.zeros(10)
+    lexpr = blosc2.lazyexpr("sin(a)")
+    assert lexpr.compute(out=out) is out
+    assert out[0] == np.sin(1)
+    assert lexpr.compute() is not out