Merge branch 'main' of github.com:Blosc/python-blosc2

Author: lshaw8317

src/blosc2/lazyexpr.py

@@ -3121,13 +3121,16 @@ def _new_expr(cls, expression, operands, guess, out=None, where=None, ne_args=No
             # substitutes with dummy operands (cheap for reductions) and
             # defaults to blosc2 functions (cheap for constructors)
             new_expr = _numpy_eval_expr(desliced_expr, desliced_ops, prefer_blosc=True)
-            _dtype = new_expr.dtype
+            _dtype = new_expr.dtype if hasattr(new_expr, "dtype") else np.dtype(type(new_expr))
             if isinstance(new_expr, blosc2.LazyExpr):
                 # DO NOT restore the original expression and operands
                 # Instead rebase operands and restore only constructors
                 expression_, operands_ = conserve_functions(
                     _expression, _operands, new_expr.operands | local_vars
                 )
+            elif _shape == () and not _operands:  # passed scalars
+                expression_ = "o0"
+                operands_ = {"o0": ne_evaluate(_expression)}
             else:
                 # An immediate evaluation happened
                 # (e.g. all operands are numpy arrays or constructors)

tests/conftest.py

@@ -6,6 +6,7 @@
 # LICENSE file in the root directory of this source tree)
 #######################################################################
 import os
+import sys
 
 import pytest
 
@@ -14,6 +15,15 @@
 
 def pytest_configure(config):
     blosc2.print_versions()
+    if sys.platform != "emscripten":
+        # Using the defaults for nthreads can be very time consuming for tests.
+        # Fastest runtime (95 sec) for the whole test suite (Mac Mini M4 Pro)
+        # blosc2.set_nthreads(1)
+        # Second best runtime (101 sec), but still contained, and
+        # actually tests multithreading.
+        blosc2.set_nthreads(2)
+        # This makes the worst time (242 sec)
+        # blosc2.set_nthreads(blosc2.nthreads)  # worst runtime ()
 
 
 @pytest.fixture(scope="session")