corrected GPU logic

ptbrown1729 · ptbrown1729 · commit 7a601a1ee866 · 2023-04-27T13:56:02.000-07:00
diff --git a/mcsim/analysis/sim_reconstruction.py b/mcsim/analysis/sim_reconstruction.py
@@ -354,7 +354,7 @@ def __init__(self,
         # GPU
         # #############################################
         self.use_gpu = use_gpu
-        if not _cupy_available:
+        if self.use_gpu and not _cupy_available:
             raise ValueError("'use_gpu' was true, but CuPy could not be imported")
 
         # #############################################
