Move to test on GPU

examples/GPU/example_learn_samples.py

@@ -47,7 +47,7 @@ def __init__(self, inital_trajectory):
             data=torch.Tensor(inital_trajectory),
             requires_grad=True,
         )
-        self.operator = get_operator("gpunufft", wrt_data=True, wrt_traj=True)(
+        self.operator = get_operator("cufinufft", wrt_data=True, wrt_traj=True)(
             self.trajectory.detach().cpu().numpy(),
             shape=(256, 256),
             density=True,