derivative_eval -> param_shift

symmer/evolution/variational_optimization.py

@@ -240,7 +240,7 @@ class ADAPT_VQE(VQE_Driver):
     # method by which to calculate the operator pool derivatives, either
     # commutators: compute the commutator of the observable with each pool element
     # param_shift: use the parameter shift rule, requiring two expectation values per derivative
-    derivative_eval = 'commutators'
+    derivative_eval = 'param_shift'
     # we have alost implemented TETRIS-ADAPT-VQE as per https://doi.org/10.48550/arXiv.2209.10562
     # that aims to reduce circuit-depth in the ADAPT routine by adding multiple excitation terms
     # per cycle that are supported on distinct qubit positions.