Fix incorrect description of SVD truncation that the sqrt() is used

Author: JanLuca

peps_ad/config.py

@@ -65,8 +65,8 @@ class PEPS_AD_Config:
       ctmrg_verbose_output (:obj:`bool`):
         Print verbose output in CTMRG routine.
       ctmrg_truncation_eps (:obj:`float`):
-        Value for cut off of singular values compared to the biggest one. Used
-        in calculation of CTMRG projectors.
+        Value for cut off of the sqrt of the  singular values compared to the
+        biggest one. Used in the calculation of the CTMRG projectors.
       ctmrg_fail_if_not_converged (:obj:`bool`):
         Flag if the CTMRG routine should fail with an error if no convergence
         can be reached within the maximal number of steps.

peps_ad/ctmrg/routine.py

@@ -402,7 +402,7 @@ def calc_ctmrg_env(
                 new_truncation_eps
                 <= peps_ad_config.ctmrg_increase_truncation_eps_max_value
             ):
-                print(f"CTMRG: Increasing SVD truncation eps to {new_truncation_eps}.")
+                print(f"CTMRG: Increasing sqrt(SVD) truncation eps to {new_truncation_eps}.")
                 peps_ad_global_state.ctmrg_effective_truncation_eps = new_truncation_eps
                 working_unitcell = unitcell
                 continue