Numpy 2.3 fix (tostring -> tobytes) (#793)

Author: IAlibay

openmmtools/multistate/multistatereporter.py

@@ -1091,7 +1091,7 @@ def read_dict(self, path: str) -> Union[dict, Any]:
             if nc_element.dtype == 'S1':
                 # Handle variables stored in fixed_dimensions
                 data_chars = nc_element[:]
-                data_str = data_chars.tostring().decode()
+                data_str = data_chars.tobytes().decode()
             else:
                 data_str = str(nc_element[0])
             data = yaml.load(data_str, Loader=_DictYamlLoader)

openmmtools/tests/test_sampling.py

@@ -584,7 +584,7 @@ def decompact_state_variable(variable):
                 if variable.dtype == "S1":
                     # Handle variables stored in fixed_dimensions
                     data_chars = variable[:]
-                    data_str = data_chars.tostring().decode()
+                    data_str = data_chars.tobytes().decode()
                 else:
                     data_str = str(variable[0])
                 return data_str