              else:
                  self._validate_input_shape()
                  inputs = self._get_inputs()
                  self._model = self.build_model(inputs)
              if not is_summary and not self._is_predict:
                  self._compile_model()
              self._output_summary()
  
 
</s> remove         self._use_mixed_precision = self._set_keras_mixed_precision(use_mixed_precision,
                                                                    bool(arguments.exclude_gpus))
 </s> add         self._use_mixed_precision = self._set_keras_mixed_precision(use_mixed_precision)
        if self._use_mixed_precision:
            logger.info("Enabling Mixed Precision Training.") </s> remove         logger.info("Enabling Mixed Precision Training.")
 </s> add         if not use_mixed_precision:
            policy = mixedprecision.Policy('float32')
            mixedprecision.set_global_policy(policy)
            logger.debug("Disabling mixed precision. (Compute dtype: %s, variable_dtype: %s)",
                         policy.compute_dtype, policy.variable_dtype)
            return False
                if not self._settings.use_mixed_precision:
                    # Store layer names which can be switched to mixed precision
                    self._state.add_mixed_precision_layers(
                        self._settings.get_mixed_precision_layers(self.build_model, inputs))
              else:
                  self._validate_input_shape()
                  inputs = self._get_inputs()
                if not self._settings.use_mixed_precision:
                    # Store layer names which can be switched to mixed precision
                    self._state.add_mixed_precision_layers(
                        self._settings.get_mixed_precision_layers(self.build_model, inputs))
                  self._model = self.build_model(inputs)
              if not is_summary and not self._is_predict:
                  self._compile_model()
              self._output_summary()
  
keep keep add keep keep keep keep keep
 Enable change of precision for existing models 
plugins/train/model/_base/model.py