Created by: 131250208

trainer里的predict是可以不传入output_dir并将results返回的，但是predict函数是调用分类头里的后处理函数处理返回results的，而分类头里后处理函数却没有相应的处理。不传入output_dir会抛出异常。希望该函数在不传入output_dir时返回results 源码：PALM/paddlepalm/head/cls.py

def epoch_postprocess(self, post_inputs, output_dir=None):
        # there is no post_inputs needed and not declared in epoch_inputs_attrs, hence no elements exist in post_inputs
        if not self._is_training:
            if output_dir is None:
                raise ValueError('argument output_dir not found in config. Please add it into config dict/file.')
            with open(os.path.join(output_dir, 'predictions.json'), 'w') as writer:
                for i in range(len(self._preds)):
                    label = int(np.argmax(np.array(self._preds[i])))
                    result = {'index': i, 'label': label, 'logits': self._preds[i], 'probs': self._probs[i]}
                    result = json.dumps(result)
                    writer.write(result+'\n')
            print('Predictions saved at '+os.path.join(output_dir, 'predictions.json'))

其他head的后处理函数也有相同的问题，建议都修改一下，谢谢。