1. 参考官方的eval.py和infer.py结合，想在exe.run的fetch_list中返回fluid.layers.detection_output的输出，报错如下：

C++ Callstacks:
Cannot find fetch variable in scope, fetch_var_name is detection_output_0.tmp_0 at [/paddle/paddle/fluid/operators/controlflow/fetch_op.cc:37]

具体代码如下：

• 在函数体中返回fluid.layers.detection_output的输出：

with fluid.program_guard(main_prog, startup_prog):

        py_reader = fluid.layers.py_reader(

            capacity=64,

            shapes=[[-1] + image_shape, [-1, 4], [-1, 1], [-1, 1]],

            lod_levels=[0, 1, 1, 1],

            dtypes=["float32", "float32", "int32", "int32"],

            use_double_buffer=True)




        image, gt_box, gt_label, difficult = fluid.layers.read_file(

                py_reader)

        locs, confs, box, box_var = build_ssd(image, num_classes,

                                                            image_shape)

        nmsed_out = fluid.layers.detection_output(

            locs, confs, box, box_var, nms_threshold=args.nms_threshold)

     

    return py_reader, nmsed_out

在测试程序调用：

def test(args, data_args, test_list, batch_size, model_dir=None):

    startup_prog = fluid.Program()

    test_prog = fluid.Program()

    test_py_reader, detection_output = build_program(

        main_prog=test_prog,

        startup_prog=startup_prog,

        args=args,

        data_args=data_args)




    place = fluid.CUDAPlace(0) if args.use_gpu else fluid.CPUPlace()

    exe = fluid.Executor(place)

    if model_dir:

        def if_exist(var):

            return os.path.exists(os.path.join(model_dir, var.name))

        fluid.io.load_vars(exe, model_dir, predicate=if_exist)

    test_reader = reader.test(data_args, test_list, batch_size=batch_size)

    test_py_reader.decorate_paddle_reader(test_reader)




    test_py_reader.start()




    # switch network to test mode (i.e. batch norm test mode)

    test_program = fluid.default_main_program().clone(for_test=True)

    detection_output_v, = exe.run(test_program,

                           fetch_list=[detection_output],

                           return_numpy=False)

以上