Unable to cast Python instance to C++ type

[zhangyushan223706]

   1）aistudio
   2）v100
   3）paddle 1.8.0

• 复现信息：
  ack (most recent call last) in
  156 avg_loss.backward()
  157
  --> 158 optimizer.minimize(avg_loss,parameter_list=track.parameters())
  159
  160
  </opt/conda/envs/python35-paddle120-env/lib/python3.7/site-packages/decorator.py:decorator-gen-185> in minimize(self, loss, startup_program, parameter_list, no_grad_set)
  /opt/conda/envs/python35-paddle120-env/lib/python3.7/site-packages/paddle/fluid/dygraph/base.py in impl(func, *args, **kwargs)
  201 def impl(func, *args, **kwargs):
  202 with switch_tracer_mode_guard(is_train=False):
  --> 203 return func(*args, **kwargs)
  204
  205 return impl(func)
  /opt/conda/envs/python35-paddle120-env/lib/python3.7/site-packages/paddle/fluid/optimizer.py in minimize(self, loss, startup_program, parameter_list, no_grad_set)
  835
  836 optimize_ops = self.apply_optimize(
  --> 837 loss, startup_program=startup_program, params_grads=params_grads)
  838
  839 return optimize_ops, params_grads
  /opt/conda/envs/python35-paddle120-env/lib/python3.7/site-packages/paddle/fluid/optimizer.py in apply_optimize(self, loss, startup_program, params_grads)
  745 params_grads = append_regularization_ops(params_grads,
  746 self.regularization)
  --> 747 optimize_ops = self._create_optimization_pass(params_grads)
  748 else:
  749 program = loss.block.program
  /opt/conda/envs/python35-paddle120-env/lib/python3.7/site-packages/paddle/fluid/optimizer.py in _create_optimization_pass(self, parameters_and_grads)
  549 continue
  550 if param_and_grad[0].trainable is True:
  --> 551 self._append_optimize_op(target_block, param_and_grad)
  552 else:
  553 for param_and_grad in parameters_and_grads:
  /opt/conda/envs/python35-paddle120-env/lib/python3.7/site-packages/paddle/fluid/optimizer.py in _append_optimize_op(self, block, param_and_grad)
  1037 velocity_acc = self._get_accumulator(self._velocity_acc_str,
  1038 param_and_grad[0])
  -> 1039 lr = self._create_param_lr(param_and_grad)
  1040
  1041 if framework.in_dygraph_mode():
  /opt/conda/envs/python35-paddle120-env/lib/python3.7/site-packages/paddle/fluid/optimizer.py in _create_param_lr(self, param_and_grad)
  386 is_with_opt=True), framework.name_scope(
  387 'scale_with_param_lr'):
  --> 388 return self._global_learning_rate() * param_lr
  389
  390 def _create_accumulators(self, block, parameters):
  /opt/conda/envs/python35-paddle120-env/lib/python3.7/site-packages/paddle/fluid/dygraph/math_op_patch.py in impl(self, other_var)
  184 else:
  185 # add fill_op
  --> 186 other_var = create_scalar(value=other_var, dtype=lhs_dtype)
  187
  188 rhs_dtype = safe_get_dtype(other_var)
  /opt/conda/envs/python35-paddle120-env/lib/python3.7/site-packages/paddle/fluid/dygraph/math_op_patch.py in create_scalar(value, dtype)
  50
  51 def create_scalar(value, dtype):
  ---> 52 return create_tensor(value, dtype, shape=[1])
  53
  54 def astype(self, dtype):
  </opt/conda/envs/python35-paddle120-env/lib/python3.7/site-packages/decorator.py:decorator-gen-198> in create_tensor(value, dtype, shape)
  /opt/conda/envs/python35-paddle120-env/lib/python3.7/site-packages/paddle/fluid/dygraph/base.py in impl(func, *args, **kwargs)
  201 def impl(func, *args, **kwargs):
  202 with switch_tracer_mode_guard(is_train=False):
  --> 203 return func(*args, **kwargs)
  204
  205 return impl(func)
  /opt/conda/envs/python35-paddle120-env/lib/python3.7/site-packages/paddle/fluid/dygraph/math_op_patch.py in create_tensor(value, dtype, shape)
  45 out = _varbase_creator(dtype=dtype)
  46 out = core.ops.fill_constant(out, 'dtype', dtype, 'shape', shape,
  ---> 47 'value', value, 'force_cpu', False)
  48 out.stop_gradient = True
  49 return out
  RuntimeError: Unable to cast Python instance to C++ type (compile in debug mode for details)
  ack (most recent call last) in
  156 avg_loss.backward()
  157
  --> 158 optimizer.minimize(avg_loss,parameter_list=track.parameters())
  159
  160
  </opt/conda/envs/python35-paddle120-env/lib/python3.7/site-packages/decorator.py:decorator-gen-185> in minimize(self, loss, startup_program, parameter_list, no_grad_set)
  /opt/conda/envs/python35-paddle120-env/lib/python3.7/site-packages/paddle/fluid/dygraph/base.py in impl(func, *args, **kwargs)
  201 def impl(func, *args, **kwargs):
  202 with switch_tracer_mode_guard(is_train=False):
  --> 203 return func(*args, **kwargs)
  204
  205 return impl(func)
  /opt/conda/envs/python35-paddle120-env/lib/python3.7/site-packages/paddle/fluid/optimizer.py in minimize(self, loss, startup_program, parameter_list, no_grad_set)
  835
  836 optimize_ops = self.apply_optimize(
  --> 837 loss, startup_program=startup_program, params_grads=params_grads)
  838
  839 return optimize_ops, params_grads
  /opt/conda/envs/python35-paddle120-env/lib/python3.7/site-packages/paddle/fluid/optimizer.py in apply_optimize(self, loss, startup_program, params_grads)
  745 params_grads = append_regularization_ops(params_grads,
  746 self.regularization)
  --> 747 optimize_ops = self._create_optimization_pass(params_grads)
  748 else:
  749 program = loss.block.program
  /opt/conda/envs/python35-paddle120-env/lib/python3.7/site-packages/paddle/fluid/optimizer.py in _create_optimization_pass(self, parameters_and_grads)
  549 continue
  550 if param_and_grad[0].trainable is True:
  --> 551 self._append_optimize_op(target_block, param_and_grad)
  552 else:
  553 for param_and_grad in parameters_and_grads:
  /opt/conda/envs/python35-paddle120-env/lib/python3.7/site-packages/paddle/fluid/optimizer.py in _append_optimize_op(self, block, param_and_grad)
  1037 velocity_acc = self._get_accumulator(self._velocity_acc_str,
  1038 param_and_grad[0])
  -> 1039 lr = self._create_param_lr(param_and_grad)
  1040
  1041 if framework.in_dygraph_mode():
  /opt/conda/envs/python35-paddle120-env/lib/python3.7/site-packages/paddle/fluid/optimizer.py in _create_param_lr(self, param_and_grad)
  386 is_with_opt=True), framework.name_scope(
  387 'scale_with_param_lr'):
  --> 388 return self._global_learning_rate() * param_lr
  389
  390 def _create_accumulators(self, block, parameters):
  /opt/conda/envs/python35-paddle120-env/lib/python3.7/site-packages/paddle/fluid/dygraph/math_op_patch.py in impl(self, other_var)
  184 else:
  185 # add fill_op
  --> 186 other_var = create_scalar(value=other_var, dtype=lhs_dtype)
  187
  188 rhs_dtype = safe_get_dtype(other_var)
  /opt/conda/envs/python35-paddle120-env/lib/python3.7/site-packages/paddle/fluid/dygraph/math_op_patch.py in create_scalar(value, dtype)
  50
  51 def create_scalar(value, dtype):
  ---> 52 return create_tensor(value, dtype, shape=[1])
  53
  54 def astype(self, dtype):
  </opt/conda/envs/python35-paddle120-env/lib/python3.7/site-packages/decorator.py:decorator-gen-198> in create_tensor(value, dtype, shape)
  /opt/conda/envs/python35-paddle120-env/lib/python3.7/site-packages/paddle/fluid/dygraph/base.py in impl(func, *args, **kwargs)
  201 def impl(func, *args, **kwargs):
  202 with switch_tracer_mode_guard(is_train=False):
  --> 203 return func(*args, **kwargs)
  204
  205 return impl(func)
  /opt/conda/envs/python35-paddle120-env/lib/python3.7/site-packages/paddle/fluid/dygraph/math_op_patch.py in create_tensor(value, dtype, shape)
  45 out = _varbase_creator(dtype=dtype)
  46 out = core.ops.fill_constant(out, 'dtype', dtype, 'shape', shape,
  ---> 47 'value', value, 'force_cpu', False)
  48 out.stop_gradient = True
  49 return out
  RuntimeError: Unable to cast Python instance to C++ type (compile in debug mode for details)

[zhangyushan223706]

动态图编程，优化时报错，怎么解决？

[juncaipeng]

可以将代码贴一下吗？从log无法明确出来问题，可能是用法有误。

[zhangyushan223706]

主要是对paddle.layers运算进行了再次函数封装

[zhangyushan223706]

应该怎么进行封装运算？

[juncaipeng]

正常封装是可以的，但是底层还是必须符合paddle api的规范哦。