add NotImplementedError for multi optimizers (#22181)

* add NotImplementedError for multi optimizers used on multi-places . test=develop

* assert error only if num_devices>1. test=develop

* set test_optimizer_in_control_flow in CMakeLists for using multi-GPU.test=develop

python/paddle/fluid/compiler.py

@@ -62,6 +62,28 @@ def _prune_feed_ops(program):
         program.global_block()._remove_op(index)
 
 
+def _has_optimize_op(block):
+    for op in block.ops:
+        op_maker = core.op_proto_and_checker_maker
+        optimize = core.op_proto_and_checker_maker.OpRole.Optimize
+        if op_maker.kOpRoleVarAttrName() in op.attr_names and \
+                int(op.all_attrs()[op_maker.kOpRoleAttrName()]) == int(optimize):
+            return True
+    return False
+
+
+def _has_optimizer_in_control_flow(program):
+    if not program:
+        program = framework.default_main_program()
+    for op in program.global_block().ops:
+        if op.type == "conditional_block_grad":
+            sub_block = program.block(op._block_attr_id("sub_block"))
+            if _has_optimize_op(sub_block):
+                return True
+
+    return False
+
+
 class CompiledProgram(object):
     """
     The CompiledProgram is used to transform a program or graph for
@@ -386,6 +408,16 @@ class CompiledProgram(object):
                 self._places = self._get_places(self._place, self._places)
             else:
                 self._places = [self._place]
+
+            # Todo(liym27):If optimizer is used in control flow,
+            #  training on multi-places is not supported now, will
+            #  be supported later.
+            if len(self._places) > 1 and \
+                    _has_optimizer_in_control_flow(self._program):
+                raise NotImplementedError(
+                    "If optimizer is used in control flow, "
+                    "training on multi-places is not supported now.")
+
             self._executor = self._compile_data_parallel(
                 use_cuda=isinstance(self._place, core.CUDAPlace),
                 scope=self._scope,

python/paddle/fluid/tests/unittests/CMakeLists.txt

@@ -333,4 +333,5 @@ set_tests_properties(test_parallel_executor_test_while_train test_parallel_execu
         test_parallel_executor_feed_persistable_var
         test_parallel_executor_crf_auto_growth test_buffer_shared_memory_reuse_pass_and_fuse_optimization_op_pass
         test_data_norm_op test_imperative_using_non_zero_gpu test_fuse_bn_act_pass
+        test_optimizer_in_control_flow
         test_buffer_shared_memory_reuse_pass PROPERTIES LABELS "RUN_TYPE=DIST")

python/paddle/fluid/tests/unittests/test_optimizer_in_control_flow.py

@@ -22,6 +22,8 @@ import paddle.fluid.layers as layers
 import paddle.fluid.optimizer as optimizer
 from paddle.fluid.framework import Program, program_guard
 import paddle.fluid.core as core
+import paddle.fluid.compiler as compiler
+import os
 
 BATCH_SIZE = 1
 INPUT_SIZE = 784
@@ -106,7 +108,7 @@ def static(train_data,
 
     place = fluid.CUDAPlace(0) if use_cuda else fluid.CPUPlace()
     exe = fluid.Executor(place)
-        exe.run(fluid.default_startup_program())
+    exe.run(startup_program)
 
     for epoch in range(EPOCH_NUM):
         feed_image, feed_label = train_data[epoch]
@@ -225,5 +227,58 @@ class TestMultiTask(unittest.TestCase):
                                                                    loss_2))
 
 
+class TestMultiOptimizersMultiCardsError(unittest.TestCase):
+    def test_error(self):
+        startup_program = Program()
+        main_program = Program()
+        use_cuda = core.is_compiled_with_cuda()
+        with program_guard(main_program, startup_program):
+
+            def fn_1(opt, avg_loss):
+                opt.minimize(avg_loss)
+
+            def fn_2(opt, avg_loss):
+                opt.minimize(avg_loss)
+
+            x = fluid.layers.data("X", [10], 'float32')
+            hidden = layers.fc(x, 5)
+            avg_loss = layers.mean(hidden)
+
+            adam = optimizer.Adam(learning_rate=LR)
+            sgd = optimizer.SGD(learning_rate=LR)
+
+            cond = layers.fill_constant([1], 'bool', True)
+
+            layers.case([(cond, lambda: fn_1(adam, avg_loss))],
+                        lambda: fn_2(sgd, avg_loss))
+
+        cpu_place = fluid.CPUPlace()
+        cuda_place = fluid.CUDAPlace(0) if use_cuda else fluid.CPUPlace()
+
+        for place in [cpu_place, cuda_place]:
+
+            exe = fluid.Executor(place)
+            exe.run(startup_program)
+
+            np.random.seed(SEED)
+            os.environ['CPU_NUM'] = str(2)
+            pe_exe = fluid.ParallelExecutor(
+                use_cuda=use_cuda,
+                main_program=main_program,
+                loss_name=avg_loss.name)
+            num_devices = pe_exe.device_count
+
+            def not_implemented_error():
+                pe_exe.run(feed={
+                    'X': np.random.random(size=[64, 10]).astype('float32'),
+                },
+                           fetch_list=[avg_loss.name])
+
+            if num_devices > 1:
+                self.assertRaises(NotImplementedError, not_implemented_error)
+            else:
+                not_implemented_error()
+
+
 if __name__ == '__main__':
     unittest.main()