Solution: warning:tensorflow:gradients do not exist for variables ['deny_1/kernel:0', 'deny_1/bias:0',

Project scenario ：

tensorflow Deep learning training

Problem description ：

Complete error report ：

WARNING:tensorflow:Gradients do not exist for variables ['dense_1/kernel:0', 'dense_1/bias:0', 'dense_2/kernel:0', 'dense_2/bias:0', 'diffusion_writer/conv_sub_layer/affine_transform_layer/dense_3/kernel:0', 'diffusion_writer/conv_sub_layer/affine_transform_layer/dense_3/bias:0', 'diffusion_writer/conv_sub_layer/affine_transform_layer/dense_4/kernel:0', 'diffusion_writer/conv_sub_layer/affine_transform_layer/dense_4/bias:0', 'diffusion_writer/conv_sub_layer/affine_transform_layer_1/dense_5/kernel:0', 'diffusion_writer/conv_sub_layer/affine_transform_layer_1/dense_5/bias:0', 'diffusion_writer/conv_sub_layer/affine_transform_layer_1/dense_6/kernel:0', 'diffusion_writer/conv_sub_layer/affine_transform_layer_1/de