tensorflow - 凯拉斯 TPU。编译失败 : Detected unsupported operations

Question

我尝试使用 Google Colab TPU 运行我的 keras UNet 模型，但我遇到了这个问题 UpSampling2D .任何解决方案或解决方法？

要运行的代码:

import os
import numpy as np
import tensorflow as tf
from tensorflow.keras.models import Sequential
from tensorflow.keras.layers import UpSampling2D

model = Sequential()
model.add(UpSampling2D((2, 2), input_shape=(16, 16, 1)))
model.compile(optimizer=tf.train.RMSPropOptimizer(learning_rate=0.01), 
              loss='binary_crossentropy', metrics=['acc'])

TPU_WORKER = 'grpc://' + os.environ['COLAB_TPU_ADDR']
tf.logging.set_verbosity(tf.logging.INFO)


model = tf.contrib.tpu.keras_to_tpu_model(
    model,strategy=tf.contrib.tpu.TPUDistributionStrategy(
        tf.contrib.cluster_resolver.TPUClusterResolver(TPU_WORKER)))

X = np.zeros((1024, 16, 16, 1))
Y = np.zeros((1024, 32, 32, 1))

model.fit(X, Y, batch_size=1024)

错误:

RuntimeError: Compilation failed: Compilation failure: Detected unsupported operations when trying to compile graph cluster_3_5095732716396540171[] on XLA_TPU_JIT: ResizeNearestNeighbor (No registered 'ResizeNearestNeighbor' OpKernel for XLA_TPU_JIT devices compatible with node {{node tpu_140211339657168/up_sampling2d_1/ResizeNearestNeighbor}} = ResizeNearestNeighbor[T=DT_FLOAT, align_corners=false, _device="/device:TPU_REPLICATED_CORE"](infeed-train_1:1, tpu_140211339657168/up_sampling2d_1/mul) . Registered: device='CPU'; T in [DT_DOUBLE] device='CPU'; T in [DT_FLOAT] device='CPU'; T in [DT_BFLOAT16] device='CPU'; T in [DT_HALF] device='CPU'; T in [DT_INT8] device='CPU'; T in [DT_UINT8] device='CPU'; T in [DT_INT16] device='CPU'; T in [DT_UINT16] device='CPU'; T in [DT_INT32] device='CPU'; T in [DT_INT64] ){{node tpu_140211339657168/up_sampling2d_1/ResizeNearestNeighbor}}

Answer 1

从错误来看，Keras 的 Tensorflow 后端 ( ResizeNearestNeighbor ) 图中的一项操作目前与 TPU 不兼容。目前有少量 Tensorflow 操作不适用于 TPU ( Cloud TPU FAQs )。

您可以查看与 TPU 兼容的 Tensorflow ops 的当前列表 here .你也可以使用 Tensorboard 查看 TPU Compatibility Graphs .

作为一种解决方法，您可以尝试结合 TPU 兼容的 Tensorflow 操作来复制 ResizeNearestNeighbor 的行为。 .特别是，您可能对 ResizeBilinear 感兴趣Op，它与 TPU 兼容。