theano gpu无法在Google colab上运行

Question

我正在尝试使用Google colab在gpu上运行theano代码，但是它不起作用。这是我的代码，该代码是从Tutorial中提取的，预计在输出时Used the gpu会打印出Used the cpu。我使用这个Stack overflow问题在运行时模式下配置gpu。这是我的代码，它已经输出：

（以防万一，我已将笔记本配置为使用GPU ）

代码：

import os
os.environ["THEANO_FLAGS"] = "mode=FAST_RUN,device=gpu,floatX=float32"
import theano


from theano import function, config, shared, tensor
import numpy
import time

vlen = 10 * 30 * 768  # 10 x #cores x # threads per core
iters = 1000

rng = numpy.random.RandomState(22)
x = shared(numpy.asarray(rng.rand(vlen), config.floatX))
f = function([], tensor.exp(x))
print(f.maker.fgraph.toposort())
t0 = time.time()
for i in range(iters):
    r = f()
t1 = time.time()
print("Looping %d times took %f seconds" % (iters, t1 - t0))
print("Result is %s" % (r,))
if numpy.any([isinstance(x.op, tensor.Elemwise) and
              ('Gpu' not in type(x.op).__name__)
              for x in f.maker.fgraph.toposort()]):
    print('Used the cpu')
else:
    print('Used the gpu')

未放置：

[Elemwise{exp,no_inplace}(<TensorType(float64, vector)>)]
Looping 1000 times took 4.432506 seconds
Result is [1.23178032 1.61879341 1.52278065 ... 2.20771815 2.29967753 1.62323285]
Used the cpu