"reshape()" function in Eigen tensor does not compile - c++

Question

I want to use "reshape()" fuction in Eigen unsupported tensor, but my source code cannot be compiled.
The compilation was done as follows.
g++ -std=c++14 -I (path to Eigen) eigen_practice.cpp -o eigen_practice
and here is my source code.
# include "unsupported/Eigen/CXX11/Tensor"
using namespace Eigen;
int main(){
　Tensor<float, 2> input(7, 11);
　Eigen::array<int, 3> three_dims{{7, 11, 1}};
　Tensor<float, 3> result = input.reshape(three_dims);
　return 0;
}
And here is the error messeage.
In file included from eigen_practice.cpp:12:
In file included from /Users/yamamototatsuto/Dropbox/include_for_C++/eigen/unsupported/Eigen/CXX11/Tensor:145:
/Users/yamamototatsuto/Dropbox/include_for_C++/eigen/unsupported/Eigen/CXX11/src/Tensor/Tensor.h:397:7: error:
no matching member function for call to 'resize'
resize(TensorEvaluator<const Assign, DefaultDevice>(assign, Defaul...
^~~~~~
eigen_practice.cpp:63:28: note: in instantiation of function template
specialization 'Eigen::Tensor<float, 3, 0,
long>::Tensor<Eigen::TensorReshapingOp<const std::__1::array<int, 3>,
Eigen::Tensor<float, 2, 0, long> > >' requested here
Tensor<float, 3> result = input.reshape(three_dims);
^
/Users/yamamototatsuto/Dropbox/include_for_C++/eigen/unsupported/Eigen/CXX11/src/Tensor/Tensor.h:423:10: note:
candidate function template not viable: no known conversion from 'const
Eigen::TensorEvaluator<const Eigen::TensorAssignOp<Eigen::Tensor<float, 3,
0, long>, const Eigen::TensorReshapingOp<const std::__1::array<int, 3>,
Eigen::Tensor<float, 2, 0, long> > >, Eigen::DefaultDevice>::Dimensions'
(aka 'const std::__1::array<int, 3>') to 'Eigen::Tensor<float, 3, 0,
long>::Index' (aka 'long') for 1st argument
void resize(Index firstDimension, IndexTypes... otherDimensions)
^
/Users/yamamototatsuto/Dropbox/include_for_C++/eigen/unsupported/Eigen/CXX11/src/Tensor/Tensor.h:432:28: note:
candidate function not viable: no known conversion from
'array<int, [...]>' to 'const array<long, [...]>' for 1st argument
EIGEN_DEVICE_FUNC void resize(const array<Index, NumIndices>& dimensions)
^
/Users/yamamototatsuto/Dropbox/include_for_C++/eigen/unsupported/Eigen/CXX11/src/Tensor/Tensor.h:450:28: note:
candidate function not viable: no known conversion from 'const
Eigen::TensorEvaluator<const Eigen::TensorAssignOp<Eigen::Tensor<float, 3,
0, long>, const Eigen::TensorReshapingOp<const std::__1::array<int, 3>,
Eigen::Tensor<float, 2, 0, long> > >, Eigen::DefaultDevice>::Dimensions'
(aka 'const std::__1::array<int, 3>') to 'const
DSizes<Eigen::Tensor<float, 3, 0, long>::Index, NumIndices>' (aka 'const
DSizes<long, NumIndices>') for 1st argument
EIGEN_DEVICE_FUNC void resize(const DSizes<Index, NumIndices>& dimensions) {
^
/Users/yamamototatsuto/Dropbox/include_for_C++/eigen/unsupported/Eigen/CXX11/src/Tensor/Tensor.h:479:10: note:
candidate template ignored: could not match 'Sizes' against 'array'
void resize(const Sizes<Indices...>& dimensions) {
^
/Users/yamamototatsuto/Dropbox/include_for_C++/eigen/unsupported/Eigen/CXX11/src/Tensor/Tensor.h:459:10: note:
candidate function not viable: requires 0 arguments, but 1 was provided
void resize()
^
1 error generated.
This source code is just a copy of what is in the documentation.
(https://eigen.tuxfamily.org/dox/unsupported/eigen_tensors.html)
So it should compile, but it doesn't.
How can I solve it?
And why the error message mentions about "resize()" function?