对推力::具有推力::变换的复杂类型进行操作 [英] Operating on thrust::complex types with thrust::transform

问题描述

我正在尝试使用 thrust :: transform 对类型为 thrust：complex< float> 没有成功。以下示例在编译过程中因几页错误而崩溃。

I'm trying to use thrust::transform to operate on vectors of type thrust:complex<float> without success. The following example blows up during compilation with several pages of errors.

#include <cuda.h>
#include <cuda_runtime.h>
#include <cufft.h>

#include <thrust/device_vector.h>
#include <thrust/host_vector.h>
#include <thrust/transform.h>
#include <thrust/complex.h>

int main(int argc, char *argv[]) {

  thrust::device_vector< thrust::complex<float> > d_vec1(4);
  thrust::device_vector<float> d_vec2(4);

  thrust::fill(d_vec1.begin(), d_vec1.end(), thrust::complex<float>(1,1));

  thrust::transform(d_vec1.begin(), d_vec1.end(), d_vec2.begin(), thrust::abs< thrust::complex<float> >() );
}

我在Ubuntu Xenial上使用CUDA 8.0并使用clang 3.8.0进行编译-2ubuntu4使用 nvcc --std = c ++ 11 main.cpp -o main 。

I'm using CUDA 8.0 on Ubuntu Xenial and compiling with clang 3.8.0-2ubuntu4 using nvcc --std=c++11 main.cpp -o main.

出现主要错误会是：

main.cpp: In function ‘int main(int, char**)’:
main.cpp:17:105: error: no matching function for call to ‘abs()’
 gin(), d_vec1.end(), d_vec2.begin(), thrust::abs< thrust::complex<float> >() );

和

/usr/local/cuda-8.0/bin/../targets/x86_64-linux/include/thrust/detail/complex/arithmetic.h:143:20: note:   template argument deduction/substitution failed:
main.cpp:17:105: note:   candidate expects 1 argument, 0 provided
 gin(), d_vec1.end(), d_vec2.begin(), thrust::abs< thrust::complex<float> >() );
                                                                            ^

在真正的浮动对象上工作没问题，但在复杂的浮动对象上却没有问题。我以为我遗漏了一个类型错误，但在很大程度上，Thrust& amp;模板。

No problem working on real floats, but no such with complex ones. I'm thinking there's a type error that I'm missing, but I'm very much still on the steep part of the learning curve with Thrust & templates.

推荐答案

错误消息具有很强的描述性：

The error message is quite descriptive:

thrust :: abs< thrust :: complex< ...>> 是函数，它期望恰好是一个参数，请参见 thrust / detail / complex / arithmetic。 h＃L143 ：

thrust::abs<thrust::complex<...>> is a function which expects exactly one parameter, see thrust/detail/complex/arithmetic.h#L143:

template <typename ValueType>
  __host__ __device__
  inline ValueType abs(const complex<ValueType>& z){
  return hypot(z.real(),z.imag());
}

对于您的用例，您需要用来包装该函数函子：

For your use case, you need to wrap that function by a functor:

struct complex_abs_functor
{
    template <typename ValueType>
    __host__ __device__
    ValueType operator()(const thrust::complex<ValueType>& z)
    {
        return thrust::abs(z);
    }
};

最后，在此处使用该仿函数：

Finally, employ that functor here:

thrust::transform(d_vec1.begin(),
                  d_vec1.end(),
                  d_vec2.begin(),
                  complex_abs_functor());

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