Complex Tensor in C++ API?

Hi everyone,

I am currently trying to integrate PyTorch into my project on c++ side. I notice that It seems there is no complex type similarity of k (ex: kfloat…), but the pytorch implementation does have complex…

I am wondering if it is possible to initialize a complex type tensor/scalar/storage?

The complex type is implemented as kComplexHalf, kComplexFloat, and kComplexDouble as seen here.

Thanks, I was wondering how to create an Scalar with complex64 dtype in C++, can you give me an example, e.g.

a = 3+5j

Somthing like this?

This should work:

tensor = at::tensor(c10::complex<float>(1.0, 2.0), at::dtype(at::kComplexFloat))
1 Like

Thanks, I only want to get the Scalar, not Scalar to tensor. So basically just do this?

auto base = c10::Scalar(c10::complex<double>(1.0, 2.0));

Is this equivilent to the python code of:

base = 1.0 + 2.0j;

Since the default dtype for scalar is double not float.

Another question is that, when I try to print out the complex tensor using the std::cout method, the imaginary part didn’t get printed out.
Here is a simple example:

auto a = at::tensor({c10::complex<double>(1, 0.5), c10::complex<double>(1, 0.5)}, at::dtype(at::kComplexFloat));

    std::cout << a << std::endl;

What I got:

[W Copy.cpp:219] Warning: Casting complex values to real discards the imaginary part (function operator())

So, how can I print out the value of a complex tensor including the imaginary part?
Much appreciated.