Implement dpnp.interp()

[vlad-perevezentsev]

This PR suggests adding an implementation of dpnp.interp() with sycl_kernel including support for all function arguments.

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[github-actions]

Array API standard conformance tests for dpnp=0.18.0dev1=py312he4f9c94_56 ran successfully.
Passed: 1222
Failed: 0
Skipped: 9

[coveralls]

coverage: 72.039% (-0.2%) from 72.271%
when pulling 62802f8 on impl_of_interp
into 6a81e55 on master.

[github-actions]

View rendered docs @ https://intelpython.github.io/dpnp/pull/2417/index.html

[antonwolfy]

I guess the result has at least default real floating data type, isn't it?

Suggested change

	out_dtype = dpnp.common_type(x, xp, fp)
	out_dtype = dpnp.common_type(x_float_type, fp)

[vlad-perevezentsev]

dpnp.common_type takes *arrays as input argument and I can not pass x_float_type

[antonwolfy]

That check leads to SYCL queue synchronization. Is that expected?

[AlexanderKalistratov]

This implementation has a problem of not supporting const std::complex<T> case.

Better approach could be something like:

template<typename T, bool hasValueType>
struct value_type_of_impl;

template<typename T>
struct value_type_of_impl<T, false>
{
    using type = T;
};

template<typename T>
struct value_type_of_impl<T, true>
{
    using type = typename T::value_type;
};

template<T>
using value_type_of = value_type_of_impl<T, is_complex_v<T>>;

template<T>
using value_type_of_t = typename value_type_of<T>::type;

And in future is_complex could be replaced with proper has_value_type if needed.

[vlad-perevezentsev]

That is good point but I would prefer using type = typename std::remove_cv_t<T>::value_type to ensure it works correctly with const types

[antonwolfy]

Do you mean something like?

struct value_type_of<std::complex<T>>
{
    using type = typename std::remove_cv_t<T>::value_type;
};

Then, I believe, it will not work.

[vlad-perevezentsev]

I actually meant removing const in value_type_of_impl<T, true>

template<typename T>
struct value_type_of_impl<T, true>
{
    using type = typename std::remove_cv_t<T>::value_type;
};

[vlad-perevezentsev]

Done in 9e06cc3