cuco::dynamic_map to store kv-pairs with values type of vector<float>

[iamlazy123]

I need to use cuco::dynamic_map to store kv-pairs with values type of vector or float[4]. Can anyone show me a concrete example of how to do this?

[PointKernel]

Hi @iamlazy123, thanks for reaching out! Could you share a code snippet or example showing where you're getting stuck? In the meantime, here's a reference that might help: https://godbolt.org/z/nWfcYMa4j. It demonstrates how to use cuco data structures with arbitrary key-value pairs. Feel free to let us know if you have any other questions!

[iamlazy123]

Thank you for the hint. I'll run a test on this.

[iamlazy123]

@PointKernel Help!

I followed your suggestion and used cuda::std::array<float, 4UL> as the value_type, but I found that the erase operation fails.

Here is the code:

using KeyType = int64_t;
using ValueType = cuda::std::array<float, 4UL>;

namespace cuco {
template <>
constexpr bool is_bitwise_comparable_v<ValueType> = true;
}

int main() {
    KeyType empty_key_sentinel = -1;
    ValueType empty_value_sentinel = {-1.0f, -1.0f, -1.0f, -1.0f};

    auto map = cuco::dynamic_map<KeyType, ValueType>{100000,
                                          cuco::empty_key<KeyType>{empty_key_sentinel},
                                          cuco::empty_value<ValueType>{empty_value_sentinel}};
    thrust::device_vector<KeyType> keys = {1, 2, 3, 4, 5};

    // Please be careful
    map.erase(keys.begin(), keys.end());

    return 0;
}

And the compile result is:

demo/build/_deps/cuco-src/include/cuco/detail/static_map.inl(645): error: static assertion failed
      static_assert(sizeof(Value) == sizeof(atomic_mapped_type));
      ^

Then I used int64_t as the value_type, and everything worked correctly. So how can I resolve this issue when using cuda::std::array<float, 4> as the value_type?

[PointKernel]

This is the case you want to use hash table as a mapping table and store indices instead of actual keys/values. Please the check sample code I shared previously https://godbolt.org/z/v5qGjTbxv