xgboost/src/common/optional_weight.h

33 lines
1.2 KiB
C++

/**
* Copyright 2022-2023 by XGBoost Contributors
*/
#ifndef XGBOOST_COMMON_OPTIONAL_WEIGHT_H_
#define XGBOOST_COMMON_OPTIONAL_WEIGHT_H_
#include "xgboost/base.h" // XGBOOST_DEVICE
#include "xgboost/context.h" // Context
#include "xgboost/host_device_vector.h" // HostDeviceVector
#include "xgboost/span.h" // Span
namespace xgboost::common {
struct OptionalWeights {
Span<float const> weights;
float dft{1.0f}; // fixme: make this compile time constant
explicit OptionalWeights(Span<float const> w) : weights{w} {}
explicit OptionalWeights(float w) : dft{w} {}
XGBOOST_DEVICE float operator[](size_t i) const { return weights.empty() ? dft : weights[i]; }
[[nodiscard]] auto Empty() const { return weights.empty(); }
[[nodiscard]] auto Size() const { return weights.size(); }
};
inline OptionalWeights MakeOptionalWeights(Context const* ctx,
HostDeviceVector<float> const& weights) {
if (ctx->IsCUDA()) {
weights.SetDevice(ctx->Device());
}
return OptionalWeights{ctx->IsCUDA() ? weights.ConstDeviceSpan() : weights.ConstHostSpan()};
}
} // namespace xgboost::common
#endif // XGBOOST_COMMON_OPTIONAL_WEIGHT_H_