sobol.h

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// SPDX-License-Identifier: Apache-2.0
// Copyright Contributors to the OpenQMC Project.
 
 
#pragma once
 
#include "gpu.h"
#include "owen.h"
#include "sampler.h"
#include "state.h"
 
#include <cstddef>
#include <cstdint>
 
namespace oqmc
{
 
class SobolImpl
{
    // See SamplerInterface for public API documentation.
    friend SamplerInterface<SobolImpl>;
 
    static constexpr std::size_t cacheSize = 0;
    static void initialiseCache(void* cache);
 
    /*AUTO_DEFINED*/ SobolImpl() = default;
    OQMC_HOST_DEVICE SobolImpl(State64Bit state);
    OQMC_HOST_DEVICE SobolImpl(int x, int y, int frame, int index,
                               const void* cache);
 
    OQMC_HOST_DEVICE SobolImpl newDomain(int key) const;
    OQMC_HOST_DEVICE SobolImpl newDomainSplit(int key, int size,
                                              int index) const;
    OQMC_HOST_DEVICE SobolImpl newDomainDistrib(int key, int index) const;
 
    template <int Size>
    OQMC_HOST_DEVICE void drawSample(std::uint32_t sample[Size]) const;
 
    template <int Size>
    OQMC_HOST_DEVICE void drawRnd(std::uint32_t rnd[Size]) const;
 
    State64Bit state;
};
 
inline void SobolImpl::initialiseCache([[maybe_unused]] void* cache)
{
}
 
inline SobolImpl::SobolImpl(State64Bit state) : state(state)
{
}
 
inline SobolImpl::SobolImpl(int x, int y, int frame, int index,
                            [[maybe_unused]] const void* cache)
    : state(x, y, frame, index)
{
    state = state.pixelDecorrelate();
}
 
inline SobolImpl SobolImpl::newDomain(int key) const
{
    return {state.newDomain(key)};
}
 
inline SobolImpl SobolImpl::newDomainSplit(int key, int size, int index) const
{
    return {state.newDomainSplit(key, size, index)};
}
 
inline SobolImpl SobolImpl::newDomainDistrib(int key, int index) const
{
    return {state.newDomainDistrib(key, index)};
}
 
template <int Size>
void SobolImpl::drawSample(std::uint32_t sample[Size]) const
{
    shuffledScrambledSobol<Size>(state.sampleId, pcg::output(state.patternId),
                                 sample);
}
 
template <int Size>
void SobolImpl::drawRnd(std::uint32_t rnd[Size]) const
{
    state.drawRnd<Size>(rnd);
}
 
using SobolSampler = SamplerInterface<SobolImpl>;
 
} // namespace oqmc