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//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
// * Neither the name of NVIDIA CORPORATION nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ``AS IS'' AND ANY
// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
// PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
// OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// Copyright (c) 2018 NVIDIA Corporation. All rights reserved.
#ifndef RAND_STATE_H
#define RAND_STATE_H
// This is shared by legacy IOFX and shaders
namespace nvidia
{
namespace apex
{
struct LCG_PRNG
{
unsigned int a, c;
PX_CUDA_CALLABLE PX_INLINE LCG_PRNG()
{
}
PX_CUDA_CALLABLE PX_INLINE LCG_PRNG(unsigned int a, unsigned int c)
{
this->a = a;
this->c = c;
}
static PX_CUDA_CALLABLE PX_INLINE LCG_PRNG getIdentity()
{
return LCG_PRNG(1, 0);
}
static PX_CUDA_CALLABLE PX_INLINE LCG_PRNG getDefault()
{
return LCG_PRNG(1103515245u, 12345u);
}
PX_CUDA_CALLABLE PX_INLINE LCG_PRNG& operator *= (const LCG_PRNG& rhs)
{
a *= rhs.a;
c *= rhs.a; c += rhs.c;
return *this;
}
PX_CUDA_CALLABLE PX_INLINE LCG_PRNG leapFrog(unsigned int leap) const
{
LCG_PRNG ret = getIdentity();
for (unsigned int i = 0; i < leap; ++i)
{
ret *= (*this);
}
return ret;
}
PX_CUDA_CALLABLE PX_INLINE unsigned int operator()(unsigned int x) const
{
return x * a + c;
}
};
struct RandState
{
explicit PX_CUDA_CALLABLE PX_INLINE RandState(unsigned int seed)
{
curr = seed;
}
PX_CUDA_CALLABLE PX_INLINE unsigned int next()
{
return (curr = LCG_PRNG::getDefault()(curr));
}
PX_CUDA_CALLABLE PX_INLINE float nextFloat()
{
return float(next()) * 0.00000000023283064365386962890625f;
}
PX_CUDA_CALLABLE PX_INLINE float nextFloat(float min, float max)
{
return min + nextFloat() * (max - min);
}
private:
unsigned int curr;
};
// For CUDA PRNG
struct PRNGInfo
{
unsigned int* g_stateSpawnSeed;
nvidia::LCG_PRNG* g_randBlock;
unsigned int seed;
nvidia::LCG_PRNG randThread;
nvidia::LCG_PRNG randGrid;
};
// For CUDA PRNG: device part
#ifdef __CUDACC__
//*
#if __CUDA_ARCH__ >= 300
#define RAND_SCAN_OP(ofs) \
{ \
unsigned int a = aData[scanIdx], c = cData[scanIdx]; \
unsigned int aOfs = __shfl_up(a, ofs), cOfs = __shfl_up(c, ofs); \
if (idxInWarp >= ofs) { a = a * aOfs; c = c * aOfs + cOfs; } \
aData[scanIdx] = a; cData[scanIdx] = c; \
}
#else
#define RAND_SCAN_OP(ofs) \
{ \
unsigned int a = aData[scanIdx], c = cData[scanIdx]; \
unsigned int aOfs = aData[scanIdx - ofs], cOfs = cData[scanIdx - ofs]; \
aData[scanIdx] = a * aOfs; cData[scanIdx] = c * aOfs + cOfs; \
}
#endif
/*/
//THIS CODE CRASH ON CUDA 5.0.35
#define RAND_SCAN_OP(ofs) \
{ \
nvidia::LCG_PRNG val(aData[scanIdx], cData[scanIdx]); \
nvidia::LCG_PRNG valOfs(aData[scanIdx - ofs], cData[scanIdx - ofs]); \
val *= valOfs; \
aData[scanIdx] = val.a; cData[scanIdx] = val.c; \
}
//*/
PX_INLINE __device__ void randScanWarp(unsigned int scanIdx, volatile unsigned int* aData, volatile unsigned int* cData, unsigned int idxInWarp)
{
RAND_SCAN_OP(1);
RAND_SCAN_OP(2);
RAND_SCAN_OP(4);
RAND_SCAN_OP(8);
RAND_SCAN_OP(16);
}
PX_INLINE __device__ nvidia::LCG_PRNG randScanBlock(nvidia::LCG_PRNG val, volatile unsigned int* aData, volatile unsigned int* cData)
{
const unsigned int idx = threadIdx.x;
const unsigned int idxInWarp = idx & (WARP_SIZE-1);
const unsigned int warpIdx = (idx >> LOG2_WARP_SIZE);
//setup scan
unsigned int scanIdx = (warpIdx << (LOG2_WARP_SIZE + 1)) + idxInWarp;
//write identity
aData[scanIdx] = 1;
cData[scanIdx] = 0;
scanIdx += WARP_SIZE;
//write value
aData[scanIdx] = val.a;
cData[scanIdx] = val.c;
randScanWarp(scanIdx, aData, cData, idxInWarp);
//read value
val.a = aData[scanIdx];
val.c = cData[scanIdx];
__syncthreads();
if (idxInWarp == WARP_SIZE-1)
{
const unsigned int idxWrite = warpIdx + WARP_SIZE;
aData[idxWrite] = val.a;
cData[idxWrite] = val.c;
}
__syncthreads();
if (warpIdx == 0)
{
randScanWarp(scanIdx, aData, cData, idxInWarp);
}
__syncthreads();
if (warpIdx > 0)
{
const unsigned int idxRead = warpIdx + WARP_SIZE - 1;
const nvidia::LCG_PRNG valWarp(aData[idxRead], cData[idxRead]);
val *= valWarp;
}
return val;
}
#endif
}
} // nvidia::apex::
#endif
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