mirror of
https://github.com/NVIDIA/cuda-samples.git
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227 lines
9.7 KiB
Plaintext
227 lines
9.7 KiB
Plaintext
/* Copyright (c) 2021, NVIDIA CORPORATION. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* * Neither the name of NVIDIA CORPORATION nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ``AS IS'' AND ANY
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* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
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* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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////////////////////////////////////////////////////////////////////////////////
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// Global types
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////////////////////////////////////////////////////////////////////////////////
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#include <stdlib.h>
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#include <stdio.h>
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#include <cooperative_groups.h>
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namespace cg = cooperative_groups;
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#include <helper_cuda.h>
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#include <curand_kernel.h>
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#include "MonteCarlo_common.h"
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////////////////////////////////////////////////////////////////////////////////
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// Helper reduction template
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// Please see the "reduction" CUDA Sample for more information
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////////////////////////////////////////////////////////////////////////////////
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#include "MonteCarlo_reduction.cuh"
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////////////////////////////////////////////////////////////////////////////////
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// Internal GPU-side data structures
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////////////////////////////////////////////////////////////////////////////////
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#define MAX_OPTIONS (1024 * 1024)
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// Preprocessed input option data
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typedef struct {
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real S;
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real X;
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real MuByT;
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real VBySqrtT;
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} __TOptionData;
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////////////////////////////////////////////////////////////////////////////////
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// Overloaded shortcut payoff functions for different precision modes
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////////////////////////////////////////////////////////////////////////////////
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__device__ inline float endCallValue(float S, float X, float r, float MuByT,
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float VBySqrtT) {
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float callValue = S * __expf(MuByT + VBySqrtT * r) - X;
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return (callValue > 0.0F) ? callValue : 0.0F;
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}
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__device__ inline double endCallValue(double S, double X, double r,
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double MuByT, double VBySqrtT) {
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double callValue = S * exp(MuByT + VBySqrtT * r) - X;
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return (callValue > 0.0) ? callValue : 0.0;
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}
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#define THREAD_N 256
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////////////////////////////////////////////////////////////////////////////////
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// This kernel computes the integral over all paths using a single thread block
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// per option. It is fastest when the number of thread blocks times the work per
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// block is high enough to keep the GPU busy.
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////////////////////////////////////////////////////////////////////////////////
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static __global__ void MonteCarloOneBlockPerOption(
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curandState *__restrict rngStates,
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const __TOptionData *__restrict d_OptionData,
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__TOptionValue *__restrict d_CallValue, int pathN, int optionN) {
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// Handle to thread block group
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cg::thread_block cta = cg::this_thread_block();
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cg::thread_block_tile<32> tile32 = cg::tiled_partition<32>(cta);
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const int SUM_N = THREAD_N;
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__shared__ real s_SumCall[SUM_N];
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__shared__ real s_Sum2Call[SUM_N];
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// determine global thread id
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int tid = threadIdx.x + blockIdx.x * blockDim.x;
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// Copy random number state to local memory for efficiency
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curandState localState = rngStates[tid];
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for (int optionIndex = blockIdx.x; optionIndex < optionN;
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optionIndex += gridDim.x) {
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const real S = d_OptionData[optionIndex].S;
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const real X = d_OptionData[optionIndex].X;
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const real MuByT = d_OptionData[optionIndex].MuByT;
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const real VBySqrtT = d_OptionData[optionIndex].VBySqrtT;
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// Cycle through the entire samples array:
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// derive end stock price for each path
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// accumulate partial integrals into intermediate shared memory buffer
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for (int iSum = threadIdx.x; iSum < SUM_N; iSum += blockDim.x) {
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__TOptionValue sumCall = {0, 0};
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#pragma unroll 8
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for (int i = iSum; i < pathN; i += SUM_N) {
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real r = curand_normal(&localState);
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real callValue = endCallValue(S, X, r, MuByT, VBySqrtT);
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sumCall.Expected += callValue;
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sumCall.Confidence += callValue * callValue;
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}
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s_SumCall[iSum] = sumCall.Expected;
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s_Sum2Call[iSum] = sumCall.Confidence;
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}
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// Reduce shared memory accumulators
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// and write final result to global memory
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cg::sync(cta);
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sumReduce<real, SUM_N, THREAD_N>(s_SumCall, s_Sum2Call, cta, tile32,
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&d_CallValue[optionIndex]);
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}
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}
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static __global__ void rngSetupStates(curandState *rngState, int device_id) {
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// determine global thread id
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int tid = threadIdx.x + blockIdx.x * blockDim.x;
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// Each threadblock gets different seed,
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// Threads within a threadblock get different sequence numbers
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curand_init(blockIdx.x + gridDim.x * device_id, threadIdx.x, 0,
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&rngState[tid]);
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}
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////////////////////////////////////////////////////////////////////////////////
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// Host-side interface to GPU Monte Carlo
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////////////////////////////////////////////////////////////////////////////////
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extern "C" void initMonteCarloGPU(TOptionPlan *plan) {
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checkCudaErrors(cudaMalloc(&plan->d_OptionData,
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sizeof(__TOptionData) * (plan->optionCount)));
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checkCudaErrors(cudaMalloc(&plan->d_CallValue,
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sizeof(__TOptionValue) * (plan->optionCount)));
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checkCudaErrors(cudaMallocHost(&plan->h_OptionData,
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sizeof(__TOptionData) * (plan->optionCount)));
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// Allocate internal device memory
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checkCudaErrors(cudaMallocHost(&plan->h_CallValue,
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sizeof(__TOptionValue) * (plan->optionCount)));
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// Allocate states for pseudo random number generators
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checkCudaErrors(cudaMalloc((void **)&plan->rngStates,
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plan->gridSize * THREAD_N * sizeof(curandState)));
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checkCudaErrors(cudaMemset(plan->rngStates, 0,
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plan->gridSize * THREAD_N * sizeof(curandState)));
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// place each device pathN random numbers apart on the random number sequence
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rngSetupStates<<<plan->gridSize, THREAD_N>>>(plan->rngStates, plan->device);
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getLastCudaError("rngSetupStates kernel failed.\n");
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}
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// Compute statistics and deallocate internal device memory
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extern "C" void closeMonteCarloGPU(TOptionPlan *plan) {
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for (int i = 0; i < plan->optionCount; i++) {
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const double RT = plan->optionData[i].R * plan->optionData[i].T;
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const double sum = plan->h_CallValue[i].Expected;
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const double sum2 = plan->h_CallValue[i].Confidence;
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const double pathN = plan->pathN;
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// Derive average from the total sum and discount by riskfree rate
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plan->callValue[i].Expected = (float)(exp(-RT) * sum / pathN);
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// Standard deviation
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double stdDev = sqrt((pathN * sum2 - sum * sum) / (pathN * (pathN - 1)));
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// Confidence width; in 95% of all cases theoretical value lies within these
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// borders
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plan->callValue[i].Confidence =
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(float)(exp(-RT) * 1.96 * stdDev / sqrt(pathN));
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}
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checkCudaErrors(cudaFree(plan->rngStates));
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checkCudaErrors(cudaFreeHost(plan->h_CallValue));
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checkCudaErrors(cudaFreeHost(plan->h_OptionData));
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checkCudaErrors(cudaFree(plan->d_CallValue));
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checkCudaErrors(cudaFree(plan->d_OptionData));
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}
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// Main computations
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extern "C" void MonteCarloGPU(TOptionPlan *plan, cudaStream_t stream) {
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__TOptionValue *h_CallValue = plan->h_CallValue;
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if (plan->optionCount <= 0 || plan->optionCount > MAX_OPTIONS) {
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printf("MonteCarloGPU(): bad option count.\n");
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return;
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}
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__TOptionData *h_OptionData = (__TOptionData *)plan->h_OptionData;
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for (int i = 0; i < plan->optionCount; i++) {
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const double T = plan->optionData[i].T;
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const double R = plan->optionData[i].R;
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const double V = plan->optionData[i].V;
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const double MuByT = (R - 0.5 * V * V) * T;
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const double VBySqrtT = V * sqrt(T);
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h_OptionData[i].S = (real)plan->optionData[i].S;
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h_OptionData[i].X = (real)plan->optionData[i].X;
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h_OptionData[i].MuByT = (real)MuByT;
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h_OptionData[i].VBySqrtT = (real)VBySqrtT;
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}
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checkCudaErrors(cudaMemcpyAsync(plan->d_OptionData, h_OptionData,
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plan->optionCount * sizeof(__TOptionData),
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cudaMemcpyHostToDevice, stream));
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MonteCarloOneBlockPerOption<<<plan->gridSize, THREAD_N, 0, stream>>>(
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plan->rngStates, (__TOptionData *)(plan->d_OptionData),
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(__TOptionValue *)(plan->d_CallValue), plan->pathN, plan->optionCount);
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getLastCudaError("MonteCarloOneBlockPerOption() execution failed\n");
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checkCudaErrors(cudaMemcpyAsync(h_CallValue, plan->d_CallValue,
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plan->optionCount * sizeof(__TOptionValue),
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cudaMemcpyDeviceToHost, stream));
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// cudaDeviceSynchronize();
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}
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