mirror of
https://github.com/smyalygames/FiniteVolumeGPU.git
synced 2025-05-18 14:34:13 +02:00
209 lines
6.3 KiB
Plaintext
209 lines
6.3 KiB
Plaintext
/*
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This OpenCL kernel implements the Kurganov-Petrova numerical scheme
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for the shallow water equations, described in
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A. Kurganov & Guergana Petrova
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A Second-Order Well-Balanced Positivity Preserving Central-Upwind
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Scheme for the Saint-Venant System Communications in Mathematical
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Sciences, 5 (2007), 133-160.
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Copyright (C) 2016 SINTEF ICT
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "common.h"
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#include "SWECommon.h"
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/**
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* Computes the flux along the x axis for all faces
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*/
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__device__
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void computeFluxF(float Q[3][BLOCK_HEIGHT+4][BLOCK_WIDTH+4],
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float F[3][BLOCK_HEIGHT+1][BLOCK_WIDTH+1],
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const float g_, const float dx_, const float dt_) {
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//Index of thread within block
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const int tx = threadIdx.x;
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const int ty = threadIdx.y;
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{
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int j=ty;
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const int l = j + 2; //Skip ghost cells
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for (int i=tx; i<BLOCK_WIDTH+1; i+=BLOCK_WIDTH) {
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const int k = i + 1;
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// Q at interface from the right and left
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const float3 Ql2 = make_float3(Q[0][l][k-1], Q[1][l][k-1], Q[2][l][k-1]);
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const float3 Ql1 = make_float3(Q[0][l][k ], Q[1][l][k ], Q[2][l][k ]);
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const float3 Qr1 = make_float3(Q[0][l][k+1], Q[1][l][k+1], Q[2][l][k+1]);
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const float3 Qr2 = make_float3(Q[0][l][k+2], Q[1][l][k+2], Q[2][l][k+2]);
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// Computed flux
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const float3 flux = WAF_1D_flux(Ql2, Ql1, Qr1, Qr2, g_, dx_, dt_);
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F[0][j][i] = flux.x;
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F[1][j][i] = flux.y;
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F[2][j][i] = flux.z;
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}
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}
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}
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/**
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* Computes the flux along the y axis for all faces
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*/
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__device__
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void computeFluxG(float Q[3][BLOCK_HEIGHT+4][BLOCK_WIDTH+4],
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float G[3][BLOCK_HEIGHT+1][BLOCK_WIDTH+1],
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const float g_, const float dy_, const float dt_) {
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//Index of thread within block
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const int tx = threadIdx.x;
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const int ty = threadIdx.y;
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//Compute fluxes along the y axis
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for (int j=ty; j<BLOCK_HEIGHT+1; j+=BLOCK_HEIGHT) {
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const int l = j + 1;
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{
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int i=tx;
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const int k = i + 2; //Skip ghost cells
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// Q at interface from the right and left
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// Note that we swap hu and hv
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const float3 Ql2 = make_float3(Q[0][l-1][k], Q[2][l-1][k], Q[1][l-1][k]);
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const float3 Ql1 = make_float3(Q[0][l ][k], Q[2][l ][k], Q[1][l ][k]);
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const float3 Qr1 = make_float3(Q[0][l+1][k], Q[2][l+1][k], Q[1][l+1][k]);
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const float3 Qr2 = make_float3(Q[0][l+2][k], Q[2][l+2][k], Q[1][l+2][k]);
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// Computed flux
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// Note that we swap back
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const float3 flux = WAF_1D_flux(Ql2, Ql1, Qr1, Qr2, g_, dy_, dt_);
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G[0][j][i] = flux.x;
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G[1][j][i] = flux.z;
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G[2][j][i] = flux.y;
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}
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}
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}
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extern "C" {
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__global__ void WAFKernel(
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int nx_, int ny_,
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float dx_, float dy_, float dt_,
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float g_, int step_,
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//Input h^n
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float* h0_ptr_, int h0_pitch_,
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float* hu0_ptr_, int hu0_pitch_,
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float* hv0_ptr_, int hv0_pitch_,
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//Output h^{n+1}
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float* h1_ptr_, int h1_pitch_,
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float* hu1_ptr_, int hu1_pitch_,
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float* hv1_ptr_, int hv1_pitch_) {
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const unsigned int w = BLOCK_WIDTH;
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const unsigned int h = BLOCK_HEIGHT;
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const unsigned int gc = 2;
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const unsigned int vars = 3;
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//Shared memory variables
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__shared__ float Q[3][h+4][w+4];
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__shared__ float F[3][h+1][w+1];
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//Read into shared memory Q from global memory
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readBlock<w, h, gc>( h0_ptr_, h0_pitch_, Q[0], nx_+2, ny_+2);
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readBlock<w, h, gc>(hu0_ptr_, hu0_pitch_, Q[1], nx_+2, ny_+2);
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readBlock<w, h, gc>(hv0_ptr_, hv0_pitch_, Q[2], nx_+2, ny_+2);
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__syncthreads();
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//Set boundary conditions
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noFlowBoundary<w, h, gc, 1, 1>(Q[0], nx_, ny_);
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noFlowBoundary<w, h, gc, -1, 1>(Q[1], nx_, ny_);
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noFlowBoundary<w, h, gc, 1, -1>(Q[2], nx_, ny_);
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__syncthreads();
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//Step 0 => evolve x first, then y
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if (step_ == 0) {
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//Compute fluxes along the x axis and evolve
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computeFluxF(Q, F, g_, dx_, dt_);
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__syncthreads();
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evolveF<w, h, gc, vars>(Q, F, dx_, dt_);
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__syncthreads();
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//Fix boundary conditions
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noFlowBoundary<w, h, gc, 1, 1>(Q[0], nx_, ny_);
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noFlowBoundary<w, h, gc, -1, 1>(Q[1], nx_, ny_);
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noFlowBoundary<w, h, gc, 1, -1>(Q[2], nx_, ny_);
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__syncthreads();
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//Compute fluxes along the y axis and evolve
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computeFluxG(Q, F, g_, dy_, dt_);
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__syncthreads();
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evolveG<w, h, gc, vars>(Q, F, dy_, dt_);
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__syncthreads();
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}
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//Step 1 => evolve y first, then x
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else {
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//Compute fluxes along the y axis and evolve
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computeFluxG(Q, F, g_, dy_, dt_);
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__syncthreads();
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evolveG<w, h, gc, vars>(Q, F, dy_, dt_);
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__syncthreads();
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//Fix boundary conditions
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noFlowBoundary<w, h, gc, 1, 1>(Q[0], nx_, ny_);
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noFlowBoundary<w, h, gc, -1, 1>(Q[1], nx_, ny_);
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noFlowBoundary<w, h, gc, 1, -1>(Q[2], nx_, ny_);
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__syncthreads();
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//Compute fluxes along the x axis and evolve
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computeFluxF(Q, F, g_, dx_, dt_);
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__syncthreads();
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evolveF<w, h, gc, vars>(Q, F, dx_, dt_);
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__syncthreads();
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}
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// Write to main memory for all internal cells
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writeBlock<w, h, 2>( h1_ptr_, h1_pitch_, Q[0], nx_, ny_);
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writeBlock<w, h, 2>(hu1_ptr_, hu1_pitch_, Q[1], nx_, ny_);
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writeBlock<w, h, 2>(hv1_ptr_, hv1_pitch_, Q[2], nx_, ny_);
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}
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} // extern "C" |