mirror of
https://github.com/smyalygames/FiniteVolumeGPU.git
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212 lines
8.4 KiB
Plaintext
212 lines
8.4 KiB
Plaintext
/*
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This OpenCL kernel implements the second order HLL flux
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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 <hip/hip_runtime.h>
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#include "include/common.h"
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#include "include/SWECommon.h"
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#include "include/limiters.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 Qx[3][BLOCK_HEIGHT + 4][BLOCK_WIDTH + 4],
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float F[3][BLOCK_HEIGHT + 4][BLOCK_WIDTH + 4],
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const float g_, const float dx_, const float dt_) {
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for (unsigned int j = threadIdx.y; j < BLOCK_HEIGHT + 4; j += BLOCK_HEIGHT) {
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for (unsigned int i = threadIdx.x + 1; i < BLOCK_WIDTH + 2; i += BLOCK_WIDTH) {
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// Reconstruct point values of Q at the left and right hand side
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// of the cell for both the left (i) and right (i+1) cell
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const float3 Q_rl = make_float3(Q[0][j][i + 1] - 0.5f * Qx[0][j][i + 1],
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Q[1][j][i + 1] - 0.5f * Qx[1][j][i + 1],
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Q[2][j][i + 1] - 0.5f * Qx[2][j][i + 1]);
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const float3 Q_rr = make_float3(Q[0][j][i + 1] + 0.5f * Qx[0][j][i + 1],
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Q[1][j][i + 1] + 0.5f * Qx[1][j][i + 1],
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Q[2][j][i + 1] + 0.5f * Qx[2][j][i + 1]);
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const float3 Q_ll = make_float3(Q[0][j][i] - 0.5f * Qx[0][j][i],
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Q[1][j][i] - 0.5f * Qx[1][j][i],
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Q[2][j][i] - 0.5f * Qx[2][j][i]);
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const float3 Q_lr = make_float3(Q[0][j][i] + 0.5f * Qx[0][j][i],
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Q[1][j][i] + 0.5f * Qx[1][j][i],
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Q[2][j][i] + 0.5f * Qx[2][j][i]);
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//Evolve half a timestep (predictor step)
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const float3 Q_r_bar = Q_rl + dt_ / (2.0f * dx_) * (F_func(Q_rl, g_) - F_func(Q_rr, g_));
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const float3 Q_l_bar = Q_lr + dt_ / (2.0f * dx_) * (F_func(Q_ll, g_) - F_func(Q_lr, g_));
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// Compute flux based on prediction
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const float3 flux = HLL_flux(Q_l_bar, Q_r_bar, g_);
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//Write to shared memory
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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 x-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 Qy[3][BLOCK_HEIGHT + 4][BLOCK_WIDTH + 4],
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float G[3][BLOCK_HEIGHT + 4][BLOCK_WIDTH + 4],
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const float g_, const float dy_, const float dt_) {
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for (unsigned int j = threadIdx.y + 1; j < BLOCK_HEIGHT + 2; j += BLOCK_HEIGHT) {
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for (unsigned int i = threadIdx.x; i < BLOCK_WIDTH + 4; i += BLOCK_WIDTH) {
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// Reconstruct point values of Q at the left and right hand side
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// of the cell for both the left (i) and right (i+1) cell
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// Note that hu and hv are swapped ("transposing" the domain)!
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const float3 Q_rl = make_float3(Q[0][j + 1][i] - 0.5f * Qy[0][j + 1][i],
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Q[2][j + 1][i] - 0.5f * Qy[2][j + 1][i],
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Q[1][j + 1][i] - 0.5f * Qy[1][j + 1][i]);
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const float3 Q_rr = make_float3(Q[0][j + 1][i] + 0.5f * Qy[0][j + 1][i],
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Q[2][j + 1][i] + 0.5f * Qy[2][j + 1][i],
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Q[1][j + 1][i] + 0.5f * Qy[1][j + 1][i]);
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const float3 Q_ll = make_float3(Q[0][j][i] - 0.5f * Qy[0][j][i],
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Q[2][j][i] - 0.5f * Qy[2][j][i],
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Q[1][j][i] - 0.5f * Qy[1][j][i]);
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const float3 Q_lr = make_float3(Q[0][j][i] + 0.5f * Qy[0][j][i],
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Q[2][j][i] + 0.5f * Qy[2][j][i],
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Q[1][j][i] + 0.5f * Qy[1][j][i]);
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// Evolve half a timestep (predictor step)
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const float3 Q_r_bar = Q_rl + dt_ / (2.0f * dy_) * (F_func(Q_rl, g_) - F_func(Q_rr, g_));
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const float3 Q_l_bar = Q_lr + dt_ / (2.0f * dy_) * (F_func(Q_ll, g_) - F_func(Q_lr, g_));
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// Compute flux based on prediction
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const float3 flux = HLL_flux(Q_l_bar, Q_r_bar, g_);
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// Write to shared memory
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// Note that we here swap hu and hv back to the original
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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 HLL2Kernel(
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const int nx_, const int ny_,
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const float dx_, const float dy_, const float dt_,
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const float g_,
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const float theta_,
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const int step_,
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const int boundary_conditions_,
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// Input h^n
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float *h0_ptr_, const int h0_pitch_,
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float *hu0_ptr_, const int hu0_pitch_,
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float *hv0_ptr_, const int hv0_pitch_,
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// Output h^{n+1}
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float *h1_ptr_, const int h1_pitch_,
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float *hu1_ptr_, const int hu1_pitch_,
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float *hv1_ptr_, const int hv1_pitch_,
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// Output CFL
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float *cfl_,
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// Subarea of internal domain to compute
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const int x0 = 0, const int y0 = 0,
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int x1 = 0, int y1 = 0) {
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if (x1 == 0)
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x1 = nx_;
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if (y1 == 0)
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y1 = ny_;
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constexpr unsigned int w = BLOCK_WIDTH;
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constexpr unsigned int h = BLOCK_HEIGHT;
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constexpr unsigned int gc_x = 2;
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constexpr unsigned int gc_y = 2;
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constexpr 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 Qx[3][h + 4][w + 4];
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__shared__ float F[3][h + 4][w + 4];
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// Read into shared memory
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readBlock<w, h, gc_x, gc_y, 1, 1>(h0_ptr_, h0_pitch_, Q[0], nx_, ny_, boundary_conditions_, x0, y0, x1, y1);
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readBlock<w, h, gc_x, gc_y, -1, 1>(hu0_ptr_, hu0_pitch_, Q[1], nx_, ny_, boundary_conditions_, x0, y0, x1, y1);
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readBlock<w, h, gc_x, gc_y, 1, -1>(hv0_ptr_, hv0_pitch_, Q[2], nx_, ny_, boundary_conditions_, x0, y0, x1, y1);
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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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minmodSlopeX<w, h, gc_x, gc_y, vars>(Q, Qx, theta_);
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__syncthreads();
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computeFluxF(Q, Qx, F, g_, dx_, dt_);
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__syncthreads();
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evolveF<w, h, gc_x, gc_y, vars>(Q, F, dx_, dt_);
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__syncthreads();
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// Compute fluxes along the y-axis and evolve
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minmodSlopeY<w, h, gc_x, gc_y, vars>(Q, Qx, theta_);
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__syncthreads();
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computeFluxG(Q, Qx, F, g_, dy_, dt_);
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__syncthreads();
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evolveG<w, h, gc_x, gc_y, 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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minmodSlopeY<w, h, gc_x, gc_y, vars>(Q, Qx, theta_);
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__syncthreads();
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computeFluxG(Q, Qx, F, g_, dy_, dt_);
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__syncthreads();
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evolveG<w, h, gc_x, gc_y, vars>(Q, F, dy_, dt_);
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__syncthreads();
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// Compute fluxes along the x-axis and evolve
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minmodSlopeX<w, h, gc_x, gc_y, vars>(Q, Qx, theta_);
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__syncthreads();
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computeFluxF(Q, Qx, F, g_, dx_, dt_);
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__syncthreads();
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evolveF<w, h, gc_x, gc_y, 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, gc_x, gc_y>(h1_ptr_, h1_pitch_, Q[0], nx_, ny_, 0, 1, x0, y0, x1, y1);
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writeBlock<w, h, gc_x, gc_y>(hu1_ptr_, hu1_pitch_, Q[1], nx_, ny_, 0, 1, x0, y0, x1, y1);
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writeBlock<w, h, gc_x, gc_y>(hv1_ptr_, hv1_pitch_, Q[2], nx_, ny_, 0, 1, x0, y0, x1, y1);
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// Compute the CFL for this block
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if (cfl_ != nullptr) {
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writeCfl<w, h, gc_x, gc_y, vars>(Q, F[0], nx_, ny_, dx_, dy_, g_, cfl_);
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}
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}
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} // extern "C"
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