mirror of
https://github.com/smyalygames/FiniteVolumeGPU.git
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130 lines
3.9 KiB
C++
130 lines
3.9 KiB
C++
/*
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This file implements different flux and slope limiters
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Copyright (C) 2016, 2017, 2018 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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#pragma once
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/**
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* Reconstructs a slope using the generalized minmod limiter based on three
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* consecutive values
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*/
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__device__ __inline__ float minmodSlope(float left, float center, float right, float theta) {
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const float backward = (center - left) * theta;
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const float central = (right - left) * 0.5f;
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const float forward = (right - center) * theta;
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return 0.25f
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*copysign(1.0f, backward)
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*(copysign(1.0f, backward) + copysign(1.0f, central))
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*(copysign(1.0f, central) + copysign(1.0f, forward))
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*min( min(fabs(backward), fabs(central)), fabs(forward) );
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}
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/**
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* Reconstructs a minmod slope for a whole block along the abscissa
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*/
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template<int block_width, int block_height, int ghost_cells, int vars>
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__device__ void minmodSlopeX(float Q[vars][block_height+2*ghost_cells][block_width+2*ghost_cells],
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float Qx[vars][block_height+2*(ghost_cells-1)][block_width+2*(ghost_cells-1)],
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const float theta_) {
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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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const int j = ty;
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const int l = j + ghost_cells; //Skip ghost cells
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//Reconstruct slopes along x axis
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for (int i=tx; i<block_width+2*(ghost_cells-1); i+=block_width) {
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const int k = i + 1;
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for (int p=0; p<vars; ++p) {
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Qx[p][j][i] = minmodSlope(Q[p][l][k-1], Q[p][l][k], Q[p][l][k+1], theta_);
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}
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}
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}
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/**
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* Reconstructs a minmod slope for a whole block along the ordinate
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*/
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template<int block_width, int block_height, int ghost_cells, int vars>
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__device__ void minmodSlopeY(float Q[vars][block_height+2*ghost_cells][block_width+2*ghost_cells],
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float Qy[vars][block_height+2*(ghost_cells-1)][block_width+2*(ghost_cells-1)],
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const float theta_) {
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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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const int i = tx;
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const int k = i + ghost_cells; //Skip ghost cells
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//Reconstruct slopes along y axis
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for (int j=ty; j<block_height+2*(ghost_cells-1); j+=block_height) {
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const int l = j + 1;
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for (int p=0; p<vars; ++p) {
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Qy[p][j][i] = minmodSlope(Q[p][l-1][k], Q[p][l][k], Q[p][l+1][k], theta_);
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}
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}
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}
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__device__ float monotonized_central(float r_) {
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return fmaxf(0.0f, fminf(2.0f, fminf(2.0f*r_, 0.5f*(1.0f+r_))));
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}
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__device__ float osher(float r_, float beta_) {
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return fmaxf(0.0f, fminf(beta_, r_));
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}
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__device__ float sweby(float r_, float beta_) {
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return fmaxf(0.0f, fmaxf(fminf(r_, beta_), fminf(beta_*r_, 1.0f)));
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}
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__device__ float minmod(float r_) {
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return fmaxf(0.0f, fminf(1.0f, r_));
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}
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__device__ float generalized_minmod(float r_, float theta_) {
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return fmaxf(0.0f, fminf(theta_*r_, fminf( (1.0f + r_) / 2.0f, theta_)));
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}
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__device__ float superbee(float r_) {
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return fmaxf(0.0f, fmaxf(fminf(2.0f*r_, 1.0f), fminf(r_, 2.0f)));
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}
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__device__ float vanAlbada1(float r_) {
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return (r_*r_ + r_) / (r_*r_ + 1.0f);
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}
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__device__ float vanAlbada2(float r_) {
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return 2.0f*r_ / (r_*r_* + 1.0f);
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}
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__device__ float vanLeer(float r_) {
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return (r_ + fabsf(r_)) / (1.0f + fabsf(r_));
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} |