Fixed order again

GPUSimulators/cuda/EulerCommon.h

@@ -23,6 +23,60 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 
 
+template<int w, int h, int gc_x, int gc_y, int vars>
+__device__ void writeCfl(float Q[vars][h+2*gc_y][w+2*gc_x],
+        float shmem[h+2*gc_y][w+2*gc_x],
+        const int nx_, const int ny_,
+        const float dx_, const float dy_, const float gamma_,
+        float* output_) {
+    //Index of thread within block
+    const int tx = threadIdx.x + gc_x;
+    const int ty = threadIdx.y + gc_y;
+    
+    //Index of cell within domain
+    const int ti = blockDim.x*blockIdx.x + tx;
+    const int tj = blockDim.y*blockIdx.y + ty;
+    
+    //Only internal cells
+    if (ti < nx_+gc_x && tj < ny_+gc_y) {
+        const float rho = Q[0][ty][tx];
+        const float u   = Q[1][ty][tx] / rho;
+        const float v   = Q[2][ty][tx] / rho;
+        
+        const float max_u = dx_ / (fabsf(u) + sqrtf(gamma_*rho));
+        const float max_v = dy_ / (fabsf(v) + sqrtf(gamma_*rho));
+        
+        shmem[ty][tx] = fminf(max_u, max_v);
+    }
+    __syncthreads();
+    
+    //One row of threads loop over all rows
+    if (ti < nx_+gc_x && tj < ny_+gc_y) {
+        if (ty == gc_y) {
+            float min_val = shmem[ty][tx];
+            const int max_y = min(h, ny_+gc_y - tj);
+            for (int j=gc_y; j<max_y+gc_y; j++) {
+                min_val = fminf(min_val, shmem[j][tx]);
+            }
+            shmem[ty][tx] = min_val;
+        }
+    }
+    __syncthreads();
+    
+    //One thread loops over first row to find global max
+    if (tx == gc_x && ty == gc_y) {
+        float min_val = shmem[ty][tx];
+        const int max_x = min(w, nx_+gc_x - ti);
+        for (int i=gc_x; i<max_x+gc_x; ++i) {
+            min_val = fminf(min_val, shmem[ty][i]);
+        }
+        
+        const int idx = gridDim.x*blockIdx.y + blockIdx.x;
+        output_[idx] = min_val;
+    }
+}
+
+