added update_select_rows for select_linear:update speed-up

1 files changed, 20 insertions, 0 deletions

diff --git a/nerv/lib/matrix/generic/cukernel.cu b/nerv/lib/matrix/generic/cukernel.cu
index 08feb59..6c8e64a 100644
--- a/nerv/lib/matrix/generic/cukernel.cu
+++ b/nerv/lib/matrix/generic/cukernel.cu
@@ -225,6 +225,15 @@ __global__ void cudak_(clip)(MATRIX_ELEM *a,
             a[j + i * stride] = val_1;
 }
 
+__global__ void cudak_(update_select_rows)(MATRIX_ELEM *c, const MATRIX_ELEM *a, const MATRIX_ELEM *idx,
+                            int nrow_a, int ncol_a, int stride_c, int stride_a, double alpha, double beta) {
+    int j = blockIdx.x * blockDim.x + threadIdx.x;
+    int i = blockIdx.y * blockDim.y + threadIdx.y;
+    if (i >= nrow_a || j >= ncol_a) return;
+    int i_c = lrintf(idx[i]);
+    c[j + i_c * stride_c] = c[j + i_c * stride_c] * (1 - beta * alpha) + a[j + i * stride_a] * alpha;
+}
+
 __global__ void cudak_(expand_frm)(const MATRIX_ELEM *a, MATRIX_ELEM *b,
                                     int nrow, int ncol,
                                     int enrow, int encol,
@@ -540,6 +549,17 @@ extern "C" {
             a->stride / sizeof(MATRIX_ELEM), val_1, val_2);
         cudaStreamSynchronize(0);
     }
+    
+    void cudak_(cuda_update_select_rows)(Matrix *c, const Matrix *a, const Matrix *idx, double alpha, double beta) {
+        dim3 threadsPerBlock(CUDA_THREADS_N, CUDA_THREADS_N);
+        dim3 numBlocks(CEIL_DIV(a->ncol, threadsPerBlock.x),
+                CEIL_DIV(a->nrow, threadsPerBlock.y));
+        cudak_(update_select_rows)<<<numBlocks, threadsPerBlock>>> \
+            (MATRIX_ELEM_PTR(c), MATRIX_ELEM_PTR(a), MATRIX_ELEM_PTR(idx), 
+             a->nrow, a->ncol, c->stride / sizeof(MATRIX_ELEM), 
+             a->stride / sizeof(MATRIX_ELEM), alpha, beta);
+        cudaStreamSynchronize(0);
+    }
 
     void cudak_(cuda_expand_frm)(const Matrix *a, Matrix *b, int context) {
         dim3 threadsPerBlock(CUDA_THREADS_N, CUDA_THREADS_N);