1 files changed, 21 insertions, 2 deletions

diff --git a/nerv/matrix/generic/cumatrix.c b/nerv/matrix/generic/cumatrix.c
index 08cb4c2..e1519b0 100644
--- a/nerv/matrix/generic/cumatrix.c
+++ b/nerv/matrix/generic/cumatrix.c
@@ -247,8 +247,8 @@ static int nerv_matrix_(lua_copy_rows_fromd_by_idx)(lua_State *L) {
     const Matrix *b = luaT_checkudata(L, 2, nerv_matrix_(tname));
     const Matrix *idx = luaT_checkudata(L, 3, nerv_matrix_(tname));
     long nrow = a->nrow;
-    int b_begin = lua_gettop(L) > 3 ? luaL_checkinteger(L, 4) : 0;
-    nerv_matrix_(copy_rows_fromd_by_idx)(a, b, idx, b_begin, &status);
+    int idx_begin = lua_gettop(L) > 3 ? luaL_checkinteger(L, 4) : 0;
+    nerv_matrix_(copy_rows_fromd_by_idx)(a, b, idx, idx_begin, &status);
     NERV_LUA_CHECK_STATUS(L, status);
     return 0;
 }
@@ -291,6 +291,22 @@ static int nerv_matrix_(lua_scale_rows_by_row)(lua_State *L) {
     return 0;
 }
 
+#ifdef __NERV_FUTURE_CUDA_7
+static int nerv_matrix_(lua_update_select_rows)(lua_State *L) {
+    /* update c's select rows,
+     * i.e. c[idx[i]] = c[idx[i]] * (1 - beta * alpha) + a[i] * alpha */
+    Status status;
+    Matrix *c = luaT_checkudata(L, 1, nerv_matrix_(tname));
+    const Matrix *a = luaT_checkudata(L, 2, nerv_matrix_(tname));
+    const Matrix *idx = luaT_checkudata(L, 3, nerv_matrix_(tname));
+    MATRIX_ELEM alpha = luaL_checknumber(L, 4);
+    MATRIX_ELEM beta = luaL_checknumber(L, 5);
+    nerv_matrix_(update_select_rows)(c, a, idx, alpha, beta, &status);
+    NERV_LUA_CHECK_STATUS(L, status);
+    return 0;
+}
+#endif
+
 static const luaL_Reg nerv_matrix_(extra_methods)[] = {
     {"colsum", nerv_matrix_(lua_colsum)},
     {"colsame", nerv_matrix_(lua_colsame)},
@@ -321,6 +337,9 @@ static const luaL_Reg nerv_matrix_(extra_methods)[] = {
     {"rearrange_frm", nerv_matrix_(lua_rearrange_frm)},
     {"scale_rows_by_row", nerv_matrix_(lua_scale_rows_by_row)},
     {"scale_rows_by_col", nerv_matrix_(lua_scale_rows_by_col)},
+#ifdef __NERV_FUTURE_CUDA_7
+    {"update_select_rows", nerv_matrix_(lua_update_select_rows)},
+#endif
     {NULL, NULL}
 };