Fix bug in select function causing invalid vector size

Author: stijnh

include/kernel_float/iterate.h

@@ -225,7 +225,7 @@ struct concat_impl<V, Vs...> {
 template<>
 struct concat_impl<> {
     using value_type = void;
-    static constexpr size_t size = 1;
+    static constexpr size_t size = 0;
 
     template<typename U>
     KERNEL_FLOAT_INLINE static void call(U* output) {}

include/kernel_float/vector.h

@@ -23,6 +23,7 @@ namespace kernel_float {
  */
 template<typename T, typename E, class S>
 struct vector: public S {
+    using self_type = vector<T, E, S>;
     using value_type = T;
     using extent_type = E;
     using storage_type = S;
@@ -221,8 +222,8 @@ struct vector: public S {
      * vec<float, 4> vec2 = select(input, indices); // [0, 40, 40, 20]
      * ```
      */
-    template<typename V, typename... Is>
-    KERNEL_FLOAT_INLINE select_type<V, Is...> select(const Is&... indices) {
+    template<typename... Is>
+    KERNEL_FLOAT_INLINE select_type<self_type, Is...> select(const Is&... indices) {
         return kernel_float::select(*this, indices...);
     }
 

tests/iterate.cu

@@ -0,0 +1,47 @@
+#include "common.h"
+
+struct select_tests {
+    template<typename T>
+    __host__ __device__ void operator()(generator<T> gen) {
+        T data[8] = {
+            gen.next(),
+            gen.next(),
+            gen.next(),
+            gen.next(),
+            gen.next(),
+            gen.next(),
+            gen.next(),
+            gen.next()};
+        kf::vec<T, 8> x = {data[0], data[1], data[2], data[3], data[4], data[5], data[6], data[7]};
+
+        // Empty
+        ASSERT_EQ(select(x), (kf::vec<int, 0>()));
+        ASSERT_EQ(select(x, kf::vec<int, 0>()), (kf::vec<T, 0>()));
+
+        // One element
+        ASSERT_EQ(select(x, 0), kf::make_vec(data[0]));
+        ASSERT_EQ(select(x, 5), kf::make_vec(data[5]));
+        ASSERT_EQ(select(x, 7), kf::make_vec(data[4]));
+
+        // Two elements
+        ASSERT_EQ(select(x, 0, 1), kf::make_vec(data[0], data[1]));
+        ASSERT_EQ(select(x, 5, 0), kf::make_vec(data[5], data[0]));
+        ASSERT_EQ(select(x, 6, 7), kf::make_vec(data[6], data[7]));
+
+        // Two elements as array
+        ASSERT_EQ(select(x, kf::make_vec(0, 1)), kf::make_vec(data[0], data[1]));
+        ASSERT_EQ(select(x, kf::make_vec(5, 0)), kf::make_vec(data[5], data[0]));
+        ASSERT_EQ(select(x, kf::make_vec(6, 7)), kf::make_vec(data[6], data[7]));
+
+        // Three elements
+        ASSERT_EQ(select(x, kf::make_vec(0, 1), 2), kf::make_vec(data[0], data[1], data[2]));
+        ASSERT_EQ(select(x, kf::make_vec(5, 0, 7)), kf::make_vec(data[5], data[0], data[7]));
+        ASSERT_EQ(select(x, 6, kf::make_vec(7, 2)), kf::make_vec(data[6], data[7], data[2]));
+
+        // Method of vector
+        ASSERT_EQ(x.select(), (kf::vec<T, 0>()));
+        ASSERT_EQ(x.select(4), kf::make_vec(data[4]));
+        ASSERT_EQ(x.select(4, 2), kf::make_vec(data[4], data[2]));
+        ASSERT_EQ(x.select(4, 2, 7), kf::make_vec(data[4], data[2], data[7]));
+    }
+};