topk_softmax (#1592)

* topk_softmax

* remove some file

* fix atomix linear_offset

* address various comment, and change sfc get_index api to static(tuple)

include/ck_tile/host/fill.hpp

@@ -10,6 +10,7 @@
 #include <random>
 #include <type_traits>
 #include <utility>
+#include <unordered_set>
 
 #include "ck_tile/core.hpp"
 
@@ -41,6 +42,73 @@ struct FillUniformDistribution
     }
 };
 
+namespace impl {
+
+// clang-format off
+template<index_t bytes> struct RawIntegerType_ {};
+template<> struct RawIntegerType_<1> { using type = uint8_t;};
+template<> struct RawIntegerType_<2> { using type = uint16_t;};
+template<> struct RawIntegerType_<4> { using type = uint32_t;};
+template<> struct RawIntegerType_<8> { using type = uint64_t;};
+// clang-format on
+
+template <typename T>
+using RawIntegerType = typename RawIntegerType_<sizeof(T)>::type;
+} // namespace impl
+
+// Note: this struct will have no const-ness will generate random
+template <typename T>
+struct FillUniformDistribution_Unique
+{
+    float a_{-5.f};
+    float b_{5.f};
+    std::optional<uint32_t> seed_{11939};
+
+    std::mt19937 gen_{};
+    std::unordered_set<impl::RawIntegerType<T>> set_{};
+
+    FillUniformDistribution_Unique(float a                      = -5.f,
+                                   float b                      = 5.f,
+                                   std::optional<uint32_t> seed = {11939})
+        : a_(a),
+          b_(b),
+          seed_(seed),
+          gen_{seed_.has_value() ? *seed_ : std::random_device{}()},
+          set_{}
+    {
+    }
+
+    template <typename ForwardIter>
+    void operator()(ForwardIter first, ForwardIter last)
+    {
+        std::mt19937& gen = gen_;
+        std::uniform_real_distribution<float> dis(a_, b_);
+        auto& set = set_;
+        std::generate(first, last, [&dis, &gen, &set]() {
+            T v = static_cast<T>(0);
+            do
+            {
+                v = ck_tile::type_convert<T>(dis(gen));
+            } while(set.count(bit_cast<impl::RawIntegerType<T>>(v)) == 1);
+            set.insert(bit_cast<impl::RawIntegerType<T>>(v));
+
+            return v;
+        });
+    }
+
+    template <typename ForwardRange>
+    auto operator()(ForwardRange&& range)
+        -> std::void_t<decltype(std::declval<FillUniformDistribution_Unique&>()(
+            std::begin(std::forward<ForwardRange>(range)),
+            std::end(std::forward<ForwardRange>(range))))>
+    {
+        (*this)(std::begin(std::forward<ForwardRange>(range)),
+                std::end(std::forward<ForwardRange>(range)));
+    }
+
+    void clear() { set_.clear(); }
+};
+
 template <typename T>
 struct FillNormalDistribution
 {