Merge branch 'master' into solution-319

README.md

@@ -12,6 +12,7 @@
 
 ### Tips
 
+* [[320]](https://github.com/QuantlabFinancial/cpp_tip_of_the_week/blob/master/tips/320.md) - Did you know about intrisincts to support SIMD (Single Instruction, Multiple Data) instructions?
 * [[319]](https://github.com/QuantlabFinancial/cpp_tip_of_the_week/blob/master/tips/319.md) - Did you know that C++11 allows calling functions with reference-to-array parameters from an initializer list?
 * [[318]](https://github.com/QuantlabFinancial/cpp_tip_of_the_week/blob/master/tips/318.md) - Did you know that `std::unique_ptr` can be constexpr in C++23?
 * [[317]](https://github.com/QuantlabFinancial/cpp_tip_of_the_week/blob/master/tips/317.md) - Did you know that with C++20 you can pass concepts?

tips/319.md

@@ -48,11 +48,44 @@ consteval auto sum_n(const auto (&... x)[2])
 
 > https://godbolt.org/z/1fxxz6KEv
 
-```cpp
+```
 template <typename... Ts, int... Ns>
 consteval auto sum_n(const Ts (&...x)[Ns]) {
     return (... + std::ranges::fold_left(x, Ts{}, std::plus{}));
 }
 ```
 
 > https://godbolt.org/z/bKdz3EEr1
+
+```
+template <auto... Ns>
+constexpr auto sum_n(auto (&&...values)[Ns]) {
+  auto sum = 0;
+  return ([&] {
+    for (auto value : values) {
+      sum += value;
+    }
+  }(), ..., sum);
+}
+```
+
+> https://godbolt.org/z/x7jn47Geb
+
+```cpp
+template<auto N>
+consteval auto sum_n(const auto  (&...array)[N]) {
+    auto result = (std::accumulate(array, array + N, 0) + ...);
+    return result;
+}
+```
+
+> https://godbolt.org/z/rGG7KM7qa
+
+```cpp
+template<class... Lists, int ...N>
+consteval auto sum_n(const Lists (&...v)[N]) {
+    return (std::accumulate(v, v+N, 0) + ...);
+}
+```
+
+> https://godbolt.org/z/9hYTe14ds

tips/320.md

@@ -0,0 +1,64 @@
+<details open><summary>Info</summary><p>
+
+* **Did you know about intrisincts to support SIMD (Single Instruction, Multiple Data) instructions?**
+
+  * https://www.intel.com/content/www/us/en/docs/intrinsics-guide/index.html
+
+</p></details><details open><summary>Example</summary><p>
+
+```cpp
+#include <immintrin.h>
+
+int main() {
+    const std::vector a = {1, 2, 3, 4};
+    const std::vector b = {5, 6, 7, 8};
+
+    const auto va = _mm_loadu_si128((__m128i*)a.data());
+    const auto vb = _mm_loadu_si128((__m128i*)b.data());
+    const auto result = _mm_add_epi32(va, vb);
+
+    std::vector<int> v(a.size());
+    _mm_storeu_si128((__m128i*)v.data(), result);
+
+    assert((std::vector{1 + 5, 2 + 6, 3 + 7, 4 + 8} == v));
+}
+```
+
+> https://godbolt.org/z/nz1hx76j7
+
+</p></details><details open><summary>Puzzle</summary><p>
+
+> **Can you implement a function which computes the dot product of the two arrays using SIMD instructions?**
+
+```cpp
+[[nodiscard]] constexpr auto dot_product(const auto& lhs, const auto& rhs); // TODO
+
+int main() {
+    using namespace boost::ut;
+
+    "simd.dot_product empty"_test = [] {
+        const std::vector<float> a{};
+        const std::vector<float> b{};
+
+        expect(0_i == dot_product(a, b));
+    };
+
+    "simd.dot_product one"_test = [] {
+        const std::vector a = {1.f};
+        const std::vector b = {3.f};
+
+        expect(_i(1*3) == dot_product(a, b));
+    };
+
+    "simd.dot_product many"_test = [] {
+        const std::vector a = {1.f, 2.f, 3.f, 4.f};
+        const std::vector b = {5.f, 6.f, 7.f, 8.f};
+
+        expect(_i(1*5+2*6+3*7+4*8) == dot_product(a, b));
+    };
+}
+```
+
+> https://godbolt.org/z/GnrEh1YM9
+
+</p></details><details><summary>Solutions</summary><p>