is evaluated during constant evaluation, then A is executed, otherwise B14 if consteval  Why?  We have std::is_constant_evaluated(), so what’s wrong with: if (std::is_constant_evaluated()) { /*A*/ which you cannot do in /*A*/ above  if consteval cannot be used wrong is_constant_evaluated() can: if constexpr (std::is_constant_evaluated()) { /*A*/ } else { /*B*/ }15 if consteval  Example: consteval std::println("{}", std::ranges::contains_subrange(v1, v2)); // true75 Changes to Ranges Library  Several folding algorithms: ranges::fold_left(), fold_left_first(), fold_right(), fold_right_last(), fold_left_with_iter()

information  Includes the library feature test macros, such as:  __cpp_lib_any, __cpp_lib_bool_constant, __cpp_lib_filesystem, …71 Immediate Functions – consteval  constexpr function  might be Immediate Functions – consteval  consteval function  required to always produce a constant at compile time, a non- constant result should be a compilation error  called: immediate functions consteval InchToMm(const_inch) }; // Fine, everything is constant ✔ double dynamic_inch { 8 }; const auto mm2 { InchToMm(dynamic_inch) }; // Compilation error: not constant ❌73 constinit  Static initialization order

(GH-399, Neargye) • More: • P0415R1 constexpr Again (GH-367, Neargye) • P0595R2 is_constant_evaluated() (GH-353, Jennifer Yao – MSVC compiler) • P1006R1 constexpr pointer_to() (GH-397, AdamBucior) key, using the container's predicate • Ordered: "Logarithmic" time, O(K + log N) • Unordered: "Constant" time, average O(K), worst O(N) • Only std::erase_if() is provided for associative • Avoids potential

JVM 内存模型 Heap Method Area Runtime Constant Pool Thread Thread Thread PC Register JVM Stack Native Method Stack PC Register JVM Stack Native Method Stack PC Register JVM Stack Native Method

std::duration from , contains:  A tick  A tick period = seconds between 2 ticks = rational constant  template > class duration {...}  Rep = type to represent

那样用循环。 下一课主题？ GPU vs CPU • cudaStream 异步编程（流水线式并行） • Nsight profiler 性能分析（和 Vtune 类似） • texture 与 constant 内存（为啥要他们？） • 动态内存分配（ GPU 上调用 malloc/free ） • curand 、 cufft 、 cublas 等常用库（大概） • GPU 红黑高斯 + 多重网格实战