From 348dbafa70d2484880ebaf1d2a6ae1cc773bbeaa Mon Sep 17 00:00:00 2001
From: jty233 <65076292+jty233@users.noreply.github.com>
Date: Fri, 24 Jun 2022 21:05:55 +0800
Subject: [PATCH] Update main.cpp

---
 main.cpp | 79 +++++++++++++++++++++++++++++++++-----------------------
 1 file changed, 46 insertions(+), 33 deletions(-)

diff --git a/main.cpp b/main.cpp
index a1d2625..ebe34d4 100644
--- a/main.cpp
+++ b/main.cpp
@@ -3,17 +3,18 @@
 #include <vector>
 #include <cmath>
 #include <numeric>
-#include <algorithm>
 #include "ticktock.h"
+#include <tbb/tbb.h>
+#include <atomic>
 
 // TODO: 并行化所有这些 for 循环
 
 template <class T, class Func>
 std::vector<T> fill(std::vector<T> &arr, Func const &func) {
     TICK(fill);
-    for (size_t i = 0; i < arr.size(); i++) {
+    tbb::parallel_for(0,(int)arr.size(),[&](auto i){
         arr[i] = func(i);
-    }
+    });
     TOCK(fill);
     return arr;
 }
@@ -21,19 +22,20 @@ std::vector<T> fill(std::vector<T> &arr, Func const &func) {
 template <class T>
 void saxpy(T a, std::vector<T> &x, std::vector<T> const &y) {
     TICK(saxpy);
-    for (size_t i = 0; i < x.size(); i++) {
-       x[i] = a * x[i] + y[i];
-    }
+    tbb::parallel_for(0,(int)x.size(),[&](auto i){
+        x[i] = a * x[i] + y[i];
+    });
     TOCK(saxpy);
 }
 
 template <class T>
 T sqrtdot(std::vector<T> const &x, std::vector<T> const &y) {
     TICK(sqrtdot);
-    T ret = 0;
-    for (size_t i = 0; i < std::min(x.size(), y.size()); i++) {
-        ret += x[i] * y[i];
-    }
+    T ret = tbb::parallel_reduce(tbb::blocked_range(0,(int)std::min(x.size(), y.size())),T{},[&](auto r,auto f){
+        for (int i = r.begin();i < r.end();i++)
+            f += x[i] * y[i];
+        return f;
+    },[](auto a,auto b){return a+b;});
     ret = std::sqrt(ret);
     TOCK(sqrtdot);
     return ret;
@@ -42,27 +44,34 @@ T sqrtdot(std::vector<T> const &x, std::vector<T> const &y) {
 template <class T>
 T minvalue(std::vector<T> const &x) {
     TICK(minvalue);
-    T ret = x[0];
-    for (size_t i = 1; i < x.size(); i++) {
-        if (x[i] < ret)
-            ret = x[i];
-    }
+    T ret = tbb::parallel_reduce(tbb::blocked_range(1,(int)x.size()),x[0],[&](auto r,auto f){
+        for (int i = r.begin();i < r.end();i++)
+            f = std::min(f,x[i]);
+        return f;
+    },[](auto a,auto b){return std::min(a,b);});
     TOCK(minvalue);
     return ret;
 }
 
 template <class T>
-std::vector<T> magicfilter(std::vector<T> const &x, std::vector<T> const &y) {
+auto magicfilter(std::vector<T> const &x, std::vector<T> const &y) {
     TICK(magicfilter);
-    std::vector<T> res;
-    for (size_t i = 0; i < std::min(x.size(), y.size()); i++) {
-        if (x[i] > y[i]) {
-            res.push_back(x[i]);
-        } else if (y[i] > x[i] && y[i] > 0.5f) {
-            res.push_back(y[i]);
-            res.push_back(x[i] * y[i]);
+    // std::vector<T> res(3 * std::min(x.size(), y.size()));
+    tbb::concurrent_vector<T> res;
+    // std::atomic<int> s = 0;
+    tbb::parallel_for(tbb::blocked_range(0,(int)std::min(x.size(), y.size())),[&](auto r){
+        std::vector<T> tmp;
+        for (size_t i = r.begin(); i < r.end(); i++) {
+            if (x[i] > y[i]) {
+                tmp.push_back(x[i]);
+            } else if (y[i] > x[i] && y[i] > 0.5f) {
+                tmp.push_back(y[i]);
+                tmp.push_back(x[i] * y[i]);
+            }
         }
-    }
+        auto it = res.grow_by(tmp.size());
+        std::copy(tmp.begin(),tmp.end(),it);
+    });
     TOCK(magicfilter);
     return res;
 }
@@ -70,24 +79,28 @@ std::vector<T> magicfilter(std::vector<T> const &x, std::vector<T> const &y) {
 template <class T>
 T scanner(std::vector<T> &x) {
     TICK(scanner);
-    T ret = 0;
-    for (size_t i = 0; i < x.size(); i++) {
-        ret += x[i];
-        x[i] = ret;
-    }
+    T ret = tbb::parallel_scan(tbb::blocked_range(0,(int)x.size()),T{},[&](auto r,auto f,auto final){
+        for (int i = r.begin();i < r.end();i++){
+            f += x[i];
+            if (final)
+                x[i] = f;
+        }
+        return f;
+    },[](auto a,auto b){return a + b;});
     TOCK(scanner);
     return ret;
 }
 
 int main() {
     size_t n = 1<<26;
-    std::vector<float> x(n);
-    std::vector<float> y(n);
+    std::vector<double> x(n);
+    std::vector<double> y(n);
+    
 
     fill(x, [&] (size_t i) { return std::sin(i); });
     fill(y, [&] (size_t i) { return std::cos(i); });
 
-    saxpy(0.5f, x, y);
+    saxpy(0.5, x, y);
 
     std::cout << sqrtdot(x, y) << std::endl;
     std::cout << minvalue(x) << std::endl;
@@ -97,6 +110,6 @@ int main() {
 
     scanner(x);
     std::cout << std::reduce(x.begin(), x.end()) << std::endl;
-
+    
     return 0;
 }