hw06 done

main.cpp

@@ -6,34 +6,80 @@
 #include <algorithm>
 #include "ticktock.h"
 
+#include <tbb/parallel_for.h>
+#include <tbb/parallel_reduce.h>
+#include <tbb/parallel_scan.h>
+#include <mutex>
+#include "pod.h"
+
 // TODO: 并行化所有这些 for 循环
 
+// origin:
+// fill: 0.713545s
+// fill: 0.726485s
+// saxpy: 0.0369504s
+// sqrtdot: 0.0733301s
+// 5165.4
+// minvalue: 0.0715443s
+// -1.11803
+// magicfilter: 0.190107s
+// 55924034
+// scanner: 0.0710648s
+// 6.18926e+07
+
+// parallel:
+// fill: 0.106531s
+// fill: 0.109878s
+// saxpy: 0.0345495s
+// sqrtdot: 0.0193823s
+// 5792.61
+// minvalue: 0.0108345s
+// -1.11803
+// magicfilter: 0.126976s
+// 55924034
+// scanner: 0.0371496s
+// 6.19079e+07
+
 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++) {
-        arr[i] = func(i);
-    }
+    tbb::parallel_for(
+        tbb::blocked_range<size_t>(0, arr.size()),
+        [&](tbb::blocked_range<size_t> r) {
+            for (size_t i = r.begin(); i < r.end(); ++i)
+                arr[i] = func(i);
+        });
     TOCK(fill);
     return arr;
 }
 
 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(
+        tbb::blocked_range<size_t>(0, x.size()),
+        [&](tbb::blocked_range<size_t> r) {
+            for (size_t i = r.begin(); i < r.end(); ++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];
-    }
+    ret = tbb::parallel_reduce(
+        tbb::blocked_range<size_t>(0, std::min(x.size(), y.size())),
+        static_cast<T>(0),
+        [&](tbb::blocked_range<size_t> r, T temp_sum) {
+            for (size_t i = r.begin(); i < r.end(); ++i)
+                temp_sum += x[i] * y[i];
+            return temp_sum;
+        },
+        [](T a, T b) {
+            return a + b;
+        });
     ret = std::sqrt(ret);
     TOCK(sqrtdot);
     return ret;
@@ -43,26 +89,47 @@ 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];
-    }
+    ret = tbb::parallel_reduce(
+        tbb::blocked_range<size_t>(1, x.size()),
+        x[0],
+        [&](tbb::blocked_range<size_t> r, T temp_min) {
+            for ( size_t i = r.begin(); i < r.end(); ++i)
+                if (temp_min > x[i])
+                    temp_min = x[i];
+            return temp_min;
+        },
+        [](T a, T b) {
+            return std::min(a, b);
+        }
+    );
     TOCK(minvalue);
-    return ret;
+    return ret; 
 }
 
 template <class T>
-std::vector<T> magicfilter(std::vector<T> const &x, std::vector<T> const &y) {
+std::vector<pod<T>> 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<pod<T>> res;
+    res.reserve(2 * std::min(x.size(), y.size()));
+    std::mutex mtx;
+    tbb::parallel_for(
+        tbb::blocked_range<size_t>(0, std::min(x.size(), y.size())),
+        [&](tbb::blocked_range<size_t> r) {
+            std::vector<pod<T>> cache;
+            cache.reserve(2 * r.size());
+            for (size_t i = r.begin(); i < r.end(); ++i) {
+                if (x[i] > y[i])
+                    cache.push_back(x[i]);
+                else if (y[i] > x[i] && y[i] > 0.5f) {
+                    cache.push_back(y[i]);
+                    cache.push_back(x[i] * y[i]);
+                }
+            }
+            std::lock_guard lck(mtx);
+            std::copy(cache.begin(), cache.end(), std::back_inserter(res));
         }
-    }
+    );
+
     TOCK(magicfilter);
     return res;
 }
@@ -71,10 +138,21 @@ 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;
-    }
+    ret = tbb::parallel_scan(
+        tbb::blocked_range<size_t>(0, x.size()),
+        static_cast<T>(0),
+        [&] (tbb::blocked_range<size_t> r, T temp_sum, auto is_final) {
+            for (size_t i = r.begin(); i < r.end(); i++) {
+                temp_sum += x[i];
+                if (is_final) 
+                    x[i] = temp_sum;
+            }
+            return temp_sum;
+        },
+        [] (T a, T b) {
+            return  a + b;
+        }
+    );
     TOCK(scanner);
     return ret;
 }