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little optimization to gpts and mine space partition bucket sort

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This commit is contained in:
Richard Thier 2022-12-10 11:04:53 +01:00
parent 7e21807668
commit 50b1997d5c
3 changed files with 485 additions and 442 deletions
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38
gptsort.h
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@ -2,6 +2,7 @@
#include <vector>
#include <algorithm>
// ChatGPT and me did this space partitioning bucket sort
void gpt_bucket_sort(uint32_t* array, int n) {
// Calculate the number of buckets to use
int num_buckets = std::sqrt(n);
@ -36,3 +37,40 @@ void gpt_bucket_sort(uint32_t* array, int n) {
}
}
}
// Further optimizations (no chatGPT)
void my_bucket_sort(uint32_t* array, int n) {
// Calculate the number of buckets to use
int num_buckets = std::sqrt(n);
// Create a vector of buckets
std::vector<std::vector<uint32_t>> buckets(num_buckets);
// Calculate the range of values that each bucket can hold
auto mm = std::minmax_element(array, array + n);
uint32_t min_value = *mm.first;
uint32_t max_value = *mm.second;
uint32_t range = max_value - min_value + 1;
uint32_t bucket_size = range / num_buckets + 1;
// Distribute the elements of the array into the buckets
for (int i = 0; i < n; i++) {
// Calculate the bucket index for this element
// using the range of values and the bucket size as the divisor
int bucket_index = (array[i] - min_value) / bucket_size;
buckets[bucket_index].push_back(array[i]);
}
// Sort the elements in each bucket using std::sort
for (int i = 0; i < num_buckets; i++) {
std::sort(buckets[i].begin(), buckets[i].end());
}
// Concatenate the buckets to get the sorted array
int k = 0;
for (int i = 0; i < num_buckets; i++) {
for (int j = 0; j < buckets[i].size(); j++) {
array[k++] = buckets[i][j];
}
}
}

3
makefile
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@ -31,5 +31,8 @@ clang_release: test.cpp magyarsort.h
clang_release3: test.cpp magyarsort.h
clang++ test.cpp -DNDEBUG -std=c++17 -O3 -o test.out
clang_release_ypsu: ypsu.cpp magyarsort.h
clang++ ypsu.cpp -DNDEBUG -std=c++17 -O2 -o ypsu.out
clean: test.out
rm test.out

12
ypsu.cpp
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@ -399,7 +399,8 @@
fflush(stdout);
std::vector<uint32_t> v(n);
v = geninput(inputtype, n);
measure(inputtype, "sp", [&] { spsort(&v[0], v.size()); });
//measure(inputtype, "sp", [&] { spsort(&v[0], v.size()); });
measure(inputtype, "magyar", [&] { MagyarSort::sort<uint32_t>(&v[0], v.size()); });
for (auto r : results) printf("%9.3fs", r.second);
puts("");
@ -414,8 +415,8 @@
}
int main(void) {
int n = 100000000;
//int n = 10000000;
//int n = 100000000;
int n = 10000000;
//int n = 100;
// Uncomment this for profiling and alg!
@ -457,16 +458,17 @@
w = v;
measure(inputtype, "4pasu", [&] { fourpassu(&w[0], w.size()); });
assert(w == expected);
*/
w = v;
measure(inputtype, "4rot", [&] { fourrots(&w[0], w.size()); });
assert(w == expected);
w = v;
/*measure(inputtype, "sp", [&] { spsort(&w[0], w.size()); });
measure(inputtype, "sp", [&] { spsort(&w[0], w.size()); });
assert(w == expected);
w = v;*/
measure(inputtype, "gptbuck", [&] { gpt_bucket_sort(&w[0], w.size()); });
assert(w == expected);
measure(inputtype, "mybuck", [&] { my_bucket_sort(&w[0], w.size()); });
assert(w == expected);
/*
w = v;
measure(inputtype, "frewr", [&] { frewr(&w[0], w.size()); });