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#include <thread>
#include <mutex>
#include <tuple>
#include <cassert>
#include "compute_host.h"
#include "host_aberth.h"
#include "polygen.h"
#include "util.h"
using namespace std;
vector<int> computeHost(int W, int H, Com bottomLeft, Com topRight) {
constexpr const int numThreads = 4;
static_assert(ispow2(numThreads));
cerr << "Finding roots for " << PolyGen::numPolys() << " polynomials" << endl;
vector<int> counts(W * H);
mutex countsMutex;
vector<PolyGen::Job> jobs = PolyGen::genJobs(numThreads);
assert(jobs.size() == numThreads);
vector<thread> threads(jobs.size());
for (int i = 0; i < (int)jobs.size(); i++) {
threads[i] = thread([W, H, &counts, &countsMutex, job = jobs[i], bottomLeft, topRight]() {
auto calcIndex = [](double value, double left, double right, int steps) -> int {
return (value - left) / (right - left) * (steps - 1) + 0.5;
};
auto calcPos = [W, H, bottomLeft, topRight, &calcIndex](Com z) -> pair<int, int> {
return make_pair(
calcIndex(z.real(), bottomLeft.real(), topRight.real(), W),
calcIndex(z.imag(), topRight.imag(), bottomLeft.imag(), H)
);
};
vector<int> localCounts(W * H);
Poly poly = job.init;
for (int i = 0; i < job.numItems; i++) {
for (Com z : aberth(poly)) {
int x, y;
tie(x, y) = calcPos(z);
if (0 <= x && x < W && 0 <= y && y < H) {
localCounts[W * y + x]++;
}
}
PolyGen::next(poly);
}
lock_guard<mutex> guard(countsMutex);
for (int i = 0; i < W * H; i++) counts[i] += localCounts[i];
});
}
for (thread &th : threads) th.join();
return counts;
}
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